Added preparation for tree based service execution

Change-Id: I0112de33aa1458ffdd33ea9b755bffb30019671f
Signed-off-by: Dirk Fauth <Dirk.Fauth@de.bosch.com>

11 files changed, 929 insertions, 212 deletions

diff --git a/manager/src/main/java/org/eclipse/app4mc/cloud/manager/CloudServiceExecutionRunnable.java b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/CloudServiceExecutionRunnable.java
index 1bd7830..333c0a0 100644
--- a/manager/src/main/java/org/eclipse/app4mc/cloud/manager/CloudServiceExecutionRunnable.java
+++ b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/CloudServiceExecutionRunnable.java
@@ -66,10 +66,10 @@ public class CloudServiceExecutionRunnable implements Runnable {
 	public void run() {
 		try {
 			Path inputFile = this.storageService.load(this.uuid, this.originalFilename);
-			for (CloudServiceDefinition service : this.workflowStatus.getSelectedServices()) {
-				if (StringUtils.isEmpty(service)) {
-					continue;
-				}
+			
+			// TODO implement tree based processing with nested threads
+			
+			for (ServiceNode node : this.workflowStatus.getSelectedServices()) {
 				
 				// if an error occurred stop the workflow
 				if (!this.workflowStatus.getErrors().isEmpty()) {
@@ -77,7 +77,7 @@ public class CloudServiceExecutionRunnable implements Runnable {
 				}
 				
 				try {
-					inputFile = executeCloudService(service, this.workflowStatus, inputFile);
+					inputFile = executeCloudService(node, this.workflowStatus, inputFile);
 				} catch (ProcessingFailedException e) {
 					this.workflowStatus.addError(e.getMessage());
 				}
@@ -102,8 +102,10 @@ public class CloudServiceExecutionRunnable implements Runnable {
 		}
 	}
 		
-	private Path executeCloudService(CloudServiceDefinition csd, WorkflowStatus workflowStatus, Path inputFile) {
+	private Path executeCloudService(ServiceNode node, WorkflowStatus workflowStatus, Path inputFile) {
 		try {
+			CloudServiceDefinition csd = node.getService();
+			ServiceConfiguration config = node.getServiceConfiguration(); 
 			String serviceKey = csd.getKey();
 			String serviceName = csd.getName();
 			String baseUrl = csd.getBaseUrl();
@@ -112,7 +114,6 @@ public class CloudServiceExecutionRunnable implements Runnable {
 			MultipartBody multipartBody = Unirest.post(baseUrl)
 					.field("file", Files.newInputStream(inputFile), inputFile.getFileName().toString());
 			
-			ServiceConfiguration config = workflowStatus.getConfiguration(serviceKey); 
 			if (config != null) {
 				config.getParameterList().forEach(param -> {
 					if (!StringUtils.isEmpty(param.getValue()) && !param.isManagerParameter()) {
@@ -168,9 +169,8 @@ public class CloudServiceExecutionRunnable implements Runnable {
 				long end = System.currentTimeMillis();
 				
 				long timeout = 60_000l;
-				ServiceConfiguration serviceConfiguration = workflowStatus.getConfiguration(serviceKey);
-				if (serviceConfiguration != null) {
-					ServiceConfigurationParameter timeoutParam = serviceConfiguration.getParameter("timeout");
+				if (config != null) {
+					ServiceConfigurationParameter timeoutParam = config.getParameter("timeout");
 					if (timeoutParam != null) {
 						try {
 							timeout = Long.valueOf(timeoutParam.getValue());
@@ -294,8 +294,8 @@ public class CloudServiceExecutionRunnable implements Runnable {
 				}
 
 				boolean deleteResult = true;
-				if (serviceConfiguration != null) {
-					ServiceConfigurationParameter deleteParam = serviceConfiguration.getParameter("deleteResult");
+				if (config != null) {
+					ServiceConfigurationParameter deleteParam = config.getParameter("deleteResult");
 					if (deleteParam != null) {
 						deleteResult = Boolean.valueOf(deleteParam.getValue());
 					}
@@ -316,7 +316,7 @@ public class CloudServiceExecutionRunnable implements Runnable {
 			return result;
 
 		} catch (Exception e) {
-			throw new ProcessingFailedException("Error in " + csd.getName() + " workflow: " + e.getMessage(), e);
+			throw new ProcessingFailedException("Error in " + node.getService().getName() + " workflow: " + e.getMessage(), e);
 		}
 	}
 	
diff --git a/manager/src/main/java/org/eclipse/app4mc/cloud/manager/ServiceNode.java b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/ServiceNode.java
new file mode 100644
index 0000000..8951344
--- /dev/null
+++ b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/ServiceNode.java
@@ -0,0 +1,178 @@
+/*********************************************************************************
+ * Copyright (c) 2020 Robert Bosch GmbH and others.
+ *
+ * This program and the accompanying materials are made
+ * available under the terms of the Eclipse Public License 2.0
+ * which is available at https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Robert Bosch GmbH - initial API and implementation
+ ********************************************************************************
+ */
+package org.eclipse.app4mc.cloud.manager;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+
+import org.eclipse.app4mc.cloud.manager.administration.CloudServiceDefinition;
+
+public class ServiceNode {
+
+	private final String id;
+	private final CloudServiceDefinition service;
+	private final ServiceConfiguration config;
+	
+	private final List<ServiceNode> children = new ArrayList<>();
+
+	/**
+	 * Create a structural node like for example the root node.
+	 */
+	public ServiceNode(String id) {
+		if (id == null) {
+			throw new IllegalArgumentException("id can not be null!");
+		}
+		
+		this.id = id;
+		this.service = null;
+		this.config = null;
+	}
+	
+	/**
+	 * Create a service node for the given {@link CloudServiceDefinition} and
+	 * corresponding {@link ServiceConfiguration}.
+	 * 
+	 * @param service The {@link CloudServiceDefinition} to store in this node.
+	 * @param config  The {@link ServiceConfiguration} for the service.
+	 */
+	public ServiceNode(CloudServiceDefinition service, ServiceConfiguration config) {
+		if (service == null) {
+			throw new IllegalArgumentException("service parameter can not be null!");
+		}
+		this.id = service.getKey();
+		this.service = service;
+		this.config = config;
+	}
+
+	/**
+	 * 
+	 * @return The id of this node. A custom string for a structural node, the key
+	 *         of the {@link CloudServiceDefinition} for a service node.
+	 */
+	public String getId() {
+		return this.id;
+	}
+	
+	/**
+	 * 
+	 * @return The {@link CloudServiceDefinition} stored in this node.
+	 */
+	public CloudServiceDefinition getService() {
+		return service;
+	}
+
+	/**
+	 * 
+	 * @return The {@link ServiceConfiguration} for the
+	 *         {@link CloudServiceDefinition} stored in this node. Can be
+	 *         <code>null</code>.
+	 */
+	public ServiceConfiguration getServiceConfiguration() {
+		return config;
+	}
+
+	/**
+	 * Adds the given {@link ServiceNode} to the local children list.
+	 * 
+	 * @param node The {@link ServiceNode} to add.
+	 */
+	public void addChild(ServiceNode node) {
+		this.children.add(node);
+	}
+
+	/**
+	 * Adds a new child that references the given {@link CloudServiceDefinition}
+	 * with its corresponding {@link ServiceConfiguration}.
+	 * 
+	 * @param service The {@link CloudServiceDefinition} that should be added as a
+	 *                child node. Can not be <code>null</code>.
+	 * @param config  The corresponding {@link ServiceConfiguration} that provides
+	 *                configurations for the {@link CloudServiceDefinition}. Can be
+	 *                <code>null</code>.
+	 */
+	public void addChild(CloudServiceDefinition service, ServiceConfiguration config) {
+		this.children.add(new ServiceNode(service, config));
+	}
+	
+	/**
+	 * Removes the given {@link ServiceNode} from the local children list.
+	 * 
+	 * @param node The {@link ServiceNode} to remove.
+	 */
+	public void removeChild(ServiceNode node) {
+		this.children.remove(node);
+	}
+	
+	/**
+	 * Removes the given {@link ServiceNode} with the given id from the local
+	 * children list.
+	 * 
+	 * @param id The id of the {@link ServiceNode} to remove.
+	 */
+	public void removeChild(String id) {
+		for (Iterator<ServiceNode> it = this.children.iterator(); it.hasNext(); ) {
+			ServiceNode child = it.next();
+			if (child.getId().equals(id)) {
+				it.remove();
+			}
+		}
+	}
+	
+	/**
+	 * Removes the {@link ServiceNode} from the local children list that references
+	 * the given {@link CloudServiceDefinition}.
+	 * 
+	 * @param toRemove The {@link CloudServiceDefinition} for which the
+	 *                {@link ServiceNode} should be removed.
+	 */
+	public void removeChild(CloudServiceDefinition toRemove) {
+		for (Iterator<ServiceNode> it = this.children.iterator(); it.hasNext(); ) {
+			ServiceNode child = it.next();
+			if (child.getService().getKey().equals(toRemove.getKey())) {
+				it.remove();
+			}
+		}
+	}
+	
+	/**
+	 * 
+	 * @return An unmodifiable list of the child {@link ServiceNode}s in this node.
+	 */
+	public List<ServiceNode> getChildren() {
+		return Collections.unmodifiableList(this.children);
+	}
+
+	/**
+	 * Clear the locally mapped services in this node.
+	 */
+	public void clearChildren() {
+		this.children.clear();
+	}
+	
+	/**
+	 * 
+	 * @return <code>true</code> if this node is only used for structuring (e.g. a
+	 *         root node), <code>false</code> if it references a service definition.
+	 */
+	public boolean isStructuralNode() {
+		return this.service == null;
+	}
+	
+	@Override
+	public String toString() {
+		return this.id;
+	}
+}
diff --git a/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowConfigController.java b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowConfigController.java
index 81ced37..a85fb56 100644
--- a/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowConfigController.java
+++ b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowConfigController.java
@@ -113,7 +113,7 @@ public class WorkflowConfigController {
 				this.cloudServiceDefinitions);
 		
 		// add default service configurations if not specified
-		addDefaultConfigurations(workflowStatus);
+		WorkflowStatusHelper.addDefaultConfigurations(workflowStatus);
 		
 		if (workflowStatus == null) {
 			redirectAttributes.addFlashAttribute(
@@ -151,42 +151,6 @@ public class WorkflowConfigController {
 		return "redirect:/workflow?uuid=" + uuid;
 	}
 	
-	private void addDefaultConfigurations(WorkflowStatus workflowStatus) {
-		for (CloudServiceDefinition csd : workflowStatus.getSelectedServices()) {
-			// check if a configuration is already available
-			ServiceConfiguration configuration = workflowStatus.getConfiguration(csd.getKey());
-			if (configuration == null) {
-				configuration = new ServiceConfiguration(csd.getName());
-				workflowStatus.addConfiguration(csd.getKey(), configuration);
-			}
-			
-			ServiceConfigurationParameter timeOut = configuration.getParameter("timeout");
-			if (timeOut == null) {
-				timeOut = new ServiceConfigurationParameter();
-				timeOut.setName("Timeout (in ms)");
-				timeOut.setKey("timeout");
-				timeOut.setValue("60000");
-				if ("app4mc_sim".equals(csd.getKey())) {
-					timeOut.setValue("-1");
-				}
-				timeOut.setType("Long");
-				timeOut.setManagerParameter(true);
-				configuration.addParameter(timeOut);
-			}
-			
-			ServiceConfigurationParameter deleteResult = configuration.getParameter("deleteResult");
-			if (deleteResult == null) {
-				deleteResult = new ServiceConfigurationParameter();
-				deleteResult.setName("Delete result ");
-				deleteResult.setKey("deleteResult");
-				deleteResult.setValue("true");
-				deleteResult.setType("boolean");
-				deleteResult.setManagerParameter(true);
-				configuration.addParameter(deleteResult);
-			}
-		}
-	}
-	
 	@ModelAttribute("exampleModelFiles")
 	public List<String> exampleModelFiles() {
 		return this.exampleModelFiles;
diff --git a/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowController.java b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowController.java
index 23d4e6a..de19c13 100644
--- a/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowController.java
+++ b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowController.java
@@ -209,6 +209,8 @@ public class WorkflowController {
 		return "workflow";
 	}
 	
+	// TODO extend selection and removal of services to handle parents
+	
 	@PostMapping("/select/{selected}")
 	public String selectService(
 			@PathVariable(name = "selected") String selected,
@@ -223,8 +225,7 @@ public class WorkflowController {
 			return "workflow";
 		}
 
-		ws.addSelectedService(csd);
-		ws.addConfiguration(csd.getKey(), WorkflowStatusHelper.getConfigurationForService(csd));
+		ws.addSelectedService(csd, WorkflowStatusHelper.getConfigurationForService(csd));
 		
 		// render the form view
 		return "workflow";
@@ -242,7 +243,6 @@ public class WorkflowController {
 
 		if (csd != null) {
 			ws.removeSelectedService(csd);
-			ws.removeConfiguration(selected);
 		}
 		
 		// render the form view
@@ -331,11 +331,10 @@ public class WorkflowController {
 			return ResponseEntity.notFound().build();
 		}
 
-		// create archive of results
+		// create workflow configuration json
 		try {
 			WorkflowStatus config = new WorkflowStatus();
-			existing.getSelectedServices().forEach(config::addSelectedService);
-			existing.getConfigurations().entrySet().forEach(entry -> config.addConfiguration(entry.getKey(), entry.getValue()));
+			config.addAllSelectedServices(existing.getSelectedServices());
 			
 			return ResponseEntity
 					.ok()
diff --git a/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowRestController.java b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowRestController.java
index 6d95103..440ffa7 100644
--- a/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowRestController.java
+++ b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowRestController.java
@@ -97,7 +97,7 @@ public class WorkflowRestController {
 				this.cloudServiceDefinitions);
 		
 		// add default service configurations if not specified
-		addDefaultConfigurations(workflowStatus);
+		WorkflowStatusHelper.addDefaultConfigurations(workflowStatus);
 		
 		if (workflowStatus == null) {
 			return ResponseEntity
@@ -246,42 +246,6 @@ public class WorkflowRestController {
 		return ResponseEntity.ok().build();
 	}
 
-	private void addDefaultConfigurations(WorkflowStatus workflowStatus) {
-		for (CloudServiceDefinition csd : workflowStatus.getSelectedServices()) {
-			// check if a configuration is already available
-			ServiceConfiguration configuration = workflowStatus.getConfiguration(csd.getKey());
-			if (configuration == null) {
-				configuration = new ServiceConfiguration(csd.getName());
-				workflowStatus.addConfiguration(csd.getKey(), configuration);
-			}
-			
-			ServiceConfigurationParameter timeOut = configuration.getParameter("timeout");
-			if (timeOut == null) {
-				timeOut = new ServiceConfigurationParameter();
-				timeOut.setName("Timeout (in ms)");
-				timeOut.setKey("timeout");
-				timeOut.setValue("60000");
-				if ("app4mc_sim".equals(csd.getKey())) {
-					timeOut.setValue("-1");
-				}
-				timeOut.setType("Long");
-				timeOut.setManagerParameter(true);
-				configuration.addParameter(timeOut);
-			}
-			
-			ServiceConfigurationParameter deleteResult = configuration.getParameter("deleteResult");
-			if (deleteResult == null) {
-				deleteResult = new ServiceConfigurationParameter();
-				deleteResult.setName("Delete result ");
-				deleteResult.setKey("deleteResult");
-				deleteResult.setValue("true");
-				deleteResult.setType("boolean");
-				deleteResult.setManagerParameter(true);
-				configuration.addParameter(deleteResult);
-			}
-		}
-	}
-
 	@PreDestroy
 	public void dispose() {
 		this.executor.shutdownNow();
diff --git a/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowStatus.java b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowStatus.java
index 99d4f25..74bf577 100644
--- a/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowStatus.java
+++ b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowStatus.java
@@ -16,18 +16,23 @@ package org.eclipse.app4mc.cloud.manager;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
+import java.util.List;
 
 import org.eclipse.app4mc.cloud.manager.administration.CloudServiceDefinition;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 
 @JsonSerialize(using = WorkflowStatusSerializer.class)
 public class WorkflowStatus {
 
+	private static final Logger LOGGER = LoggerFactory.getLogger(WorkflowStatus.class);
+	
 	private String name;
 	private String uuid;
-	private ArrayList<CloudServiceDefinition> selectedServices = new ArrayList<>();
-	private HashMap<String, ServiceConfiguration> serviceConfigurations = new LinkedHashMap<>();
+	private ServiceNode rootNode = new ServiceNode("root");
+	
 	private ArrayList<String> messages = new ArrayList<>();
 	private ArrayList<String> errors = new ArrayList<>();
 	private HashMap<String, String> results = new LinkedHashMap<>();
@@ -43,6 +48,11 @@ public class WorkflowStatus {
 		this.name = name;
 	}
 
+	/**
+	 * 
+	 * @return The unique id of the workflow execution or <code>null</code> if the
+	 *         execution was not performed yet.
+	 */
 	public String getUuid() {
 		return uuid;
 	}
@@ -51,32 +61,178 @@ public class WorkflowStatus {
 		this.uuid = uuid;
 	}
 	
-	public ArrayList<CloudServiceDefinition> getSelectedServices() {
-		return selectedServices;
+	/**
+	 * 
+	 * @return The services on root level configured for this {@link WorkflowStatus}.
+	 */
+	public List<ServiceNode> getSelectedServices() {
+		return this.rootNode.getChildren();
+	}
+
+	/**
+	 * Add a {@link CloudServiceDefinition} and its corresponding
+	 * {@link ServiceConfiguration} on the root level of the services to execute by
+	 * this {@link WorkflowStatus}.
+	 * 
+	 * @param service The {@link CloudServiceDefinition} to add.
+	 * @param config  The {@link ServiceConfiguration} for the given
+	 *                {@link CloudServiceDefinition}. Can be <code>null</code>.
+	 */
+	public void addSelectedService(CloudServiceDefinition service, ServiceConfiguration config) {
+		this.rootNode.addChild(new ServiceNode(service, config));
 	}
 	
-	public void addSelectedService(CloudServiceDefinition service) {
-		this.selectedServices.add(service);
+	/**
+	 * Add a {@link CloudServiceDefinition} and its corresponding
+	 * {@link ServiceConfiguration} as a child of an already registered service node
+	 * denoted by the given parent key.
+	 * 
+	 * @param parentKey The key to identify an existing service node. A service path
+	 *                  can be represented as key by concatenating the keys with a
+	 *                  dot, e.g. migration.validation if validation is a child of
+	 *                  migration. Note: root should not be added as part of the key.
+	 * @param service   The {@link CloudServiceDefinition} to add.
+	 * @param config    The {@link ServiceConfiguration} for the given
+	 *                  {@link CloudServiceDefinition}. Can be <code>null</code>.
+	 */
+	public void addSelectedService(String parentKey, CloudServiceDefinition service, ServiceConfiguration config) {
+		String[] keys = parentKey.split("\\.");
+		ServiceNode parentNode = this.rootNode;
+		ServiceNode node = null;
+		for (int i = 0; i < keys.length; i++) {
+			String key = keys[i];
+			node = parentNode.getChildren().stream()
+					.filter(child -> child.getId().equals(key))
+					.findFirst()
+					.orElse(null);
+			
+			if (i == (keys.length - 1)) {
+				if (node != null) {
+					// we found a node, so simply add the child
+					node.addChild(new ServiceNode(service, config));
+				} else if (node == null) {
+					// we did not find the node, so probably a structural node should be added
+					node = new ServiceNode(key);
+					node.addChild(new ServiceNode(service, config));
+					parentNode.addChild(node);
+				}
+			}
+			
+			parentNode = node;
+		}
 	}
 	
-	public void removeSelectedService(CloudServiceDefinition service) {
-		this.selectedServices.remove(service);
+	/**
+	 * Adds all provided {@link ServiceNode}s on root level of this
+	 * {@link WorkflowStatus}. Used for copy mechanisms.
+	 * 
+	 * @param nodes The nodes to add on root level.
+	 */
+	public void addAllSelectedServices(List<ServiceNode> nodes) {
+		nodes.forEach(this.rootNode::addChild);
 	}
 	
-	public ServiceConfiguration getConfiguration(String key) {
-		return this.serviceConfigurations.get(key);
+	/**
+	 * Removes the given {@link CloudServiceDefinition} from the root level of this
+	 * {@link WorkflowStatus}.
+	 * 
+	 * @param service The {@link CloudServiceDefinition} to remove.
+	 */
+	public void removeSelectedService(CloudServiceDefinition service) {
+		this.rootNode.removeChild(service);
+	}
+
+	/**
+	 * Removes the given {@link CloudServiceDefinition} from the service node
+	 * denoted by the given parent key.
+	 * 
+	 * @param parentKey The key to identify the existing service node from which the
+	 *                  given service should be removed. A service path can be
+	 *                  represented as key by concatenating the keys with a dot,
+	 *                  e.g. migration.validation if validation is a child of
+	 *                  migration. Note: root should not be added as part of the
+	 *                  key.
+	 * @param service   The {@link CloudServiceDefinition} to remove.
+	 */
+	public void removeSelectedService(String parentKey, CloudServiceDefinition service) {
+		ServiceNode node = getServiceNode(parentKey);
+		if (node != null) {
+			node.removeChild(service);
+		}
 	}
 	
-	public HashMap<String, ServiceConfiguration> getConfigurations() {
-		return this.serviceConfigurations;
+	/**
+	 * Removes a service node denoted by the given key.
+	 * 
+	 * @param key The key to identify the service node to remove. A service path can
+	 *            be represented as key by concatenating the keys with a dot, e.g.
+	 *            migration.validation if validation is a child of migration. Note:
+	 *            root should not be added as part of the key.
+	 */
+	public void removeServiceNode(String key) {
+		// find the parent node
+		ServiceNode node = key.contains(".") ? getServiceNode(key.substring(0, key.lastIndexOf('.'))) : this.rootNode;
+		node.removeChild(key.substring(key.lastIndexOf('.') + 1));
 	}
 	
-	public void addConfiguration(String key, ServiceConfiguration config) {
-		this.serviceConfigurations.put(key, config);
+	/**
+	 * 
+	 * @param key The key for which the {@link CloudServiceDefinition} is requested. A
+	 *            key is typically the key of a {@link CloudServiceDefinition}. It
+	 *            is possible to provide a key path by concatenating keys with a
+	 *            dot, e.g. migration.validation in case validation is a child of
+	 *            migration.
+	 * @return The {@link CloudServiceDefinition} for the specified key or
+	 *         <code>null</code> if there is no {@link CloudServiceDefinition} for the
+	 *         specified key registered.
+	 */
+	public CloudServiceDefinition getService(String key) {
+		ServiceNode node = getServiceNode(key);
+		if (node != null) {
+			return node.getService();
+		}
+		return null;
 	}
 
-	public void removeConfiguration(String key) {
-		this.serviceConfigurations.remove(key);
+	/**
+	 * 
+	 * @param key The key for which the {@link ServiceConfiguration} is requested. A
+	 *            key is typically the key of a {@link CloudServiceDefinition}. It
+	 *            is possible to provide a key path by concatenating keys with a
+	 *            dot, e.g. migration.validation in case validation is a child of
+	 *            migration.
+	 * @return The {@link ServiceConfiguration} for the specified key or
+	 *         <code>null</code> if there is no {@link ServiceConfiguration} for the
+	 *         specified key registered.
+	 */
+	public ServiceConfiguration getConfiguration(String key) {
+		ServiceNode node = getServiceNode(key);
+		if (node != null) {
+			return node.getServiceConfiguration();
+		}
+		return null;
+	}
+	
+	private ServiceNode getServiceNode(String nodeKey) {
+		String[] keys = nodeKey.split("\\.");
+		ServiceNode parentNode = this.rootNode;
+		ServiceNode node = null;
+		for (int i = 0; i < keys.length; i++) {
+			String key = keys[i];
+			node = parentNode.getChildren().stream()
+					.filter(child -> child.getId().equals(key))
+					.findFirst()
+					.orElse(null);
+			
+			if (node == null) {
+				LOGGER.warn("Could not resolve key '{}' in nodeKey '{}'", key, nodeKey);
+				break;
+			}
+			
+			parentNode = node;
+		}
+		
+		return node;		
 	}
 	
 	public ArrayList<String> getMessages() {
@@ -126,8 +282,7 @@ public class WorkflowStatus {
 	}
 	
 	public void clear() {
-		this.selectedServices.clear();
-		this.serviceConfigurations.clear();
+		this.rootNode.clearChildren();
 		this.messages.clear();
 		this.errors.clear();
 		this.results.clear();
diff --git a/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowStatusDeserializer.java b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowStatusDeserializer.java
index 25a4aa2..fbdbadc 100644
--- a/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowStatusDeserializer.java
+++ b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowStatusDeserializer.java
@@ -14,7 +14,9 @@
 package org.eclipse.app4mc.cloud.manager;
 
 import java.io.IOException;
+import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
 
 import org.eclipse.app4mc.cloud.manager.administration.CloudServiceDefinition;
 
@@ -61,27 +63,7 @@ public class WorkflowStatusDeserializer extends StdDeserializer<WorkflowStatus>
         JsonNode services = node.get("services");
         if (services != null) {
         	services.fields().forEachRemaining(serviceField -> {
-        		// resolve the service
-        		String serviceKey = serviceField.getKey();
-		        CloudServiceDefinition csd = this.cloudServiceDefinitions.stream()
-						.filter(sd -> sd.getKey().equals(serviceKey))
-						.findFirst()
-						.orElse(null);
-		        if (csd != null) {
-		        	result.addSelectedService(csd);
-		        	
-		        	// resolve the service configuration
-		        	ServiceConfiguration config = WorkflowStatusHelper.getConfigurationForService(csd);
-		        	if (config != null) {
-		        		serviceField.getValue().fields().forEachRemaining(configField -> {
-		        			ServiceConfigurationParameter param = config.getParameter(configField.getKey());
-		        			if (param != null) {
-		        				param.setValue(configField.getValue().asText());
-		        			}
-		        		});
-		        		result.addConfiguration(serviceKey, config);
-		        	}
-		        }
+        		deserializeServiceNode(result, null, serviceField.getKey(), serviceField.getValue().fields());
         	});
         }
     	
@@ -111,4 +93,51 @@ public class WorkflowStatusDeserializer extends StdDeserializer<WorkflowStatus>
         
     	return result;
     }
+    
+    private void deserializeServiceNode(
+    		WorkflowStatus result, 
+    		String parentKey, 
+    		String serviceKey, 
+    		Iterator<Map.Entry<String, JsonNode>> fields) {
+    	
+        CloudServiceDefinition csd = this.cloudServiceDefinitions.stream()
+				.filter(sd -> sd.getKey().equals(serviceKey))
+				.findFirst()
+				.orElse(null);
+        if (csd != null) {
+        	// resolve the service configuration
+        	ServiceConfiguration config = WorkflowStatusHelper.getConfigurationForService(csd);
+        	
+        	// add the service to the workflow status so that the recursive calls work for nested service nodes
+        	if (parentKey == null) {
+        		result.addSelectedService(csd, config);
+        	} else {
+        		result.addSelectedService(parentKey, csd, config);
+        	}
+
+        	fields.forEachRemaining(configField -> {
+    			if (!configField.getValue().isContainerNode()) {
+    				// service parameter are simple values, no containers
+    				ServiceConfigurationParameter param = config.getParameter(configField.getKey());
+    				if (param != null) {
+    					param.setValue(configField.getValue().asText());
+    				}
+    			} else {
+    				// resolve nested services
+    				deserializeServiceNode(
+    						result, 
+    						parentKey != null ? parentKey + "." + serviceKey : serviceKey, 
+    						configField.getKey(), 
+    						configField.getValue().fields());
+    			}
+    		});
+        } else {
+        	// there is no service definition for the given key, so it is probably a structural node
+        	String nodeKey = parentKey != null ? parentKey + "." + serviceKey : serviceKey;
+        			
+			fields.forEachRemaining(serviceField -> {
+        		deserializeServiceNode(result, nodeKey, serviceField.getKey(), serviceField.getValue().fields());
+        	});
+        }
+    }
 }
diff --git a/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowStatusHelper.java b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowStatusHelper.java
index c815aa9..7b91cc7 100644
--- a/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowStatusHelper.java
+++ b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowStatusHelper.java
@@ -134,6 +134,60 @@ public final class WorkflowStatusHelper {
 	}
 	
 	/**
+	 * Helper method that adds default configuration parameter to a
+	 * {@link WorkflowStatus} in case they are not set.
+	 * 
+	 * @param workflowStatus The {@link WorkflowStatus} that should be enriched by
+	 *                       default configuration parameter.
+	 */
+	public static void addDefaultConfigurations(WorkflowStatus workflowStatus) {
+		for (ServiceNode node : workflowStatus.getSelectedServices()) {
+			addDefaultConfigurations(node);
+		}
+	}
+
+	/**
+	 * Helper method that adds default configuration parameter to a
+	 * {@link ServiceNode} in case they are not set.
+	 * 
+	 * @param node The {@link ServiceNode} that should be enriched by
+	 *                       default configuration parameter.
+	 */
+	public static void addDefaultConfigurations(ServiceNode node) {
+		// check if a configuration is already available
+		ServiceConfiguration configuration = node.getServiceConfiguration();
+		
+		ServiceConfigurationParameter timeOut = configuration.getParameter("timeout");
+		if (timeOut == null) {
+			timeOut = new ServiceConfigurationParameter();
+			timeOut.setName("Timeout (in ms)");
+			timeOut.setKey("timeout");
+			timeOut.setValue("60000");
+			if ("app4mc_sim".equals(node.getService().getKey())) {
+				timeOut.setValue("-1");
+			}
+			timeOut.setType("Long");
+			timeOut.setManagerParameter(true);
+			configuration.addParameter(timeOut);
+		}
+		
+		ServiceConfigurationParameter deleteResult = configuration.getParameter("deleteResult");
+		if (deleteResult == null) {
+			deleteResult = new ServiceConfigurationParameter();
+			deleteResult.setName("Delete result ");
+			deleteResult.setKey("deleteResult");
+			deleteResult.setValue("true");
+			deleteResult.setType("boolean");
+			deleteResult.setManagerParameter(true);
+			configuration.addParameter(deleteResult);
+		}
+		
+		for (ServiceNode child : node.getChildren()) {
+			addDefaultConfigurations(child);
+		}
+	}
+
+	/**
 	 * Serializes the given {@link WorkflowStatus} to the provided {@link File} as JSON.
 	 * 
 	 * @param ws   The {@link WorkflowStatus} to serialize.
diff --git a/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowStatusSerializer.java b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowStatusSerializer.java
index 5b4c41f..2f487bc 100644
--- a/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowStatusSerializer.java
+++ b/manager/src/main/java/org/eclipse/app4mc/cloud/manager/WorkflowStatusSerializer.java
@@ -52,20 +52,8 @@ public class WorkflowStatusSerializer extends StdSerializer<WorkflowStatus> {
 		
 		gen.writeFieldName("services");
 		gen.writeStartObject();
-		for (CloudServiceDefinition csd : value.getSelectedServices()) {
-			gen.writeFieldName(csd.getKey());
-			gen.writeStartObject();
-			
-			ServiceConfiguration configuration = value.getConfiguration(csd.getKey());
-			if (configuration != null) {
-				for (ServiceConfigurationParameter param : configuration.getParameterList()) {
-					if (param.getValue() != null) {
-						gen.writeObjectField(param.getKey(), param.getValue());
-					}
-				}
-			}
-			
-			gen.writeEndObject();
+		for (ServiceNode node : value.getSelectedServices()) {
+			serializeServiceNode(node, gen);
 		}
 		
 		gen.writeEndObject();
@@ -89,4 +77,28 @@ public class WorkflowStatusSerializer extends StdSerializer<WorkflowStatus> {
 		
 		gen.writeEndObject();
 	}
+	
+	private void serializeServiceNode(ServiceNode node, JsonGenerator gen) throws IOException {
+		gen.writeFieldName(node.getId());
+		gen.writeStartObject();
+
+		if (!node.isStructuralNode()) {
+			ServiceConfiguration configuration = node.getServiceConfiguration();
+			if (configuration != null) {
+				for (ServiceConfigurationParameter param : configuration.getParameterList()) {
+					if (param.getValue() != null) {
+						gen.writeObjectField(param.getKey(), param.getValue());
+					}
+				}
+			}
+		}
+		
+		if (!node.getChildren().isEmpty()) {
+			for (ServiceNode child : node.getChildren()) {
+				serializeServiceNode(child, gen);
+			}
+		}
+		
+		gen.writeEndObject();
+	}
 }
diff --git a/manager/src/main/resources/templates/selectedServices.html b/manager/src/main/resources/templates/selectedServices.html
index e195987..d8383ae 100644
--- a/manager/src/main/resources/templates/selectedServices.html
+++ b/manager/src/main/resources/templates/selectedServices.html
@@ -7,16 +7,16 @@
 <body>
     <div th:fragment="servicesList" id="selectedServices" th:object="${workflowStatus}">
 		<ul class="list-group"> 
-			<li th:each="selected : ${workflowStatus.selectedServices}" class="list-group-item d-flex justify-content-between" th:classappend="*{uuid != null} ? disabled_service : ''">
+			<li th:each="selected : *{selectedServices}" class="list-group-item d-flex justify-content-between" th:classappend="*{uuid != null} ? disabled_service : ''">
 				<p 
 					class="p-0 flex-grow-1 plist" 
-					th:text="${selected.name}" 
-					th:title="${selected.description}"
+					th:text="${selected.service.name}" 
+					th:title="${selected.service.description}"
 					data-toggle="tooltip"
 					th:classappend="*{uuid != null} ? disabled_service : ''">Service</p> 
 				<a 
 					th:if="*{uuid == null}"
-					th:attr="onclick=|removeSelectedServices('${selected.key}')|" 
+					th:attr="onclick=|removeSelectedServices('${selected.service.key}')|" 
 					class="btn btn-primary btn-sm btn-rmv">
 					<i class="fas fa-times"></i>
 				</a>
@@ -36,17 +36,17 @@
 		    </option>
 		</select><br>
 		
-		<div th:if="not *{configurations.isEmpty()}">
-			<div th:each="config : *{configurations}" class="mb-3">
-				<h4 th:text="${config.value.serviceName + ' Configuration'}">Config</h4>
-				<div th:each="parameter, parameterStatus : ${config.value.parameterList}">
+		<div th:if="not *{selectedServices.isEmpty()}">
+			<div th:each="node, nodeStatus : *{selectedServices}" class="mb-3">
+				<h4 th:text="${node.service.name + ' Configuration'}">Config</h4>
+				<div th:each="parameter, parameterStatus : ${node.serviceConfiguration.parameterList}">
 					<!-- single non-boolean value -->
 					<div th:if="${parameter.cardinality == 'single' and parameter.type != 'boolean' and parameter.possibleValues.isEmpty()}">
 						<label class="form-check-label" th:text="${parameter.name}">Label</label>
 						<input 
 							class="form-control" 
 							type="text" 
-							th:field="*{configurations[__${config.key}__].parameterList[__${parameterStatus.index}__].value}"
+							th:field="*{selectedServices[__${nodeStatus.index}__].serviceConfiguration.parameterList[__${parameterStatus.index}__].value}"
 							th:disabled="*{uuid != null}"/>
 					</div>
 					<!-- single boolean value -->
@@ -54,7 +54,7 @@
 						<input
 							class="form-check-input"
 							type="checkbox"
-							th:field="*{configurations[__${config.key}__].parameterList[__${parameterStatus.index}__].value}"
+							th:field="*{selectedServices[__${nodeStatus.index}__].serviceConfiguration.parameterList[__${parameterStatus.index}__].value}"
 							th:value="true"
 							th:disabled="*{uuid != null}">
 						<label class="form-check-label" th:text="${parameter.name}" th:for="${parameter.key}">Label</label>
@@ -65,7 +65,7 @@
 						<div th:each="pv : ${parameter.possibleValues}" class="form-check">
 							<input
 								type="checkbox"
-								th:field="*{configurations[__${config.key}__].parameterList[__${parameterStatus.index}__].value}"
+								th:field="*{selectedServices[__${nodeStatus.index}__].serviceConfiguration.parameterList[__${parameterStatus.index}__].value}"
 								th:value="${pv}"
 								th:disabled="*{uuid != null}">
 							<label class="form-check-label" th:text="${pv}">Value</label>
@@ -76,7 +76,7 @@
 						<label th:text="${parameter.name}">Label</label>
 						<select
 							class="custom-select"
-							th:field="*{configurations[__${config.key}__].parameterList[__${parameterStatus.index}__].value}"
+							th:field="*{selectedServices[__${nodeStatus.index}__].serviceConfiguration.parameterList[__${parameterStatus.index}__].value}"
 							th:disabled="*{uuid != null}">
 							<option value=""></option>
 						    <option 
diff --git a/manager/src/test/java/org/eclipse/app4mc/cloud/manager/WorkflowStatusHelperTest.java b/manager/src/test/java/org/eclipse/app4mc/cloud/manager/WorkflowStatusHelperTest.java
index c89cdcd..9d15843 100644
--- a/manager/src/test/java/org/eclipse/app4mc/cloud/manager/WorkflowStatusHelperTest.java
+++ b/manager/src/test/java/org/eclipse/app4mc/cloud/manager/WorkflowStatusHelperTest.java
@@ -16,11 +16,13 @@ package org.eclipse.app4mc.cloud.manager;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
+import java.util.List;
 
 import org.eclipse.app4mc.cloud.manager.administration.CloudServiceDefinition;
 import org.junit.jupiter.api.BeforeAll;
@@ -33,38 +35,149 @@ import com.fasterxml.jackson.databind.module.SimpleModule;
 
 public class WorkflowStatusHelperTest {
 
-	private static String JSON_STRING;
+	private static String JSON_STRING_SIMPLE_CHAIN;
+	private static String JSON_STRING_ALL_NESTED;
+	private static String JSON_STRING_STRUCTURED_NESTED;
 	
+	private static CloudServiceDefinition MIGRATION = new CloudServiceDefinition(
+			"migration", 
+			"Migration", 
+			"http://localhost:8080/app4mc/converter/", 
+			"Migrates an input model file to model version 0.9.9");
+	private static CloudServiceDefinition VALIDATION = new CloudServiceDefinition(
+			"validation", 
+			"Validation", 
+			"http://localhost:8181/app4mc/validation/", 
+			"Validates the input model file");
+
+	private static CloudServiceDefinition LABEL_CORE = new CloudServiceDefinition(
+			"label_core_interpreter", 
+			"Label per Core Interpreter", 
+			"http://localhost:8084/app4mc/interpreter/label-per-core/", 
+			"Parses an Amalthea model to inspect label access operations per core");
+	private static CloudServiceDefinition LABEL_MEMORY = new CloudServiceDefinition(
+			"label_memory_interpreter", 
+			"Label per Memory Interpreter", 
+			"http://localhost:8084/app4mc/interpreter/label-per-memory/", 
+			"Parses an Amalthea model to inspect label access operations per memory");
+	private static CloudServiceDefinition LABEL_TASK = new CloudServiceDefinition(
+			"label_task_interpreter", 
+			"Label per Task Interpreter", 
+			"http://localhost:8084/app4mc/interpreter/label-per-task/", 
+			"Parses an Amalthea model to inspect label access operations per task");
+	private static CloudServiceDefinition LABEL_SIZE = new CloudServiceDefinition(
+			"label_size_interpreter", 
+			"Label Size Interpreter", 
+			"http://localhost:8084/app4mc/interpreter/label-size/", 
+			"Parses an Amalthea model to inspect the number of labels grouped by size");
+	
+	private static CloudServiceDefinition CHART_VISUALIZER = new CloudServiceDefinition(
+			"chart_visualizer", 
+			"Chart Visualizer", 
+			"http://localhost:8083/app4mc/visualization/barchart/", 
+			"Visualization of interpreter results");
+
 	@BeforeAll
 	public static void beforeAll() {
-		StringBuilder builder = new StringBuilder();
-		builder.append("{").append(System.lineSeparator());
-		builder.append("  \"name\" : \"Test Name\",").append(System.lineSeparator());
-		builder.append("  \"uuid\" : \"1234\",").append(System.lineSeparator());
-		builder.append("  \"services\" : {").append(System.lineSeparator());
-		builder.append("    \"label_core_interpreter\" : {").append(System.lineSeparator());
-		builder.append("      \"timeout\" : \"360000\",").append(System.lineSeparator());
-		builder.append("      \"deleteResult\" : \"false\"").append(System.lineSeparator());
-		builder.append("    },").append(System.lineSeparator());
-		builder.append("    \"chart_visualizer\" : { }").append(System.lineSeparator());
-		builder.append("  },").append(System.lineSeparator());
-		builder.append("  \"cancelled\" : false,").append(System.lineSeparator());
-		builder.append("  \"done\" : true,").append(System.lineSeparator());
-		builder.append("  \"messages\" : [ \"Message One\", \"Message Two\", \"Message Three\" ],").append(System.lineSeparator());
-		builder.append("  \"errors\" : [ ],").append(System.lineSeparator());
-		builder.append("  \"results\" : {").append(System.lineSeparator());
-		builder.append("    \"Label per Core Interpreter Result\" : \"_label per core interpreter/nodesdata.json\",").append(System.lineSeparator());
-		builder.append("    \"Chart Visualizer Result\" : \"_chart visualizer/barchart.html\"").append(System.lineSeparator());
-		builder.append("  }").append(System.lineSeparator());
-		builder.append("}");
-		
-		JSON_STRING = builder.toString();
+		StringBuilder simpleChainBuilder = new StringBuilder();
+		simpleChainBuilder.append("{").append(System.lineSeparator());
+		simpleChainBuilder.append("  \"name\" : \"Test Name\",").append(System.lineSeparator());
+		simpleChainBuilder.append("  \"uuid\" : \"1234\",").append(System.lineSeparator());
+		simpleChainBuilder.append("  \"services\" : {").append(System.lineSeparator());
+		simpleChainBuilder.append("    \"label_core_interpreter\" : {").append(System.lineSeparator());
+		simpleChainBuilder.append("      \"timeout\" : \"360000\",").append(System.lineSeparator());
+		simpleChainBuilder.append("      \"deleteResult\" : \"false\"").append(System.lineSeparator());
+		simpleChainBuilder.append("    },").append(System.lineSeparator());
+		simpleChainBuilder.append("    \"chart_visualizer\" : { }").append(System.lineSeparator());
+		simpleChainBuilder.append("  },").append(System.lineSeparator());
+		simpleChainBuilder.append("  \"cancelled\" : false,").append(System.lineSeparator());
+		simpleChainBuilder.append("  \"done\" : true,").append(System.lineSeparator());
+		simpleChainBuilder.append("  \"messages\" : [ \"Message One\", \"Message Two\", \"Message Three\" ],").append(System.lineSeparator());
+		simpleChainBuilder.append("  \"results\" : {").append(System.lineSeparator());
+		simpleChainBuilder.append("    \"Label per Core Interpreter Result\" : \"_label per core interpreter/nodesdata.json\",").append(System.lineSeparator());
+		simpleChainBuilder.append("    \"Chart Visualizer Result\" : \"_chart visualizer/barchart.html\"").append(System.lineSeparator());
+		simpleChainBuilder.append("  }").append(System.lineSeparator());
+		simpleChainBuilder.append("}");
+		
+		JSON_STRING_SIMPLE_CHAIN = simpleChainBuilder.toString();
+
+		StringBuilder allNestedBuilder = new StringBuilder();
+		allNestedBuilder.append("{").append(System.lineSeparator());
+		allNestedBuilder.append("  \"services\" : {").append(System.lineSeparator());
+		allNestedBuilder.append("    \"migration\" : {").append(System.lineSeparator());
+		allNestedBuilder.append("      \"timeout\" : \"60000\",").append(System.lineSeparator());
+		allNestedBuilder.append("      \"deleteResult\" : \"true\",").append(System.lineSeparator());
+		allNestedBuilder.append("      \"validation\" : {").append(System.lineSeparator());
+		allNestedBuilder.append("        \"timeout\" : \"60000\",").append(System.lineSeparator());
+		allNestedBuilder.append("        \"deleteResult\" : \"true\",").append(System.lineSeparator());
+		allNestedBuilder.append("        \"label_core_interpreter\" : { }").append(System.lineSeparator());
+		allNestedBuilder.append("      }").append(System.lineSeparator());
+		allNestedBuilder.append("    }").append(System.lineSeparator());
+		allNestedBuilder.append("  }").append(System.lineSeparator());
+		allNestedBuilder.append("}");
+		
+		JSON_STRING_ALL_NESTED = allNestedBuilder.toString();
+		
+		StringBuilder structuredNestedBuilder = new StringBuilder();
+		structuredNestedBuilder.append("{").append(System.lineSeparator());
+		structuredNestedBuilder.append("  \"name\" : \"Test Name\",").append(System.lineSeparator());
+		structuredNestedBuilder.append("  \"uuid\" : \"1234\",").append(System.lineSeparator());
+		structuredNestedBuilder.append("  \"services\" : {").append(System.lineSeparator());
+		structuredNestedBuilder.append("    \"migration\" : {").append(System.lineSeparator());
+		structuredNestedBuilder.append("      \"timeout\" : \"60000\",").append(System.lineSeparator());
+		structuredNestedBuilder.append("      \"deleteResult\" : \"true\"").append(System.lineSeparator());
+		structuredNestedBuilder.append("    },").append(System.lineSeparator());
+		structuredNestedBuilder.append("    \"validation\" : {").append(System.lineSeparator());
+		structuredNestedBuilder.append("      \"timeout\" : \"60000\",").append(System.lineSeparator());
+		structuredNestedBuilder.append("      \"deleteResult\" : \"true\",").append(System.lineSeparator());
+		structuredNestedBuilder.append("      \"profiles\" : \"Amalthea Standard Validations\",").append(System.lineSeparator());
+		structuredNestedBuilder.append("      \"label_core_chart\" : {").append(System.lineSeparator());
+		structuredNestedBuilder.append("        \"label_core_interpreter\" : {").append(System.lineSeparator());
+		structuredNestedBuilder.append("          \"timeout\" : \"360000\",").append(System.lineSeparator());
+		structuredNestedBuilder.append("          \"deleteResult\" : \"false\"").append(System.lineSeparator());
+		structuredNestedBuilder.append("        },").append(System.lineSeparator());
+		structuredNestedBuilder.append("        \"chart_visualizer\" : { }").append(System.lineSeparator());
+		structuredNestedBuilder.append("      },").append(System.lineSeparator());
+		structuredNestedBuilder.append("      \"label_memory_chart\" : {").append(System.lineSeparator());
+		structuredNestedBuilder.append("        \"label_memory_interpreter\" : {").append(System.lineSeparator());
+		structuredNestedBuilder.append("          \"timeout\" : \"60000\",").append(System.lineSeparator());
+		structuredNestedBuilder.append("          \"deleteResult\" : \"true\"").append(System.lineSeparator());
+		structuredNestedBuilder.append("        },").append(System.lineSeparator());
+		structuredNestedBuilder.append("        \"chart_visualizer\" : { }").append(System.lineSeparator());
+		structuredNestedBuilder.append("      },").append(System.lineSeparator());
+		structuredNestedBuilder.append("      \"label_task_chart\" : {").append(System.lineSeparator());
+		structuredNestedBuilder.append("        \"label_task_interpreter\" : {").append(System.lineSeparator());
+		structuredNestedBuilder.append("          \"timeout\" : \"60000\",").append(System.lineSeparator());
+		structuredNestedBuilder.append("          \"deleteResult\" : \"true\"").append(System.lineSeparator());
+		structuredNestedBuilder.append("        },").append(System.lineSeparator());
+		structuredNestedBuilder.append("        \"chart_visualizer\" : { }").append(System.lineSeparator());
+		structuredNestedBuilder.append("      },").append(System.lineSeparator());
+		structuredNestedBuilder.append("      \"label_size_chart\" : {").append(System.lineSeparator());
+		structuredNestedBuilder.append("        \"label_size_interpreter\" : {").append(System.lineSeparator());
+		structuredNestedBuilder.append("          \"timeout\" : \"60000\",").append(System.lineSeparator());
+		structuredNestedBuilder.append("          \"deleteResult\" : \"true\"").append(System.lineSeparator());
+		structuredNestedBuilder.append("        },").append(System.lineSeparator());
+		structuredNestedBuilder.append("        \"chart_visualizer\" : { }").append(System.lineSeparator());
+		structuredNestedBuilder.append("      }").append(System.lineSeparator());
+		structuredNestedBuilder.append("    }").append(System.lineSeparator());
+		structuredNestedBuilder.append("  },").append(System.lineSeparator());
+		structuredNestedBuilder.append("  \"cancelled\" : false,").append(System.lineSeparator());
+		structuredNestedBuilder.append("  \"done\" : true,").append(System.lineSeparator());
+		structuredNestedBuilder.append("  \"messages\" : [ \"Message One\", \"Message Two\", \"Message Three\" ],").append(System.lineSeparator());
+		structuredNestedBuilder.append("  \"results\" : {").append(System.lineSeparator());
+		structuredNestedBuilder.append("    \"Label per Core Interpreter Result\" : \"_label per core interpreter/nodesdata.json\",").append(System.lineSeparator());
+		structuredNestedBuilder.append("    \"Chart Visualizer Result\" : \"_chart visualizer/barchart.html\"").append(System.lineSeparator());
+		structuredNestedBuilder.append("  }").append(System.lineSeparator());
+		structuredNestedBuilder.append("}");
+		
+		JSON_STRING_STRUCTURED_NESTED = structuredNestedBuilder.toString();
 	}
 	
 	@Test
 	public void shouldSerializeWorkflowStatus() throws JsonProcessingException {
-		CloudServiceDefinition service1 = new CloudServiceDefinition("label_core_interpreter", "Label per Core Interpreter", "http://localhost:8080/test", "BlaBlaBla");
-		CloudServiceDefinition service2 = new CloudServiceDefinition("chart_visualizer", "Chart Visualizer", "http://localhost:8080/another", "FuBar");
+		ServiceConfiguration config1 = WorkflowStatusHelper.getConfigurationForService(LABEL_CORE);
+		config1.getParameter("timeout").setValue("360000");
+		config1.getParameter("deleteResult").setValue("false");
 
 		ObjectMapper mapper = new ObjectMapper();
 		
@@ -73,14 +186,9 @@ public class WorkflowStatusHelperTest {
 		ws.setUuid("1234");
 		ws.done();
 		
-		ws.addSelectedService(service1);
-		ws.addSelectedService(service2);
+		ws.addSelectedService(LABEL_CORE, config1);
+		ws.addSelectedService(CHART_VISUALIZER, null);
 		
-		ServiceConfiguration config1 = WorkflowStatusHelper.getConfigurationForService(service1);
-		config1.getParameter("timeout").setValue("360000");
-		config1.getParameter("deleteResult").setValue("false");
-		ws.addConfiguration(service1.getKey(), config1);
-
 		ws.addMessage("Message One");
 		ws.addMessage("Message Two");
 		ws.addMessage("Message Three");
@@ -90,20 +198,17 @@ public class WorkflowStatusHelperTest {
 		
 		String json = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(ws);
 		
-		assertEquals(JSON_STRING, json);
+		assertEquals(JSON_STRING_SIMPLE_CHAIN, json);
 	}
 	
 	@Test
 	public void shouldDeserializeWorkflowStatus() throws JsonMappingException, JsonProcessingException {
-		CloudServiceDefinition service1 = new CloudServiceDefinition("label_core_interpreter", "Label per Core Interpreter", "http://localhost:8080/test", "BlaBlaBla");
-		CloudServiceDefinition service2 = new CloudServiceDefinition("chart_visualizer", "Chart Visualizer", "http://localhost:8080/another", "FuBar");
-
 		ObjectMapper mapper = new ObjectMapper();
 		SimpleModule module = new SimpleModule();
-		module.addDeserializer(WorkflowStatus.class, new WorkflowStatusDeserializer(Arrays.asList(service1, service2)));
+		module.addDeserializer(WorkflowStatus.class, new WorkflowStatusDeserializer(Arrays.asList(LABEL_CORE, CHART_VISUALIZER)));
 		mapper.registerModule(module);
 		
-		WorkflowStatus ws = mapper.readValue(JSON_STRING, WorkflowStatus.class);
+		WorkflowStatus ws = mapper.readValue(JSON_STRING_SIMPLE_CHAIN, WorkflowStatus.class);
 		
 		assertEquals("Test Name", ws.getName());
 		assertEquals("1234", ws.getUuid());
@@ -127,24 +232,281 @@ public class WorkflowStatusHelperTest {
 		assertEquals("_label per core interpreter/nodesdata.json", results.get("Label per Core Interpreter Result"));
 		assertEquals("_chart visualizer/barchart.html", results.get("Chart Visualizer Result"));
 		
-		ArrayList<CloudServiceDefinition> services = ws.getSelectedServices();
+		List<ServiceNode> services = ws.getSelectedServices();
 		assertNotNull(services);
 		assertEquals(2, services.size());
-		assertEquals("label_core_interpreter", services.get(0).getKey());
-		assertEquals("Label per Core Interpreter", services.get(0).getName());
-		assertEquals("http://localhost:8080/test", services.get(0).getBaseUrl());
-		assertEquals("BlaBlaBla", services.get(0).getDescription());
-		assertEquals("chart_visualizer", services.get(1).getKey());
-		assertEquals("Chart Visualizer", services.get(1).getName());
-		assertEquals("http://localhost:8080/another", services.get(1).getBaseUrl());
-		assertEquals("FuBar", services.get(1).getDescription());
-		
-		HashMap<String,ServiceConfiguration> configurations = ws.getConfigurations();
-		assertEquals(2, configurations.size());
-		assertEquals("360000", configurations.get("label_core_interpreter").getParameter("timeout").getValue());
-		assertEquals("false", configurations.get("label_core_interpreter").getParameter("deleteResult").getValue());
+		assertEquals("label_core_interpreter", services.get(0).getService().getKey());
+		assertEquals("Label per Core Interpreter", services.get(0).getService().getName());
+		assertEquals("http://localhost:8084/app4mc/interpreter/label-per-core/", services.get(0).getService().getBaseUrl());
+		assertEquals("Parses an Amalthea model to inspect label access operations per core", services.get(0).getService().getDescription());
+		assertEquals(0, services.get(0).getChildren().size());
+		assertEquals("chart_visualizer", services.get(1).getService().getKey());
+		assertEquals("Chart Visualizer", services.get(1).getService().getName());
+		assertEquals("http://localhost:8083/app4mc/visualization/barchart/", services.get(1).getService().getBaseUrl());
+		assertEquals("Visualization of interpreter results", services.get(1).getService().getDescription());
+		assertEquals(0, services.get(1).getChildren().size());
+		
+		assertEquals("360000", ws.getConfiguration("label_core_interpreter").getParameter("timeout").getValue());
+		assertEquals("false", ws.getConfiguration("label_core_interpreter").getParameter("deleteResult").getValue());
 		// check that the default configuration set as no configuration is in the JSON
-		assertEquals("60000", configurations.get("chart_visualizer").getParameter("timeout").getValue());
-		assertEquals("true", configurations.get("chart_visualizer").getParameter("deleteResult").getValue());
+		assertEquals("60000", ws.getConfiguration("chart_visualizer").getParameter("timeout").getValue());
+		assertEquals("true", ws.getConfiguration("chart_visualizer").getParameter("deleteResult").getValue());
+	}
+	
+	
+	@Test
+	public void shouldSerializeAllNestedServices() throws JsonProcessingException {
+		WorkflowStatus ws = new WorkflowStatus();
+		ws.addSelectedService(MIGRATION, WorkflowStatusHelper.getConfigurationForService(MIGRATION));
+		ws.addSelectedService("migration", VALIDATION, WorkflowStatusHelper.getConfigurationForService(VALIDATION));
+		ws.addSelectedService("migration.validation", LABEL_CORE, null);
+		
+		ObjectMapper mapper = new ObjectMapper();
+		String json = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(ws);
+		
+		assertEquals(JSON_STRING_ALL_NESTED, json);
+	}
+
+	@Test
+	public void shouldDeserializeAllNestedServices() throws JsonProcessingException {
+		ObjectMapper mapper = new ObjectMapper();
+		SimpleModule module = new SimpleModule();
+		module.addDeserializer(WorkflowStatus.class, new WorkflowStatusDeserializer(Arrays.asList(MIGRATION, VALIDATION, LABEL_CORE)));
+		mapper.registerModule(module);
+		
+		WorkflowStatus ws = mapper.readValue(JSON_STRING_ALL_NESTED, WorkflowStatus.class);
+
+		List<ServiceNode> services = ws.getSelectedServices();
+		assertNotNull(services);
+		assertEquals(1, services.size());
+		assertEquals("migration", services.get(0).getService().getKey());
+		assertEquals(1, services.get(0).getChildren().size());
+
+		ServiceNode child = services.get(0).getChildren().get(0);
+		assertEquals("validation", child.getService().getKey());
+		assertEquals(1, child.getChildren().size());
+		
+		child = child.getChildren().get(0);
+		assertEquals("label_core_interpreter", child.getService().getKey());
+		assertEquals(0, child.getChildren().size());
+	}
+	
+	@Test
+	public void shouldSerializeWorkflowStatusStructuredNested() throws JsonProcessingException {
+		ServiceConfiguration validationConfig = WorkflowStatusHelper.getConfigurationForService(VALIDATION);
+		ServiceConfigurationParameter validationProfiles = new ServiceConfigurationParameter();
+		validationProfiles.setName("Validation profiles");
+		validationProfiles.setKey("profiles");
+		validationProfiles.setType("String");
+		validationProfiles.setCardinality("multiple");
+		validationProfiles.setPossibleValues(Arrays.asList("Amalthea Standard Validations", "INCHRON Validations"));
+		validationConfig.addParameter(validationProfiles);
+
+		validationConfig.getParameter("profiles").setValue("Amalthea Standard Validations");
+
+		ServiceConfiguration labelCoreConfig = WorkflowStatusHelper.getConfigurationForService(LABEL_CORE);
+		labelCoreConfig.getParameter("timeout").setValue("360000");
+		labelCoreConfig.getParameter("deleteResult").setValue("false");
+
+		ObjectMapper mapper = new ObjectMapper();
+		
+		WorkflowStatus ws = new WorkflowStatus();
+		ws.setName("Test Name");
+		ws.setUuid("1234");
+		ws.done();
+		
+		ws.addSelectedService(MIGRATION, WorkflowStatusHelper.getConfigurationForService(MIGRATION));
+		ws.addSelectedService(VALIDATION, validationConfig);
+		
+		// create structural nodes for sub chains
+		ws.addSelectedService("validation.label_core_chart", LABEL_CORE, labelCoreConfig);
+		ws.addSelectedService("validation.label_core_chart", CHART_VISUALIZER, null);
+
+		ws.addSelectedService("validation.label_memory_chart", LABEL_MEMORY, WorkflowStatusHelper.getConfigurationForService(LABEL_MEMORY));
+		ws.addSelectedService("validation.label_memory_chart", CHART_VISUALIZER, null);
+
+		ws.addSelectedService("validation.label_task_chart", LABEL_TASK, WorkflowStatusHelper.getConfigurationForService(LABEL_TASK));
+		ws.addSelectedService("validation.label_task_chart", CHART_VISUALIZER, null);
+		
+		ws.addSelectedService("validation.label_size_chart", LABEL_SIZE, WorkflowStatusHelper.getConfigurationForService(LABEL_SIZE));
+		ws.addSelectedService("validation.label_size_chart", CHART_VISUALIZER, null);
+		
+		
+		ws.addMessage("Message One");
+		ws.addMessage("Message Two");
+		ws.addMessage("Message Three");
+		
+		ws.addResult("Label per Core Interpreter Result", "_label per core interpreter/nodesdata.json");
+		ws.addResult("Chart Visualizer Result", "_chart visualizer/barchart.html");
+		
+		String json = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(ws);
+		
+		assertEquals(JSON_STRING_STRUCTURED_NESTED, json);
+	}
+
+	@Test
+	public void shouldDeserializeWorkflowStatusStructuredNested() throws JsonProcessingException {
+		ObjectMapper mapper = new ObjectMapper();
+		SimpleModule module = new SimpleModule();
+		module.addDeserializer(
+				WorkflowStatus.class, 
+				new WorkflowStatusDeserializer(Arrays.asList(MIGRATION, VALIDATION, LABEL_CORE, LABEL_MEMORY, LABEL_TASK, LABEL_SIZE, CHART_VISUALIZER)));
+		mapper.registerModule(module);
+		
+		WorkflowStatus ws = mapper.readValue(JSON_STRING_STRUCTURED_NESTED, WorkflowStatus.class);
+
+		List<ServiceNode> services = ws.getSelectedServices();
+		assertNotNull(services);
+		assertEquals(2, services.size());
+		assertEquals("migration", services.get(0).getService().getKey());
+		assertEquals(0, services.get(0).getChildren().size());
+
+		assertEquals("validation", services.get(1).getService().getKey());
+		// validation has 4 structure nodes for 4 different sub process chains
+		assertEquals(4, services.get(1).getChildren().size());
+
+		ServiceNode child = services.get(1).getChildren().get(0);
+		assertTrue(child.isStructuralNode(), "child is not a structural node");
+		assertEquals("label_core_chart", child.getId());
+		assertEquals(2, child.getChildren().size());
+		
+		ServiceNode subChild = child.getChildren().get(0);
+		assertFalse(subChild.isStructuralNode(), "child is a structural node");
+		assertNotNull(subChild.getService());
+		assertEquals("label_core_interpreter", subChild.getId());
+		assertEquals("label_core_interpreter", subChild.getService().getKey());
+		assertEquals("360000", subChild.getServiceConfiguration().getParameter("timeout").getValue());
+		assertEquals("false", subChild.getServiceConfiguration().getParameter("deleteResult").getValue());
+
+		subChild = child.getChildren().get(1);
+		assertFalse(subChild.isStructuralNode(), "child is a structural node");
+		assertNotNull(subChild.getService());
+		assertEquals("chart_visualizer", subChild.getId());
+		assertEquals("chart_visualizer", subChild.getService().getKey());
+		assertEquals("60000", subChild.getServiceConfiguration().getParameter("timeout").getValue());
+		assertEquals("true", subChild.getServiceConfiguration().getParameter("deleteResult").getValue());
+		
+		child = services.get(1).getChildren().get(1);
+		assertTrue(child.isStructuralNode(), "child is not a structural node");
+		assertEquals("label_memory_chart", child.getId());
+		assertEquals(2, child.getChildren().size());
+		
+		subChild = child.getChildren().get(0);
+		assertFalse(subChild.isStructuralNode(), "child is a structural node");
+		assertNotNull(subChild.getService());
+		assertEquals("label_memory_interpreter", subChild.getId());
+		assertEquals("label_memory_interpreter", subChild.getService().getKey());
+		assertEquals("60000", subChild.getServiceConfiguration().getParameter("timeout").getValue());
+		assertEquals("true", subChild.getServiceConfiguration().getParameter("deleteResult").getValue());
+		
+		subChild = child.getChildren().get(1);
+		assertFalse(subChild.isStructuralNode(), "child is a structural node");
+		assertNotNull(subChild.getService());
+		assertEquals("chart_visualizer", subChild.getId());
+		assertEquals("chart_visualizer", subChild.getService().getKey());
+		assertEquals("60000", subChild.getServiceConfiguration().getParameter("timeout").getValue());
+		assertEquals("true", subChild.getServiceConfiguration().getParameter("deleteResult").getValue());
+		
+		child = services.get(1).getChildren().get(2);
+		assertTrue(child.isStructuralNode(), "child is not a structural node");
+		assertEquals("label_task_chart", child.getId());
+		assertEquals(2, child.getChildren().size());
+		
+		subChild = child.getChildren().get(0);
+		assertFalse(subChild.isStructuralNode(), "child is a structural node");
+		assertNotNull(subChild.getService());
+		assertEquals("label_task_interpreter", subChild.getId());
+		assertEquals("label_task_interpreter", subChild.getService().getKey());
+		assertEquals("60000", subChild.getServiceConfiguration().getParameter("timeout").getValue());
+		assertEquals("true", subChild.getServiceConfiguration().getParameter("deleteResult").getValue());
+		
+		subChild = child.getChildren().get(1);
+		assertFalse(subChild.isStructuralNode(), "child is a structural node");
+		assertNotNull(subChild.getService());
+		assertEquals("chart_visualizer", subChild.getId());
+		assertEquals("chart_visualizer", subChild.getService().getKey());
+		assertEquals("60000", subChild.getServiceConfiguration().getParameter("timeout").getValue());
+		assertEquals("true", subChild.getServiceConfiguration().getParameter("deleteResult").getValue());
+		
+		child = services.get(1).getChildren().get(3);
+		assertTrue(child.isStructuralNode(), "child is not a structural node");
+		assertEquals("label_size_chart", child.getId());
+		assertEquals(2, child.getChildren().size());
+		
+		subChild = child.getChildren().get(0);
+		assertFalse(subChild.isStructuralNode(), "child is a structural node");
+		assertNotNull(subChild.getService());
+		assertEquals("label_size_interpreter", subChild.getId());
+		assertEquals("label_size_interpreter", subChild.getService().getKey());
+		assertEquals("60000", subChild.getServiceConfiguration().getParameter("timeout").getValue());
+		assertEquals("true", subChild.getServiceConfiguration().getParameter("deleteResult").getValue());
+		
+		subChild = child.getChildren().get(1);
+		assertFalse(subChild.isStructuralNode(), "child is a structural node");
+		assertNotNull(subChild.getService());
+		assertEquals("chart_visualizer", subChild.getId());
+		assertEquals("chart_visualizer", subChild.getService().getKey());
+		assertEquals("60000", subChild.getServiceConfiguration().getParameter("timeout").getValue());
+		assertEquals("true", subChild.getServiceConfiguration().getParameter("deleteResult").getValue());
+	}
+
+	@Test
+	public void shouldOperateOnWorkflowStatusStructuredNested() throws JsonProcessingException {
+		ObjectMapper mapper = new ObjectMapper();
+		SimpleModule module = new SimpleModule();
+		module.addDeserializer(
+				WorkflowStatus.class, 
+				new WorkflowStatusDeserializer(Arrays.asList(MIGRATION, VALIDATION, LABEL_CORE, LABEL_MEMORY, LABEL_TASK, LABEL_SIZE, CHART_VISUALIZER)));
+		mapper.registerModule(module);
+		
+		WorkflowStatus ws = mapper.readValue(JSON_STRING_STRUCTURED_NESTED, WorkflowStatus.class);
+		
+		// test direct access on services via workflow status using concatenated keys
+		CloudServiceDefinition service = ws.getService("validation.label_core_chart.chart_visualizer");
+		assertEquals(CHART_VISUALIZER, service);
+		service = ws.getService("validation.label_memory_chart.chart_visualizer");
+		assertEquals(CHART_VISUALIZER, service);
+		service = ws.getService("validation.label_task_chart.chart_visualizer");
+		assertEquals(CHART_VISUALIZER, service);
+		service = ws.getService("validation.label_size_chart.chart_visualizer");
+		assertEquals(CHART_VISUALIZER, service);
+		
+		assertNull(ws.getService("some.stupid.key"));
+		
+		ServiceConfiguration config = ws.getConfiguration("validation.label_core_chart.label_core_interpreter");
+		assertEquals("360000", config.getParameter("timeout").getValue());
+		assertEquals("false", config.getParameter("deleteResult").getValue());
+		
+		assertNull(ws.getConfiguration("some.stupid.key"));
+		
+		List<ServiceNode> services = ws.getSelectedServices();
+		assertNotNull(services);
+		assertEquals(2, services.size());
+		assertEquals("migration", services.get(0).getService().getKey());
+
+		// remove migration on root level
+		ws.removeSelectedService(MIGRATION);
+		
+		services = ws.getSelectedServices();
+		assertNotNull(services);
+		assertEquals(1, services.size());
+		assertEquals("validation", services.get(0).getService().getKey());
+		assertEquals(4, services.get(0).getChildren().size());
+		
+		// remove structural node label_task_chart
+		ws.removeServiceNode("validation.label_task_chart");
+		
+		assertEquals(3, services.get(0).getChildren().size());
+		
+		ServiceNode serviceNode = services.get(0).getChildren().get(2);
+		assertTrue(serviceNode.isStructuralNode());
+		assertEquals("label_size_chart", serviceNode.getId());
+		assertEquals(2, serviceNode.getChildren().size());
+
+		// remove chart from label_size_chart
+		ws.removeSelectedService("validation.label_size_chart", CHART_VISUALIZER);
+//		ws.removeServiceNode("validation.label_size_chart.chart_visualizer");
+
+		assertEquals(1, serviceNode.getChildren().size());
 	}
 }