1 files changed, 220 insertions, 0 deletions
diff --git a/target_explorer/plugins/org.eclipse.tcf.te.runtime/src/org/eclipse/tcf/te/runtime/extensions/AbstractExtensionPointManager.java b/target_explorer/plugins/org.eclipse.tcf.te.runtime/src/org/eclipse/tcf/te/runtime/extensions/AbstractExtensionPointManager.java
new file mode 100644
index 000000000..336f3b0c5
--- /dev/null
+++ b/target_explorer/plugins/org.eclipse.tcf.te.runtime/src/org/eclipse/tcf/te/runtime/extensions/AbstractExtensionPointManager.java
@@ -0,0 +1,220 @@
+/*******************************************************************************
+ * Copyright (c) 2011 Wind River Systems, Inc. and others. All rights reserved.
+ * This program and the accompanying materials are made available under the terms
+ * of the Eclipse Public License v1.0 which accompanies this distribution, and is
+ * available at http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ * Wind River Systems - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.tcf.te.runtime.extensions;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.eclipse.core.runtime.Assert;
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.IConfigurationElement;
+import org.eclipse.core.runtime.IExtension;
+import org.eclipse.core.runtime.IExtensionPoint;
+import org.eclipse.core.runtime.IExtensionRegistry;
+import org.eclipse.core.runtime.IStatus;
+import org.eclipse.core.runtime.Platform;
+import org.eclipse.core.runtime.Status;
+import org.eclipse.osgi.util.NLS;
+import org.eclipse.tcf.te.runtime.activator.CoreBundleActivator;
+import org.eclipse.tcf.te.runtime.nls.Messages;
+
+/**
+ * Abstract extension point manager implementation.
+ */
+public abstract class AbstractExtensionPointManager<V> {
+	// Flag to mark the extension point manager initialized (extensions loaded).
+	private boolean initialized = false;
+	// The map of loaded extension listed by their unique id's
+	private Map<String, ExecutableExtensionProxy<V>> extensionsMap = new LinkedHashMap<String, ExecutableExtensionProxy<V>>();
+	// The extension point comparator
+	private ExtensionPointComparator comparator = null;
+
+	/**
+	 * Constructor.
+	 */
+	public AbstractExtensionPointManager() {
+	}
+
+	/**
+	 * Returns if or if not the extension point manager got initialized already.
+	 * <p>
+	 * Initialized means that the manager read the extensions for the managed extension point.
+	 *
+	 * @return <code>True</code> if already initialized, <code>false</code> otherwise.
+	 */
+	protected boolean isInitialized() {
+		return initialized;
+	}
+
+	/**
+	 * Sets if or if not the extension point manager is initialized.
+	 * <p>
+	 * Initialized means that the manager has read the extensions for the managed extension point.
+	 *
+	 * @return <code>True</code> to set the extension point manager is initialized, <code>false</code> otherwise.
+	 */
+	protected void setInitialized(boolean initialized) {
+		this.initialized = initialized;
+	}
+
+	/**
+	 * Returns the map of managed extensions. If not loaded before,
+	 * this methods trigger the loading of the extensions to the managed
+	 * extension point.
+	 *
+	 * @return The map of extensions.
+	 */
+	protected Map<String, ExecutableExtensionProxy<V>> getExtensions() {
+		// Load and store the extensions thread-safe!
+		synchronized (extensionsMap) {
+			if (!isInitialized()) { loadExtensions(); setInitialized(true); }
+		}
+		return extensionsMap;
+	}
+
+	/**
+	 * Returns the extensions of the specified extension point sorted.
+	 * <p>
+	 * For the order of the extensions, see {@link ExtensionPointComparator}.
+	 *
+	 * @param point The extension point. Must be not <code>null</code>.
+	 * @return The extensions in sorted order or an empty array if the extension point has no extensions.
+	 */
+	protected IExtension[] getExtensionsSorted(IExtensionPoint point) {
+		assert point != null;
+
+		List<IExtension> extensions = new ArrayList<IExtension>(Arrays.asList(point.getExtensions()));
+		if (extensions.size() > 0) {
+			Collections.sort(extensions, getExtensionPointComparator());
+		}
+
+		return extensions.toArray(new IExtension[extensions.size()]);
+	}
+
+	/**
+	 * Returns the extension point comparator instance. If not available,
+	 * {@link #doCreateExtensionPointComparator()} is called to create a new instance.
+	 *
+	 * @return The extension point comparator or <code>null</code> if the instance creation fails.
+	 */
+	protected final ExtensionPointComparator getExtensionPointComparator() {
+		if (comparator == null) {
+			comparator = doCreateExtensionPointComparator();
+		}
+		return comparator;
+	}
+
+	/**
+	 * Creates a new extension point comparator instance.
+	 *
+	 * @return The extension point comparator instance.
+	 */
+	protected ExtensionPointComparator doCreateExtensionPointComparator() {
+		return new ExtensionPointComparator();
+	}
+
+	/**
+	 * Returns the extension point id to read. The method
+	 * must return never <code>null</code>.
+	 *
+	 * @return The extension point id.
+	 */
+	protected abstract String getExtensionPointId();
+
+	/**
+	 * Returns the configuration element name. The method
+	 * must return never <code>null</code>.
+	 *
+	 * @return The configuration element name.
+	 */
+	protected abstract String getConfigurationElementName();
+
+	/**
+	 * Creates the extension proxy instance.
+	 *
+	 * @param element The configuration element of the extension. Must not be <code>null</code>.
+	 * @return The extension proxy instance.
+	 *
+	 * @throws CoreException If the extension proxy instantiation failed.
+	 */
+	protected ExecutableExtensionProxy<V> doCreateExtensionProxy(IConfigurationElement element) throws CoreException {
+		Assert.isNotNull(element);
+		return new ExecutableExtensionProxy<V>(element);
+	}
+
+	/**
+	 * Store the given extension to the given extensions store. Checks if an extension with the same id does exist
+	 * already and throws an exception in this case.
+	 *
+	 * @param extensions The extensions store. Must not be <code>null</code>.
+	 * @param candidate The extension. Must not be <code>null</code>.
+	 * @param element The configuration element. Must not be <code>null</code>.
+	 *
+	 * @throws CoreException In case a extension with the same id as the given extension already exist.
+	 */
+	protected void doStoreExtensionTo(Map<String, ExecutableExtensionProxy<V>> extensions, ExecutableExtensionProxy<V> candidate, IConfigurationElement element) throws CoreException {
+		Assert.isNotNull(extensions);
+		Assert.isNotNull(candidate);
+		Assert.isNotNull(element);
+
+		// If no extension with this id had been registered before, register now.
+		if (!extensions.containsKey(candidate.getId())) {
+			extensions.put(candidate.getId(), candidate);
+		}
+		else {
+			throw new CoreException(new Status(IStatus.ERROR,
+					CoreBundleActivator.getUniqueIdentifier(),
+					0,
+					NLS.bind(Messages.Extension_error_duplicateExtension, candidate.getId(), element.getContributor().getName()),
+					null));
+		}
+	}
+
+	/**
+	 * Loads the extensions for the managed extension point.
+	 */
+	protected void loadExtensions() {
+		// If already initialized, this method will do nothing.
+		if (isInitialized())  return;
+
+		IExtensionRegistry registry = Platform.getExtensionRegistry();
+		IExtensionPoint point = registry.getExtensionPoint(getExtensionPointId());
+		if (point != null) {
+			IExtension[] extensions = getExtensionsSorted(point);
+			for (IExtension extension : extensions) {
+				IConfigurationElement[] elements = extension.getConfigurationElements();
+				for (IConfigurationElement element : elements) {
+					if (getConfigurationElementName().equals(element.getName())) {
+						try {
+							ExecutableExtensionProxy<V> candidate = doCreateExtensionProxy(element);
+							if (candidate.getId() != null) {
+								doStoreExtensionTo(extensionsMap, candidate, element);
+							} else {
+								throw new CoreException(new Status(IStatus.ERROR,
+										CoreBundleActivator.getUniqueIdentifier(),
+										0,
+										NLS.bind(Messages.Extension_error_missingRequiredAttribute, "id", element.getAttribute("label")), //$NON-NLS-1$ //$NON-NLS-2$
+										null));
+							}
+						} catch (CoreException e) {
+							Platform.getLog(CoreBundleActivator.getContext().getBundle()).log(new Status(IStatus.ERROR,
+									CoreBundleActivator.getUniqueIdentifier(),
+									NLS.bind(Messages.Extension_error_invalidExtensionPoint, element.getDeclaringExtension().getUniqueIdentifier()), e));
+						}
+					}
+				}
+			}
+		}
+	}
+}