1 files changed, 128 insertions, 0 deletions
diff --git a/extraplugins/migration/org.eclipse.papyrus.migration.common/src/org/eclipse/papyrus/migration/common/internal/Scheduler.java b/extraplugins/migration/org.eclipse.papyrus.migration.common/src/org/eclipse/papyrus/migration/common/internal/Scheduler.java
new file mode 100644
index 00000000000..4dc21d8e92f
--- /dev/null
+++ b/extraplugins/migration/org.eclipse.papyrus.migration.common/src/org/eclipse/papyrus/migration/common/internal/Scheduler.java
@@ -0,0 +1,128 @@
+/*****************************************************************************
+ * Copyright (c) 2014 CEA LIST.
+ *
+ * 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:
+ *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
+ *  Vincent Lorenzo (CEA LIST) vincent.lorenzo@cea.fr - bug 496176
+ *****************************************************************************/
+package org.eclipse.papyrus.migration.common.internal;
+
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+
+import org.eclipse.core.runtime.IProgressMonitor;
+import org.eclipse.papyrus.migration.common.Activator;
+
+
+/**
+ * Executes a number of parallel tasks on the specified (maximum) amount of threads
+ *
+ * @author Camille Letavernier
+ *
+ */
+public class Scheduler {
+
+	protected int maxThreads;
+
+	public Scheduler(int maxThreads) {
+		this.maxThreads = Math.max(1, maxThreads);
+	}
+
+	public void schedule(IProgressMonitor monitor, List<? extends Schedulable> tasks) {
+
+		List<Schedulable> remainingTasks = new LinkedList<Schedulable>(tasks);
+		List<Schedulable> runningTasks = new LinkedList<Schedulable>();
+
+		while (!remainingTasks.isEmpty()) {
+			if (monitor.isCanceled()) {
+				monitor.subTask("Canceling remaining jobs...");
+				for (Schedulable task : runningTasks) {
+					task.cancel();
+				}
+				remainingTasks.clear(); // Don't start these transformations at all
+				// Keep waiting: the cancel operation is asynchronous, we still need to wait for the jobs to complete
+			}
+
+			// Schedule transformations if we have enough threads and they have not all been scheduled
+			while (runningTasks.size() < maxThreads && !remainingTasks.isEmpty()) {
+				final Schedulable task = remainingTasks.remove(0); // Get and remove
+				task.start();
+				runningTasks.add(task);
+			}
+
+			if (!runningTasks.isEmpty()) {
+				String waitFor = runningTasks.get(0).getName();
+				monitor.subTask("Waiting for Import " + waitFor + " to complete...");
+			}
+
+			// We can continue if at least one transformation is complete (Leaving a free Thread)
+			boolean canContinue = false;
+
+			Iterator<Schedulable> iterator = runningTasks.iterator();
+			while (iterator.hasNext()) {
+				Schedulable runningTask = iterator.next();
+				if (runningTask.isComplete()) {
+					canContinue = true;
+					iterator.remove();
+					monitor.worked(1);
+				}
+			}
+
+			if (!canContinue) {
+				try {
+					Thread.sleep(100);
+				} catch (InterruptedException ex) {
+					Activator.log.error(ex);
+				}
+			}
+		}
+
+		// All transformations have been scheduled (But not necessarily completed): wait for all of them to complete
+		wait(runningTasks, monitor);
+	}
+
+
+	// Wait for all (remaining) import transformations to complete
+	protected void wait(List<Schedulable> tasks, IProgressMonitor monitor) {
+
+		// Transformations still running
+		List<Schedulable> runningTasks = new LinkedList<Schedulable>(tasks);
+
+		while (!runningTasks.isEmpty()) {
+			if (monitor.isCanceled()) {
+				monitor.subTask("Canceling remaining jobs...");
+				for (Schedulable task : runningTasks) {
+					task.cancel();
+				}
+				// Keep waiting: the cancel operation is asynchronous, we still need to wait for the jobs to complete
+			}
+
+			Iterator<Schedulable> iterator = runningTasks.iterator();
+			while (iterator.hasNext()) {
+				Schedulable task = iterator.next();
+				if (task.isComplete()) {
+					iterator.remove();
+					monitor.worked(1);
+				}
+			}
+
+			if (!runningTasks.isEmpty()) {
+				String waitFor = runningTasks.get(0).getName();
+				monitor.subTask("Waiting for " + waitFor + " to complete...");
+
+				try {
+					Thread.sleep(100);
+				} catch (InterruptedException ex) {
+					Activator.log.error(ex);
+					return;
+				}
+			}
+		}
+	}
+}