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diff --git a/bundles/org.simantics.utils.datastructures/src/org/simantics/utils/datastructures/disposable/AbstractDisposable.java b/bundles/org.simantics.utils.datastructures/src/org/simantics/utils/datastructures/disposable/AbstractDisposable.java
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index 000000000..745e8f0a7
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+/*******************************************************************************
+ * Copyright (c) 2007, 2010 Association for Decentralized Information Management
+ * in Industry THTH ry.
+ * 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:
+ *     VTT Technical Research Centre of Finland - initial API and implementation
+ *******************************************************************************/
+
+/*
+ *
+ * @author Toni Kalajainen
+ */
+package org.simantics.utils.datastructures.disposable;
+
+import java.lang.reflect.Method;
+
+import org.simantics.utils.threads.IThreadWorkQueue;
+import org.simantics.utils.threads.SyncListenerList;
+
+/**
+ * Base implementation of IDisposable. The subclass must implement doDispose()
+ * method. It invoked at once in first dispose call. Subsequent calls to dispose
+ * throws an AssertionError.
+ * <p>
+ * assertNotDisposed() ensures that the object has not beed disposed. If so,
+ * AssertionError is thrown. assertNotDisposed() should be installed in all
+ * public methods of subclass.
+ * <p>
+ * Object is disposed in finalize, if dispose has not been invoked explicitely.
+ */
+public abstract class AbstractDisposable implements IDisposable {
+
+    SyncListenerList<IDisposeListener> disposeListeners = null;
+
+    private DisposeState disposeStatus = DisposeState.Alive;
+
+    protected void assertNotDisposed() {
+        if (isDisposed())
+            throw new AssertionError(this + " is disposed.");
+    }
+
+    @Override
+    public DisposeState getDisposeState() {
+        return disposeStatus;
+    }
+    
+    public boolean isDisposed() {
+        return disposeStatus == DisposeState.Disposed;
+    }
+    
+    public boolean isAlive() {
+        return disposeStatus == DisposeState.Alive;
+    }
+    
+    @Override
+    public void dispose() {
+        try {
+            synchronized (this) {
+                if (disposeStatus == DisposeState.Disposing)
+                    return;
+                assertNotDisposed();
+                disposeStatus = DisposeState.Disposing;
+            }
+            try {
+                fireDisposed();
+            } finally {
+                doDispose();
+            }
+        } finally {
+            synchronized(this) {
+                disposeStatus = DisposeState.Disposed;
+            }
+        }
+    }
+    
+    /**
+     * Disposes if not disposed
+     */
+    public void safeDispose() {        
+        try {
+            synchronized (this) {
+                if (disposeStatus != DisposeState.Alive)
+                    return;
+                disposeStatus = DisposeState.Disposing;
+            }
+            try {
+                fireDisposed();
+            } finally {
+                doDispose();
+            }
+        } finally {
+            synchronized(this) {
+                disposeStatus = DisposeState.Disposed;
+            }
+        }
+    }
+
+    /**
+     * Do dispose procedures. This method is invoked at most once.
+     */
+    protected abstract void doDispose();
+
+    protected boolean hasDisposeListeners() {
+        return disposeListeners!=null && !disposeListeners.isEmpty();
+    }
+
+    private final static Method onDisposed = SyncListenerList.getMethod(IDisposeListener.class, "onDisposed");
+
+    private void fireDisposed() {
+        if (disposeListeners==null) return;
+        disposeListeners.fireEventSync(onDisposed, this);
+    }
+
+    @SuppressWarnings("unused")
+    private void fireDisposedAsync() {
+        if (disposeListeners==null) return;
+        disposeListeners.fireEventAsync(onDisposed, this);
+    }
+
+    @Override
+    public void addDisposeListener(IDisposeListener listener) {
+        lazyGetListenerList().add(listener);
+    }
+
+    @Override
+    public void addDisposeListener(IDisposeListener listener, IThreadWorkQueue thread) {
+        lazyGetListenerList().add(thread, listener);
+    }
+
+    @Override
+    public void removeDisposeListener(IDisposeListener listener) {
+        if (disposeListeners==null) return;
+        disposeListeners.remove(listener);
+    }
+
+    @Override
+    public void removeDisposeListener(IDisposeListener listener, IThreadWorkQueue thread) {
+        if (disposeListeners==null) return;
+        disposeListeners.remove(thread, listener);
+    }
+    
+    private synchronized SyncListenerList<IDisposeListener> lazyGetListenerList()
+    {
+        if (disposeListeners==null)
+            disposeListeners = new SyncListenerList<IDisposeListener>(IDisposeListener.class);
+        return disposeListeners;
+    }
+    
+    /*
+    @Override
+    protected void finalize() throws Throwable {
+        try {
+            safeDispose();
+        } finally {
+            super.finalize();
+        }
+    }
+    */
+    
+}