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/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* This file incorporates work covered by the following license notice:
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.apache.org/licenses/LICENSE-2.0 .
*/
package com.sun.star.lib.uno.helper;
import com.sun.star.lang.XComponent;
import com.sun.star.lang.XEventListener;
import com.sun.star.lang.EventObject;
import com.sun.star.uno.Type;
/** This class can be used as the base class for UNO components. In addition to the functionality ,which
* is inherited from WeakBase, it implements com.sun.star.lang.XComponent.
*/
public class ComponentBase extends WeakBase implements XComponent
{
private final boolean DEBUG= false;
protected MultiTypeInterfaceContainer listenerContainer;
protected boolean bInDispose= false;
protected boolean bDisposed= false;
static final Type EVT_LISTENER_TYPE= new Type(XEventListener.class);
/** Creates a new instance of CompBase */
public ComponentBase()
{
super();
listenerContainer= new MultiTypeInterfaceContainer();
}
/** Override to perform extra clean-up work. Provided for subclasses. It is
called during dispose()
*/
protected void preDisposing()
{
}
/** Override to become notified right before the disposing action is performed.
*/
protected void postDisposing()
{
}
/** Method of XComponent. It is called by the owning client when the component is not needed
* anymore. The registered listeners are notified that this method has been called.
*/
public void dispose()
{
// Determine in a thread-safe way if this is the first call to this method.
// Only then we proceed with the notification of event listeners.
// It is an error to call this method more then once.
boolean bDoDispose= false;
synchronized (this)
{
if ( ! bInDispose && ! bDisposed)
{
bDoDispose= true;
bInDispose= true;
}
}
// The notification occurs in an unsynchronized block in order to avoid
// deadlocks if one of the listeners calls back in a different thread on
// a synchronized method which uses the same object.
if (bDoDispose)
{
try
{
preDisposing();
listenerContainer.disposeAndClear(new EventObject(this));
//notify subclasses that disposing is in progress
postDisposing();
}
finally
{
// finally makes sure that the flags are set even if a RuntimeException is thrown.
// That ensures that this function is only called once.
bDisposed= true;
bInDispose= false;
}
}
else
{
// in a multithreaded environment, it can't be avoided, that dispose is called twice.
// However this condition is traced, because it MAY indicate an error.
if (DEBUG)
System.out.println("OComponentHelper::dispose() - dispose called twice" );
}
}
/** Method of XComponent.
*/
public void removeEventListener(XEventListener xEventListener)
{
listenerContainer.removeInterface( EVT_LISTENER_TYPE, xEventListener);
}
public void addEventListener(XEventListener listener)
{
boolean bDoDispose= false;
synchronized (this)
{
if (bDisposed || bInDispose)
bDoDispose= true;
else
listenerContainer.addInterface(EVT_LISTENER_TYPE, listener);
}
if (bDoDispose )
{
listener.disposing( new EventObject(this));
}
}
protected void finalize() throws Throwable
{
if ( ! bInDispose && ! bDisposed)
dispose();
super.finalize();
}
}
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