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/*************************************************************************
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* Copyright 2008 by Sun Microsystems, Inc.
*
* OpenOffice.org - a multi-platform office productivity suite
*
* $RCSfile: WeakComponentBase.cs,v $
* $Revision: 1.5 $
*
* This file is part of OpenOffice.org.
*
* OpenOffice.org is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License version 3
* only, as published by the Free Software Foundation.
*
* OpenOffice.org is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License version 3 for more details
* (a copy is included in the LICENSE file that accompanied this code).
*
* You should have received a copy of the GNU Lesser General Public License
* version 3 along with OpenOffice.org. If not, see
* <http://www.openoffice.org/license.html>
* for a copy of the LGPLv3 License.
*
************************************************************************/
using System;
using unoidl.com.sun.star.lang;
namespace uno.util
{
/** This class can be used as a base class for UNO objects.
It implements the capability to be kept weakly
(unoidl.com.sun.star.uno.XWeak) and it implements
unoidl.com.sun.star.lang.XTypeProvider which is necessary for
using the object from StarBasic.
In addition, it implements the interface
unoidl.com.sun.star.lang.XComponent to be disposed explicitly.
*/
public class WeakComponentBase : WeakBase, XComponent
{
private delegate void t_disposing( EventObject evt );
private t_disposing m_disposing = null;
private bool m_inDispose = false;
private bool m_disposed = false;
/** Indicates whether object is alrady disposed.
@return
true, if object has been disposed
*/
protected bool isDisposed()
{
lock (this)
{
return m_disposed;
}
}
/** Checks whether this object is disposed and throws a DisposedException
if it is already disposed.
*/
protected void checkUnDisposed()
{
if (! isDisposed())
{
throw new unoidl.com.sun.star.lang.DisposedException(
"object already disposed!", this );
}
}
~WeakComponentBase()
{
bool doDispose;
lock (this)
{
doDispose = (!m_inDispose && !m_disposed);
}
if (doDispose)
{
dispose();
}
}
/** 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()
{
}
// XComponent impl
/** This method is called by the owner of this object to explicitly
dispose it. This implementation of dispose() first notifies this object
via preDisposing(), then all registered event listeners and
finally this object again calling postDisposing().
*/
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.
bool doDispose = false;
t_disposing call = null;
lock (this)
{
if (! m_inDispose && !m_disposed)
{
call = m_disposing;
m_disposing = null;
m_inDispose = true;
doDispose = true;
}
}
// The notification occures 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 (doDispose)
{
try
{
// call sub class
preDisposing();
// send disposing notifications to listeners
if (null != call)
{
EventObject evt = new EventObject( this );
call( evt );
}
// call sub class
postDisposing();
}
finally
{
// finally makes sure that the flags are set ensuring
// that this function is only called once.
m_disposed = true;
m_inDispose = 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
Console.WriteLine(
"WeakComponentBase.dispose() - dispose called twice" );
#endif
// Debug.Fail( "WeakComponentBase.dispose() - dispose called twice" );
}
}
/** Registers an event listener being notified when this object is disposed.
@param xListener event listener
*/
public void addEventListener( XEventListener xListener )
{
bool add;
lock (this)
{
add = (! m_inDispose && !m_disposed);
if (add)
m_disposing += new t_disposing( xListener.disposing );
}
if (! add)
xListener.disposing( new EventObject( this ) );
}
/** Revokes an event listener from being notified when this object
is disposed.
@param xListener event listener
*/
public void removeEventListener( XEventListener xListener )
{
lock (this)
{
if (! m_inDispose && !m_disposed)
m_disposing -= new t_disposing( xListener.disposing );
}
}
}
}
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