/*
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
* Foundation.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* or from the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* This program 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 for more details.
*
* Copyright (c) 2001 - 2009 Object Refinery Ltd, Pentaho Corporation and Contributors.. All rights reserved.
*/
package org.pentaho.reporting.engine.classic.core.style;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
/**
* A utility class for managing a collection of {@link StyleChangeListener} objects.
*
* @author Thomas Morgner.
*/
public class StyleChangeSupport
{
/**
* Storage for the listeners.
*/
private ArrayList listeners;
/**
* The source.
*/
private final ElementStyleSheet source;
/**
* Creates a new support object.
*
* @param source the source of change events.
*/
public StyleChangeSupport(final ElementStyleSheet source)
{
this.source = source;
}
/**
* Adds a listener.
*
* @param l the listener.
*/
public void addListener(final StyleChangeListener l)
{
if (l == null)
{
throw new NullPointerException("Listener == null");
}
if (listeners == null)
{
listeners = new ArrayList(5);
}
listeners.add(new WeakReference(l));
}
/**
* Removes a listener.
*
* @param l the listener.
*/
public void removeListener(final StyleChangeListener l)
{
if (l == null)
{
throw new NullPointerException("Listener == null");
}
if (listeners == null)
{
return;
}
listeners.remove(l);
}
/**
* Notifies all listeners that a style has changed.
*
* @param key the style key.
* @param value the new style value.
*/
public void fireStyleChanged(final StyleKey key, final Object value)
{
if (listeners == null)
{
return;
}
ArrayList removeList = null;
for (int i = 0; i < listeners.size(); i++)
{
final WeakReference ref = (WeakReference) listeners.get(i);
final StyleChangeListener l = (StyleChangeListener) ref.get();
if (l != null)
{
l.styleChanged(source, key, value);
}
else
{
if (removeList == null)
{
removeList = new ArrayList(5);
}
removeList.add(ref);
}
}
if (removeList != null)
{
listeners.removeAll(removeList);
}
}
/**
* Notifies all listeners that a style has been removed.
*
* @param key the style key.
*/
public void fireStyleRemoved(final StyleKey key)
{
if (listeners == null)
{
return;
}
ArrayList removeList = null;
for (int i = 0; i < listeners.size(); i++)
{
final WeakReference ref = (WeakReference) listeners.get(i);
final StyleChangeListener l = (StyleChangeListener) ref.get();
if (l != null)
{
l.styleRemoved(source, key);
}
else
{
if (removeList == null)
{
removeList = new ArrayList(5);
}
removeList.add(ref);
}
}
if (removeList != null)
{
listeners.removeAll(removeList);
}
}
}