From 6c80c45e3010bfe992b41dd8800d2c4b65e0d5ef Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Fri, 19 May 2000 17:55:34 +0000 Subject: Jumbo patch: * Imported beans and serialization * Updated IA-64 port * Miscellaneous bug fixes From-SVN: r34028 --- libjava/java/beans/PropertyChangeSupport.java | 203 ++++++++++++++++++++++++++ 1 file changed, 203 insertions(+) create mode 100644 libjava/java/beans/PropertyChangeSupport.java (limited to 'libjava/java/beans/PropertyChangeSupport.java') diff --git a/libjava/java/beans/PropertyChangeSupport.java b/libjava/java/beans/PropertyChangeSupport.java new file mode 100644 index 00000000000..512c8edeb7d --- /dev/null +++ b/libjava/java/beans/PropertyChangeSupport.java @@ -0,0 +1,203 @@ +/* java.beans.PropertyChangeSupport + Copyright (C) 1998, 1999 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 +General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA +02111-1307 USA. + +As a special exception, if you link this library with other files to +produce an executable, this library does not by itself cause the +resulting executable to be covered by the GNU General Public License. +This exception does not however invalidate any other reasons why the +executable file might be covered by the GNU General Public License. */ + + +package java.beans; +import java.util.Hashtable; +import java.util.Vector; + +/** + ** PropertyChangeSupport makes it easy to fire property + ** change events and handle listeners. + ** + ** @author John Keiser + ** @since JDK1.1 + ** @version 1.2.0, 15 Mar 1999 + **/ + +public class PropertyChangeSupport implements java.io.Serializable { + Hashtable propertyListeners = new Hashtable(); + Vector listeners = new Vector(); + Object bean; + + /** Create PropertyChangeSupport to work with a specific + ** source bean. + ** @param bean the source bean to use. + **/ + public PropertyChangeSupport(Object bean) { + this.bean = bean; + } + + /** Adds a PropertyChangeListener to the list of listeners. + ** All property change events will be sent to this listener. + **

+ ** + ** The listener add is not unique: that is, n adds with + ** the same listener will result in n events being sent + ** to that listener for every property change. + **

+ ** + ** Adding a null listener will cause undefined behavior. + ** + ** @param l the listener to add. + **/ + public void addPropertyChangeListener(PropertyChangeListener l) { + listeners.addElement(l); + } + + /** Adds a PropertyChangeListener listening on the specified property. + ** Events will be sent to the listener for that particular property. + **

+ ** + ** The listener add is not unique; that is, n adds on a + ** particular property for a particular listener will result in + ** n events being sent to that listener when that + ** property is changed. + **

+ ** + ** The effect is cumulative, too; if you are registered to listen + ** to receive events on all property changes, and then you + ** register on a particular property, you will receive change + ** events for that property twice. + **

+ ** + ** Adding a null listener will cause undefined behavior. + ** + ** @param propertyName the name of the property to listen on. + ** @param l the listener to add. + **/ + public void addPropertyChangeListener(String propertyName, PropertyChangeListener l) { + synchronized(propertyListeners) { + Vector v = (Vector)propertyListeners.get(propertyName); + try { + v.addElement(l); + } catch(NullPointerException e) { + /* If v is not found, create a new vector. */ + v = new Vector(); + v.addElement(l); + propertyListeners.put(propertyName, v); + } + } + } + + /** Removes a PropertyChangeListener from the list of listeners. + ** If any specific properties are being listened on, they must + ** be deregistered by themselves; this will only remove the + ** general listener to all properties. + **

+ ** + ** If add() has been called multiple times for a + ** particular listener, remove() will have to be + ** called the same number of times to deregister it. + ** + ** @param l the listener to remove. + **/ + public void removePropertyChangeListener(PropertyChangeListener l) { + listeners.removeElement(l); + } + + /** Removes a PropertyChangeListener from listening to a specific property. + **

+ ** + ** If add() has been called multiple times for a + ** particular listener on a property, remove() will + ** have to be called the same number of times to deregister it. + ** + ** @param propertyName the property to stop listening on. + ** @param l the listener to remove. + **/ + public void removePropertyChangeListener(String propertyName, PropertyChangeListener l) { + synchronized(propertyListeners) { + Vector v = (Vector)propertyListeners.get(propertyName); + try { + v.removeElement(l); + if(v.size() == 0) { + propertyListeners.remove(propertyName); + } + } catch(NullPointerException e) { + /* if v is not found, do nothing. */ + } + } + } + + /** Fire a PropertyChangeEvent to all the listeners. + ** + ** @param event the event to fire. + **/ + public void firePropertyChange(PropertyChangeEvent event) { + for(int i=0;itrue if there are listeners + ** on all properties or if there is a listener specifically on this + ** property. + ** + ** @param propertyName the property that may be listened on + ** @return whether the property is being listened on + **/ + public boolean hasListeners(String propertyName) { + return listeners.size() > 0 || propertyListeners.get(propertyName) != null; + } +} -- cgit v1.2.3