| /* VetoableChangeSupport.java -- support to manage vetoable change listeners |
| Copyright (C) 1998, 1999, 2000, 2002, 2005, 2006, |
| 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., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package java.beans; |
| |
| import java.io.IOException; |
| import java.io.ObjectInputStream; |
| import java.io.ObjectOutputStream; |
| import java.io.Serializable; |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Hashtable; |
| import java.util.Iterator; |
| import java.util.Map.Entry; |
| import java.util.Vector; |
| |
| /** |
| * VetoableChangeSupport makes it easy to fire vetoable change events and |
| * handle listeners. It allows chaining of listeners, as well as filtering |
| * by property name. In addition, it will serialize only those listeners |
| * which are serializable, ignoring the others without problem. This class |
| * is thread-safe. |
| * |
| * @author John Keiser |
| * @author Eric Blake (ebb9@email.byu.edu) |
| * @since 1.1 |
| * @status updated to 1.4 |
| */ |
| public class VetoableChangeSupport implements Serializable |
| { |
| /** |
| * Compatible with JDK 1.1+. |
| */ |
| private static final long serialVersionUID = -5090210921595982017L; |
| |
| /** |
| * Maps property names (String) to named listeners (VetoableChangeSupport). |
| * If this is a child instance, this field will be null. |
| * |
| * @serial the map of property names to named listener managers |
| * @since 1.2 |
| */ |
| private Hashtable children; |
| |
| /** |
| * The non-null source object for any generated events. |
| * |
| * @serial the event source |
| */ |
| private final Object source; |
| |
| /** |
| * A field to compare serialization versions - this class uses version 2. |
| * |
| * @serial the serialization format |
| */ |
| private static final int vetoableChangeSupportSerializedDataVersion = 2; |
| |
| /** |
| * The list of all registered vetoable listeners. If this instance was |
| * created by user code, this only holds the global listeners (ie. not tied |
| * to a name), and may be null. If it was created by this class, as a |
| * helper for named properties, then this vector will be non-null, and this |
| * instance appears as a value in the <code>children</code> hashtable of |
| * another instance, so that the listeners are tied to the key of that |
| * hashtable entry. |
| */ |
| private transient Vector listeners; |
| |
| /** |
| * Create a VetoableChangeSupport to work with a specific source bean. |
| * |
| * @param source the source bean to use |
| * @throws NullPointerException if source is null |
| */ |
| public VetoableChangeSupport(Object source) |
| { |
| this.source = source; |
| if (source == null) |
| throw new NullPointerException(); |
| } |
| |
| /** |
| * Adds a VetoableChangeListener to the list of global listeners. All |
| * vetoable change events will be sent to this listener. The listener add |
| * is not unique: that is, <em>n</em> adds with the same listener will |
| * result in <em>n</em> events being sent to that listener for every |
| * vetoable change. This method will unwrap a VetoableChangeListenerProxy, |
| * registering the underlying delegate to the named property list. |
| * |
| * @param l the listener to add (<code>null</code> ignored). |
| */ |
| public synchronized void addVetoableChangeListener(VetoableChangeListener l) |
| { |
| if (l == null) |
| return; |
| if (l instanceof VetoableChangeListenerProxy) |
| { |
| VetoableChangeListenerProxy p = (VetoableChangeListenerProxy) l; |
| addVetoableChangeListener(p.propertyName, |
| (VetoableChangeListener) p.getListener()); |
| } |
| else |
| { |
| if (listeners == null) |
| listeners = new Vector(); |
| listeners.add(l); |
| } |
| } |
| |
| /** |
| * Removes a VetoableChangeListener from the list of global 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 <code>add()</code> has been called multiple times for a |
| * particular listener, <code>remove()</code> will have to be called the |
| * same number of times to deregister it. This method will unwrap a |
| * VetoableChangeListenerProxy, removing the underlying delegate from the |
| * named property list. |
| * |
| * @param l the listener to remove |
| */ |
| public synchronized void |
| removeVetoableChangeListener(VetoableChangeListener l) |
| { |
| if (l instanceof VetoableChangeListenerProxy) |
| { |
| VetoableChangeListenerProxy p = (VetoableChangeListenerProxy) l; |
| removeVetoableChangeListener(p.propertyName, |
| (VetoableChangeListener) p.getListener()); |
| } |
| else if (listeners != null) |
| { |
| listeners.remove(l); |
| if (listeners.isEmpty()) |
| listeners = null; |
| } |
| } |
| |
| /** |
| * Returns an array of all registered vetoable change listeners. Those that |
| * were registered under a name will be wrapped in a |
| * <code>VetoableChangeListenerProxy</code>, so you must check whether the |
| * listener is an instance of the proxy class in order to see what name the |
| * real listener is registered under. If there are no registered listeners, |
| * this returns an empty array. |
| * |
| * @return the array of registered listeners |
| * @see VetoableChangeListenerProxy |
| * @since 1.4 |
| */ |
| public synchronized VetoableChangeListener[] getVetoableChangeListeners() |
| { |
| ArrayList list = new ArrayList(); |
| if (listeners != null) |
| list.addAll(listeners); |
| if (children != null) |
| { |
| int i = children.size(); |
| Iterator iter = children.entrySet().iterator(); |
| while (--i >= 0) |
| { |
| Entry e = (Entry) iter.next(); |
| String name = (String) e.getKey(); |
| Vector v = ((VetoableChangeSupport) e.getValue()).listeners; |
| int j = v.size(); |
| while (--j >= 0) |
| list.add(new VetoableChangeListenerProxy |
| (name, (VetoableChangeListener) v.get(j))); |
| } |
| } |
| return (VetoableChangeListener[]) |
| list.toArray(new VetoableChangeListener[list.size()]); |
| } |
| |
| /** |
| * Adds a VetoableChangeListener listening on the specified property. Events |
| * will be sent to the listener only if the property name matches. The |
| * listener add is not unique; that is, <em>n</em> adds on a particular |
| * property for a particular listener will result in <em>n</em> 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 vetoable changes, and then you register on a particular property, |
| * you will receive change events for that property twice. This method |
| * will unwrap a VetoableChangeListenerProxy, registering the underlying |
| * delegate to the named property list if the names match, and discarding |
| * it otherwise. |
| * |
| * @param propertyName the name of the property to listen on |
| * @param l the listener to add |
| */ |
| public synchronized void addVetoableChangeListener(String propertyName, |
| VetoableChangeListener l) |
| { |
| if (propertyName == null || l == null) |
| return; |
| while (l instanceof VetoableChangeListenerProxy) |
| { |
| VetoableChangeListenerProxy p = (VetoableChangeListenerProxy) l; |
| if (propertyName == null ? p.propertyName != null |
| : ! propertyName.equals(p.propertyName)) |
| return; |
| l = (VetoableChangeListener) p.getListener(); |
| } |
| VetoableChangeSupport s = null; |
| if (children == null) |
| children = new Hashtable(); |
| else |
| s = (VetoableChangeSupport) children.get(propertyName); |
| if (s == null) |
| { |
| s = new VetoableChangeSupport(source); |
| s.listeners = new Vector(); |
| children.put(propertyName, s); |
| } |
| s.listeners.add(l); |
| } |
| |
| /** |
| * Removes a VetoableChangeListener from listening to a specific property. |
| * If <code>add()</code> has been called multiple times for a particular |
| * listener on a property, <code>remove()</code> will have to be called the |
| * same number of times to deregister it. This method will unwrap a |
| * VetoableChangeListenerProxy, removing the underlying delegate from the |
| * named property list if the names match. |
| * |
| * @param propertyName the property to stop listening on |
| * @param l the listener to remove |
| * @throws NullPointerException if propertyName is null |
| */ |
| public synchronized void |
| removeVetoableChangeListener(String propertyName, VetoableChangeListener l) |
| { |
| if (children == null) |
| return; |
| VetoableChangeSupport s |
| = (VetoableChangeSupport) children.get(propertyName); |
| if (s == null) |
| return; |
| while (l instanceof VetoableChangeListenerProxy) |
| { |
| VetoableChangeListenerProxy p = (VetoableChangeListenerProxy) l; |
| if (propertyName == null ? p.propertyName != null |
| : ! propertyName.equals(p.propertyName)) |
| return; |
| l = (VetoableChangeListener) p.getListener(); |
| } |
| s.listeners.remove(l); |
| if (s.listeners.isEmpty()) |
| { |
| children.remove(propertyName); |
| if (children.isEmpty()) |
| children = null; |
| } |
| } |
| |
| /** |
| * Returns an array of all vetoable change listeners registered under the |
| * given property name. If there are no registered listeners, this returns |
| * an empty array. |
| * |
| * @return the array of registered listeners |
| * @throws NullPointerException if propertyName is null |
| * @since 1.4 |
| */ |
| public synchronized VetoableChangeListener[] |
| getVetoableChangeListeners(String propertyName) |
| { |
| if (children == null) |
| return new VetoableChangeListener[0]; |
| VetoableChangeSupport s |
| = (VetoableChangeSupport) children.get(propertyName); |
| if (s == null) |
| return new VetoableChangeListener[0]; |
| return (VetoableChangeListener[]) |
| s.listeners.toArray(new VetoableChangeListener[s.listeners.size()]); |
| } |
| |
| /** |
| * Fire a PropertyChangeEvent containing the old and new values of the |
| * property to all the global listeners, and to all the listeners for the |
| * specified property name. This does nothing if old and new are non-null |
| * and equal. If the change is vetoed, a new event is fired to notify |
| * listeners about the rollback before the exception is thrown. |
| * |
| * @param propertyName the name of the property that changed |
| * @param oldVal the old value |
| * @param newVal the new value |
| * @throws PropertyVetoException if the change is vetoed by a listener |
| */ |
| public void fireVetoableChange(String propertyName, |
| Object oldVal, Object newVal) |
| throws PropertyVetoException |
| { |
| fireVetoableChange(new PropertyChangeEvent(source, propertyName, |
| oldVal, newVal)); |
| } |
| |
| /** |
| * Fire a PropertyChangeEvent containing the old and new values of the |
| * property to all the global listeners, and to all the listeners for the |
| * specified property name. This does nothing if old and new are equal. |
| * If the change is vetoed, a new event is fired to notify listeners about |
| * the rollback before the exception is thrown. |
| * |
| * @param propertyName the name of the property that changed |
| * @param oldVal the old value |
| * @param newVal the new value |
| * @throws PropertyVetoException if the change is vetoed by a listener |
| */ |
| public void fireVetoableChange(String propertyName, int oldVal, int newVal) |
| throws PropertyVetoException |
| { |
| if (oldVal != newVal) |
| fireVetoableChange(new PropertyChangeEvent(source, propertyName, |
| new Integer(oldVal), |
| new Integer(newVal))); |
| } |
| |
| /** |
| * Fire a PropertyChangeEvent containing the old and new values of the |
| * property to all the global listeners, and to all the listeners for the |
| * specified property name. This does nothing if old and new are equal. |
| * If the change is vetoed, a new event is fired to notify listeners about |
| * the rollback before the exception is thrown. |
| * |
| * @param propertyName the name of the property that changed |
| * @param oldVal the old value |
| * @param newVal the new value |
| * @throws PropertyVetoException if the change is vetoed by a listener |
| */ |
| public void fireVetoableChange(String propertyName, |
| boolean oldVal, boolean newVal) |
| throws PropertyVetoException |
| { |
| if (oldVal != newVal) |
| fireVetoableChange(new PropertyChangeEvent(source, propertyName, |
| Boolean.valueOf(oldVal), |
| Boolean.valueOf(newVal))); |
| } |
| |
| /** |
| * Fire a PropertyChangeEvent to all the global listeners, and to all the |
| * listeners for the specified property name. This does nothing if old and |
| * new values of the event are equal. If the change is vetoed, a new event |
| * is fired to notify listeners about the rollback before the exception is |
| * thrown. |
| * |
| * @param event the event to fire |
| * @throws NullPointerException if event is null |
| * @throws PropertyVetoException if the change is vetoed by a listener |
| */ |
| public void fireVetoableChange(PropertyChangeEvent event) |
| throws PropertyVetoException |
| { |
| if (event.oldValue != null && event.oldValue.equals(event.newValue)) |
| return; |
| Vector v = listeners; // Be thread-safe. |
| if (v != null) |
| { |
| int i = v.size(); |
| try |
| { |
| while (--i >= 0) |
| ((VetoableChangeListener) v.get(i)).vetoableChange(event); |
| } |
| catch (PropertyVetoException e) |
| { |
| event = event.rollback(); |
| int limit = i; |
| i = v.size(); |
| while (--i >= limit) |
| ((VetoableChangeListener) v.get(i)).vetoableChange(event); |
| throw e; |
| } |
| } |
| Hashtable h = children; // Be thread-safe. |
| if (h != null && event.propertyName != null) |
| { |
| VetoableChangeSupport s |
| = (VetoableChangeSupport) h.get(event.propertyName); |
| if (s != null) |
| { |
| Vector v1 = s.listeners; // Be thread-safe. |
| int i = v1 == null ? 0 : v1.size(); |
| try |
| { |
| while (--i >= 0) |
| ((VetoableChangeListener) v1.get(i)).vetoableChange(event); |
| } |
| catch (PropertyVetoException e) |
| { |
| event = event.rollback(); |
| int limit = i; |
| i = v.size(); |
| while (--i >= 0) |
| ((VetoableChangeListener) v.get(i)).vetoableChange(event); |
| i = v1.size(); |
| while (--i >= limit) |
| ((VetoableChangeListener) v1.get(i)).vetoableChange(event); |
| throw e; |
| } |
| } |
| } |
| } |
| |
| /** |
| * Tell whether the specified property is being listened on or not. This |
| * will only return <code>true</code> 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 |
| * @throws NullPointerException if propertyName is null |
| */ |
| public synchronized boolean hasListeners(String propertyName) |
| { |
| return listeners != null || (children != null |
| && children.get(propertyName) != null); |
| } |
| |
| /** |
| * Saves the state of the object to the stream. |
| * |
| * @param s the stream to write to |
| * @throws IOException if anything goes wrong |
| * @serialData this writes out a null-terminated list of serializable |
| * global vetoable change listeners (the listeners for a named |
| * property are written out as the global listeners of the |
| * children, when the children hashtable is saved) |
| */ |
| private synchronized void writeObject(ObjectOutputStream s) |
| throws IOException |
| { |
| s.defaultWriteObject(); |
| if (listeners != null) |
| { |
| int i = listeners.size(); |
| while (--i >= 0) |
| if (listeners.get(i) instanceof Serializable) |
| s.writeObject(listeners.get(i)); |
| } |
| s.writeObject(null); |
| } |
| |
| /** |
| * Reads the object back from stream (deserialization). |
| * |
| * XXX Since serialization for 1.1 streams was not documented, this may |
| * not work if vetoableChangeSupportSerializedDataVersion is 1. |
| * |
| * @param s the stream to read from |
| * @throws IOException if reading the stream fails |
| * @throws ClassNotFoundException if deserialization fails |
| * @serialData this reads in a null-terminated list of serializable |
| * global vetoable change listeners (the listeners for a named |
| * property are written out as the global listeners of the |
| * children, when the children hashtable is saved) |
| */ |
| private void readObject(ObjectInputStream s) |
| throws IOException, ClassNotFoundException |
| { |
| s.defaultReadObject(); |
| VetoableChangeListener l = (VetoableChangeListener) s.readObject(); |
| while (l != null) |
| { |
| addVetoableChangeListener(l); |
| l = (VetoableChangeListener) s.readObject(); |
| } |
| // Sun is not as careful with children as we are, and lets some proxys |
| // in that can never receive events. So, we clean up anything that got |
| // serialized, to make sure our invariants hold. |
| if (children != null) |
| { |
| int i = children.size(); |
| Iterator iter = children.entrySet().iterator(); |
| while (--i >= 0) |
| { |
| Entry e = (Entry) iter.next(); |
| String name = (String) e.getKey(); |
| VetoableChangeSupport vcs = (VetoableChangeSupport) e.getValue(); |
| if (vcs.listeners == null) |
| vcs.listeners = new Vector(); |
| if (vcs.children != null) |
| vcs.listeners.addAll |
| (Arrays.asList(vcs.getVetoableChangeListeners(name))); |
| if (vcs.listeners.size() == 0) |
| iter.remove(); |
| else |
| vcs.children = null; |
| } |
| if (children.size() == 0) |
| children = null; |
| } |
| } |
| } // class VetoableChangeSupport |