jdk/src/java.desktop/share/classes/java/beans/PropertyChangeSupport.java
changeset 25859 3317bb8137f4
parent 25130 adfaa02ea516
child 26037 508779ce6619
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/java.desktop/share/classes/java/beans/PropertyChangeSupport.java	Sun Aug 17 15:54:13 2014 +0100
@@ -0,0 +1,554 @@
+/*
+ * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code 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
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package java.beans;
+
+import java.io.Serializable;
+import java.io.ObjectStreamField;
+import java.io.ObjectOutputStream;
+import java.io.ObjectInputStream;
+import java.io.IOException;
+import java.util.Hashtable;
+import java.util.Map.Entry;
+
+/**
+ * This is a utility class that can be used by beans that support bound
+ * properties.  It manages a list of listeners and dispatches
+ * {@link PropertyChangeEvent}s to them.  You can use an instance of this class
+ * as a member field of your bean and delegate these types of work to it.
+ * The {@link PropertyChangeListener} can be registered for all properties
+ * or for a property specified by name.
+ * <p>
+ * Here is an example of {@code PropertyChangeSupport} usage that follows
+ * the rules and recommendations laid out in the JavaBeans&trade; specification:
+ * <pre>
+ * public class MyBean {
+ *     private final PropertyChangeSupport pcs = new PropertyChangeSupport(this);
+ *
+ *     public void addPropertyChangeListener(PropertyChangeListener listener) {
+ *         this.pcs.addPropertyChangeListener(listener);
+ *     }
+ *
+ *     public void removePropertyChangeListener(PropertyChangeListener listener) {
+ *         this.pcs.removePropertyChangeListener(listener);
+ *     }
+ *
+ *     private String value;
+ *
+ *     public String getValue() {
+ *         return this.value;
+ *     }
+ *
+ *     public void setValue(String newValue) {
+ *         String oldValue = this.value;
+ *         this.value = newValue;
+ *         this.pcs.firePropertyChange("value", oldValue, newValue);
+ *     }
+ *
+ *     [...]
+ * }
+ * </pre>
+ * <p>
+ * A {@code PropertyChangeSupport} instance is thread-safe.
+ * <p>
+ * This class is serializable.  When it is serialized it will save
+ * (and restore) any listeners that are themselves serializable.  Any
+ * non-serializable listeners will be skipped during serialization.
+ *
+ * @see VetoableChangeSupport
+ * @since 1.1
+ */
+public class PropertyChangeSupport implements Serializable {
+    private PropertyChangeListenerMap map = new PropertyChangeListenerMap();
+
+    /**
+     * Constructs a <code>PropertyChangeSupport</code> object.
+     *
+     * @param sourceBean  The bean to be given as the source for any events.
+     */
+    public PropertyChangeSupport(Object sourceBean) {
+        if (sourceBean == null) {
+            throw new NullPointerException();
+        }
+        source = sourceBean;
+    }
+
+    /**
+     * Add a PropertyChangeListener to the listener list.
+     * The listener is registered for all properties.
+     * The same listener object may be added more than once, and will be called
+     * as many times as it is added.
+     * If <code>listener</code> is null, no exception is thrown and no action
+     * is taken.
+     *
+     * @param listener  The PropertyChangeListener to be added
+     */
+    public void addPropertyChangeListener(PropertyChangeListener listener) {
+        if (listener == null) {
+            return;
+        }
+        if (listener instanceof PropertyChangeListenerProxy) {
+            PropertyChangeListenerProxy proxy =
+                   (PropertyChangeListenerProxy)listener;
+            // Call two argument add method.
+            addPropertyChangeListener(proxy.getPropertyName(),
+                                      proxy.getListener());
+        } else {
+            this.map.add(null, listener);
+        }
+    }
+
+    /**
+     * Remove a PropertyChangeListener from the listener list.
+     * This removes a PropertyChangeListener that was registered
+     * for all properties.
+     * If <code>listener</code> was added more than once to the same event
+     * source, it will be notified one less time after being removed.
+     * If <code>listener</code> is null, or was never added, no exception is
+     * thrown and no action is taken.
+     *
+     * @param listener  The PropertyChangeListener to be removed
+     */
+    public void removePropertyChangeListener(PropertyChangeListener listener) {
+        if (listener == null) {
+            return;
+        }
+        if (listener instanceof PropertyChangeListenerProxy) {
+            PropertyChangeListenerProxy proxy =
+                    (PropertyChangeListenerProxy)listener;
+            // Call two argument remove method.
+            removePropertyChangeListener(proxy.getPropertyName(),
+                                         proxy.getListener());
+        } else {
+            this.map.remove(null, listener);
+        }
+    }
+
+    /**
+     * Returns an array of all the listeners that were added to the
+     * PropertyChangeSupport object with addPropertyChangeListener().
+     * <p>
+     * If some listeners have been added with a named property, then
+     * the returned array will be a mixture of PropertyChangeListeners
+     * and <code>PropertyChangeListenerProxy</code>s. If the calling
+     * method is interested in distinguishing the listeners then it must
+     * test each element to see if it's a
+     * <code>PropertyChangeListenerProxy</code>, perform the cast, and examine
+     * the parameter.
+     *
+     * <pre>{@code
+     * PropertyChangeListener[] listeners = bean.getPropertyChangeListeners();
+     * for (int i = 0; i < listeners.length; i++) {
+     *   if (listeners[i] instanceof PropertyChangeListenerProxy) {
+     *     PropertyChangeListenerProxy proxy =
+     *                    (PropertyChangeListenerProxy)listeners[i];
+     *     if (proxy.getPropertyName().equals("foo")) {
+     *       // proxy is a PropertyChangeListener which was associated
+     *       // with the property named "foo"
+     *     }
+     *   }
+     * }
+     * }</pre>
+     *
+     * @see PropertyChangeListenerProxy
+     * @return all of the <code>PropertyChangeListeners</code> added or an
+     *         empty array if no listeners have been added
+     * @since 1.4
+     */
+    public PropertyChangeListener[] getPropertyChangeListeners() {
+        return this.map.getListeners();
+    }
+
+    /**
+     * Add a PropertyChangeListener for a specific property.  The listener
+     * will be invoked only when a call on firePropertyChange names that
+     * specific property.
+     * The same listener object may be added more than once.  For each
+     * property,  the listener will be invoked the number of times it was added
+     * for that property.
+     * If <code>propertyName</code> or <code>listener</code> is null, no
+     * exception is thrown and no action is taken.
+     *
+     * @param propertyName  The name of the property to listen on.
+     * @param listener  The PropertyChangeListener to be added
+     * @since 1.2
+     */
+    public void addPropertyChangeListener(
+                String propertyName,
+                PropertyChangeListener listener) {
+        if (listener == null || propertyName == null) {
+            return;
+        }
+        listener = this.map.extract(listener);
+        if (listener != null) {
+            this.map.add(propertyName, listener);
+        }
+    }
+
+    /**
+     * Remove a PropertyChangeListener for a specific property.
+     * If <code>listener</code> was added more than once to the same event
+     * source for the specified property, it will be notified one less time
+     * after being removed.
+     * If <code>propertyName</code> is null,  no exception is thrown and no
+     * action is taken.
+     * If <code>listener</code> is null, or was never added for the specified
+     * property, no exception is thrown and no action is taken.
+     *
+     * @param propertyName  The name of the property that was listened on.
+     * @param listener  The PropertyChangeListener to be removed
+     * @since 1.2
+     */
+    public void removePropertyChangeListener(
+                String propertyName,
+                PropertyChangeListener listener) {
+        if (listener == null || propertyName == null) {
+            return;
+        }
+        listener = this.map.extract(listener);
+        if (listener != null) {
+            this.map.remove(propertyName, listener);
+        }
+    }
+
+    /**
+     * Returns an array of all the listeners which have been associated
+     * with the named property.
+     *
+     * @param propertyName  The name of the property being listened to
+     * @return all of the <code>PropertyChangeListeners</code> associated with
+     *         the named property.  If no such listeners have been added,
+     *         or if <code>propertyName</code> is null, an empty array is
+     *         returned.
+     * @since 1.4
+     */
+    public PropertyChangeListener[] getPropertyChangeListeners(String propertyName) {
+        return this.map.getListeners(propertyName);
+    }
+
+    /**
+     * Reports a bound property update to listeners
+     * that have been registered to track updates of
+     * all properties or a property with the specified name.
+     * <p>
+     * No event is fired if old and new values are equal and non-null.
+     * <p>
+     * This is merely a convenience wrapper around the more general
+     * {@link #firePropertyChange(PropertyChangeEvent)} method.
+     *
+     * @param propertyName  the programmatic name of the property that was changed
+     * @param oldValue      the old value of the property
+     * @param newValue      the new value of the property
+     */
+    public void firePropertyChange(String propertyName, Object oldValue, Object newValue) {
+        if (oldValue == null || newValue == null || !oldValue.equals(newValue)) {
+            firePropertyChange(new PropertyChangeEvent(this.source, propertyName, oldValue, newValue));
+        }
+    }
+
+    /**
+     * Reports an integer bound property update to listeners
+     * that have been registered to track updates of
+     * all properties or a property with the specified name.
+     * <p>
+     * No event is fired if old and new values are equal.
+     * <p>
+     * This is merely a convenience wrapper around the more general
+     * {@link #firePropertyChange(String, Object, Object)}  method.
+     *
+     * @param propertyName  the programmatic name of the property that was changed
+     * @param oldValue      the old value of the property
+     * @param newValue      the new value of the property
+     * @since 1.2
+     */
+    public void firePropertyChange(String propertyName, int oldValue, int newValue) {
+        if (oldValue != newValue) {
+            firePropertyChange(propertyName, Integer.valueOf(oldValue), Integer.valueOf(newValue));
+        }
+    }
+
+    /**
+     * Reports a boolean bound property update to listeners
+     * that have been registered to track updates of
+     * all properties or a property with the specified name.
+     * <p>
+     * No event is fired if old and new values are equal.
+     * <p>
+     * This is merely a convenience wrapper around the more general
+     * {@link #firePropertyChange(String, Object, Object)}  method.
+     *
+     * @param propertyName  the programmatic name of the property that was changed
+     * @param oldValue      the old value of the property
+     * @param newValue      the new value of the property
+     * @since 1.2
+     */
+    public void firePropertyChange(String propertyName, boolean oldValue, boolean newValue) {
+        if (oldValue != newValue) {
+            firePropertyChange(propertyName, Boolean.valueOf(oldValue), Boolean.valueOf(newValue));
+        }
+    }
+
+    /**
+     * Fires a property change event to listeners
+     * that have been registered to track updates of
+     * all properties or a property with the specified name.
+     * <p>
+     * No event is fired if the given event's old and new values are equal and non-null.
+     *
+     * @param event  the {@code PropertyChangeEvent} to be fired
+     * @since 1.2
+     */
+    public void firePropertyChange(PropertyChangeEvent event) {
+        Object oldValue = event.getOldValue();
+        Object newValue = event.getNewValue();
+        if (oldValue == null || newValue == null || !oldValue.equals(newValue)) {
+            String name = event.getPropertyName();
+
+            PropertyChangeListener[] common = this.map.get(null);
+            PropertyChangeListener[] named = (name != null)
+                        ? this.map.get(name)
+                        : null;
+
+            fire(common, event);
+            fire(named, event);
+        }
+    }
+
+    private static void fire(PropertyChangeListener[] listeners, PropertyChangeEvent event) {
+        if (listeners != null) {
+            for (PropertyChangeListener listener : listeners) {
+                listener.propertyChange(event);
+            }
+        }
+    }
+
+    /**
+     * Reports a bound indexed property update to listeners
+     * that have been registered to track updates of
+     * all properties or a property with the specified name.
+     * <p>
+     * No event is fired if old and new values are equal and non-null.
+     * <p>
+     * This is merely a convenience wrapper around the more general
+     * {@link #firePropertyChange(PropertyChangeEvent)} method.
+     *
+     * @param propertyName  the programmatic name of the property that was changed
+     * @param index         the index of the property element that was changed
+     * @param oldValue      the old value of the property
+     * @param newValue      the new value of the property
+     * @since 1.5
+     */
+    public void fireIndexedPropertyChange(String propertyName, int index, Object oldValue, Object newValue) {
+        if (oldValue == null || newValue == null || !oldValue.equals(newValue)) {
+            firePropertyChange(new IndexedPropertyChangeEvent(source, propertyName, oldValue, newValue, index));
+        }
+    }
+
+    /**
+     * Reports an integer bound indexed property update to listeners
+     * that have been registered to track updates of
+     * all properties or a property with the specified name.
+     * <p>
+     * No event is fired if old and new values are equal.
+     * <p>
+     * This is merely a convenience wrapper around the more general
+     * {@link #fireIndexedPropertyChange(String, int, Object, Object)} method.
+     *
+     * @param propertyName  the programmatic name of the property that was changed
+     * @param index         the index of the property element that was changed
+     * @param oldValue      the old value of the property
+     * @param newValue      the new value of the property
+     * @since 1.5
+     */
+    public void fireIndexedPropertyChange(String propertyName, int index, int oldValue, int newValue) {
+        if (oldValue != newValue) {
+            fireIndexedPropertyChange(propertyName, index, Integer.valueOf(oldValue), Integer.valueOf(newValue));
+        }
+    }
+
+    /**
+     * Reports a boolean bound indexed property update to listeners
+     * that have been registered to track updates of
+     * all properties or a property with the specified name.
+     * <p>
+     * No event is fired if old and new values are equal.
+     * <p>
+     * This is merely a convenience wrapper around the more general
+     * {@link #fireIndexedPropertyChange(String, int, Object, Object)} method.
+     *
+     * @param propertyName  the programmatic name of the property that was changed
+     * @param index         the index of the property element that was changed
+     * @param oldValue      the old value of the property
+     * @param newValue      the new value of the property
+     * @since 1.5
+     */
+    public void fireIndexedPropertyChange(String propertyName, int index, boolean oldValue, boolean newValue) {
+        if (oldValue != newValue) {
+            fireIndexedPropertyChange(propertyName, index, Boolean.valueOf(oldValue), Boolean.valueOf(newValue));
+        }
+    }
+
+    /**
+     * Check if there are any listeners for a specific property, including
+     * those registered on all properties.  If <code>propertyName</code>
+     * is null, only check for listeners registered on all properties.
+     *
+     * @param propertyName  the property name.
+     * @return true if there are one or more listeners for the given property
+     * @since 1.2
+     */
+    public boolean hasListeners(String propertyName) {
+        return this.map.hasListeners(propertyName);
+    }
+
+    /**
+     * @serialData Null terminated list of <code>PropertyChangeListeners</code>.
+     * <p>
+     * At serialization time we skip non-serializable listeners and
+     * only serialize the serializable listeners.
+     */
+    private void writeObject(ObjectOutputStream s) throws IOException {
+        Hashtable<String, PropertyChangeSupport> children = null;
+        PropertyChangeListener[] listeners = null;
+        synchronized (this.map) {
+            for (Entry<String, PropertyChangeListener[]> entry : this.map.getEntries()) {
+                String property = entry.getKey();
+                if (property == null) {
+                    listeners = entry.getValue();
+                } else {
+                    if (children == null) {
+                        children = new Hashtable<>();
+                    }
+                    PropertyChangeSupport pcs = new PropertyChangeSupport(this.source);
+                    pcs.map.set(null, entry.getValue());
+                    children.put(property, pcs);
+                }
+            }
+        }
+        ObjectOutputStream.PutField fields = s.putFields();
+        fields.put("children", children);
+        fields.put("source", this.source);
+        fields.put("propertyChangeSupportSerializedDataVersion", 2);
+        s.writeFields();
+
+        if (listeners != null) {
+            for (PropertyChangeListener l : listeners) {
+                if (l instanceof Serializable) {
+                    s.writeObject(l);
+                }
+            }
+        }
+        s.writeObject(null);
+    }
+
+    private void readObject(ObjectInputStream s) throws ClassNotFoundException, IOException {
+        this.map = new PropertyChangeListenerMap();
+
+        ObjectInputStream.GetField fields = s.readFields();
+
+        @SuppressWarnings("unchecked")
+        Hashtable<String, PropertyChangeSupport> children = (Hashtable<String, PropertyChangeSupport>) fields.get("children", null);
+        this.source = fields.get("source", null);
+        fields.get("propertyChangeSupportSerializedDataVersion", 2);
+
+        Object listenerOrNull;
+        while (null != (listenerOrNull = s.readObject())) {
+            this.map.add(null, (PropertyChangeListener)listenerOrNull);
+        }
+        if (children != null) {
+            for (Entry<String, PropertyChangeSupport> entry : children.entrySet()) {
+                for (PropertyChangeListener listener : entry.getValue().getPropertyChangeListeners()) {
+                    this.map.add(entry.getKey(), listener);
+                }
+            }
+        }
+    }
+
+    /**
+     * The object to be provided as the "source" for any generated events.
+     */
+    private Object source;
+
+    /**
+     * @serialField children                                   Hashtable
+     * @serialField source                                     Object
+     * @serialField propertyChangeSupportSerializedDataVersion int
+     */
+    private static final ObjectStreamField[] serialPersistentFields = {
+            new ObjectStreamField("children", Hashtable.class),
+            new ObjectStreamField("source", Object.class),
+            new ObjectStreamField("propertyChangeSupportSerializedDataVersion", Integer.TYPE)
+    };
+
+    /**
+     * Serialization version ID, so we're compatible with JDK 1.1
+     */
+    static final long serialVersionUID = 6401253773779951803L;
+
+    /**
+     * This is a {@link ChangeListenerMap ChangeListenerMap} implementation
+     * that works with {@link PropertyChangeListener PropertyChangeListener} objects.
+     */
+    private static final class PropertyChangeListenerMap extends ChangeListenerMap<PropertyChangeListener> {
+        private static final PropertyChangeListener[] EMPTY = {};
+
+        /**
+         * Creates an array of {@link PropertyChangeListener PropertyChangeListener} objects.
+         * This method uses the same instance of the empty array
+         * when {@code length} equals {@code 0}.
+         *
+         * @param length  the array length
+         * @return        an array with specified length
+         */
+        @Override
+        protected PropertyChangeListener[] newArray(int length) {
+            return (0 < length)
+                    ? new PropertyChangeListener[length]
+                    : EMPTY;
+        }
+
+        /**
+         * Creates a {@link PropertyChangeListenerProxy PropertyChangeListenerProxy}
+         * object for the specified property.
+         *
+         * @param name      the name of the property to listen on
+         * @param listener  the listener to process events
+         * @return          a {@code PropertyChangeListenerProxy} object
+         */
+        @Override
+        protected PropertyChangeListener newProxy(String name, PropertyChangeListener listener) {
+            return new PropertyChangeListenerProxy(name, listener);
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        public final PropertyChangeListener extract(PropertyChangeListener listener) {
+            while (listener instanceof PropertyChangeListenerProxy) {
+                listener = ((PropertyChangeListenerProxy) listener).getListener();
+            }
+            return listener;
+        }
+    }
+}