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authorSascha Brawer <brawer@dandelis.ch>2004-01-07 15:42:04 +0100
committerMichael Koch <mkoch@gcc.gnu.org>2004-01-07 14:42:04 +0000
commitb3db7ef158c0e7b8bde40aa4c962d16d255c3ffd (patch)
treec031ffd0a3d166fbfd7642e5bd4082ad4a86b79c /libjava/javax/swing/event
parentb48a0c1869fe5fe1508efa31f80dd11f0d3fdef0 (diff)
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DefaultBoundedRangeModel.java: Documented API.
2004-01-07 Sascha Brawer <brawer@dandelis.ch> * javax/swing/DefaultBoundedRangeModel.java: Documented API. (changeEvent): Create event object on demand. (DefaultBoundedRangeModel, toString, setValue, setExtent, setMinimum, setMaximum, setValueIsAdjusting, setRangeProperties, fireStateChanged): Re-written. * javax/swing/event/EventListenerList.java: Reformatted, document typical usage. (toString): Implemented. (getListeners): Re-written. (remove): Re-written. (add): Re-written. (NO_LISTENERS): New singleton field. (listenerList): Declare as transient; document. (serialVersionUID): Document. (getListenerCount(Class)): More efficient implementation, also accepts null argument. Improve Javadoc. (getListenerCount()): Remove unnecessary cast; docfix. * javax/swing/undo/UndoableEditSupport.java: Re-format, document. (UndoableEditSupport): Set realSource field. Improve documentation. (_postEdit): Iterate over cloned listener vector. (toString): Don't emit realSource. (beginUpdate, endUpdate): Support nested updates. (postEdit): Use compound edit if present. From-SVN: r75505
Diffstat (limited to 'libjava/javax/swing/event')
-rw-r--r--libjava/javax/swing/event/EventListenerList.java452
1 files changed, 256 insertions, 196 deletions
diff --git a/libjava/javax/swing/event/EventListenerList.java b/libjava/javax/swing/event/EventListenerList.java
index 1197ccb..e7294af 100644
--- a/libjava/javax/swing/event/EventListenerList.java
+++ b/libjava/javax/swing/event/EventListenerList.java
@@ -1,5 +1,5 @@
/* EventListenerList.java --
- Copyright (C) 2002 Free Software Foundation, Inc.
+ Copyright (C) 2002, 2004 Free Software Foundation, Inc.
This file is part of GNU Classpath.
@@ -37,206 +37,266 @@ exception statement from your version. */
package javax.swing.event;
-// Imports
import java.io.Serializable;
+import java.lang.reflect.Array;
import java.util.EventListener;
+
/**
- * EventListenerList
- * @author Andrew Selkirk
+ * A utility class for keeping track of {@link EventListener}s.
+ *
+ * <p><b>Example for using this class:</b>
+ *
+ * <blockquote><pre> import java.util.EventListener;
+ * import javax.swing.event.EventListenerList;
+ *
+ * class Foo
+ * {
+ * protected final EventListenerList listeners = new EventListenerList();
+ * protected BarClosedEvent barClosedEvent = null;
+ *
+ * public void addBarListener(BarListener l)
+ * {
+ * listeners.<a href="#add(java.lang.Class, java.util.EventListener)"
+ * >add</a>(BarListener.class, l);
+ * }
+ *
+ * public void removeBarListener(BarListener l)
+ * {
+ * listeners.<a href="#remove(java.lang.Class, java.util.EventListener)"
+ * >remove</a>(BarListener.class, l);
+ * }
+ *
+ * protected void fireBarClosedEvent()
+ * {
+ * Object[] l = listeners.<a href="#getListenerList()"
+ * >getListenerList()</a>;
+ *
+ * for (int i = l.length - 2; i >= 0; i -= 2)
+ * if (l[i] == BarListener.class)
+ * {
+ * // Create the event on demand, when it is needed the first time.
+ * if (barClosedEvent == null)
+ * barClosedEvent = new BarClosedEvent(this);
+ *
+ * ((BarClosedListener) l[i + 1]).barClosed(barClosedEvent);
+ * }
+ * }
+ * }</pre></blockquote>
+ *
+ * @author <a href="mailto:aselkirk@sympatico.ca">Andrew Selkirk</a>
+ * @author <a href="mailto:brawer@dandelis.ch">Sascha Brawer</a>
*/
-public class EventListenerList extends Object implements Serializable
+public class EventListenerList
+ implements Serializable
{
+ /**
+ * An ID for serializing instances of this class; verified with the
+ * serialver tool of Sun J2SE 1.4.1_01.
+ */
static final long serialVersionUID = -5677132037850737084L;
- //-------------------------------------------------------------
- // Variables --------------------------------------------------
- //-------------------------------------------------------------
-
- /**
- * Listener list
- */
- protected Object[] listenerList = null;
-
-
- //-------------------------------------------------------------
- // Initialization ---------------------------------------------
- //-------------------------------------------------------------
-
- /**
- * EventListenerList constructor
- */
- public EventListenerList() {
- listenerList = new Object[0];
- } // EventListenerList()
-
-
- //-------------------------------------------------------------
- // Methods ----------------------------------------------------
- //-------------------------------------------------------------
-
- /**
- * Add Listener
- * @param t Class type
- * @param listener Listener to add
- */
- public void add(Class t, EventListener listener) {
-
- // Variables
- Object[] list;
- int index;
- Class checkClass;
- EventListener checkListener;
-
- // Create New list in anticipation that listener is not present
- list = new Object[listenerList.length + 2];
-
- // Search through list looking for listener
- for (index = 0; index < listenerList.length; index += 2) {
- checkClass = (Class) listenerList[index];
- checkListener = (EventListener) listenerList[index + 1];
- if (checkClass.equals(t) == true &&
- checkListener.equals(listener) == true) {
- return;
- } // if
- } // for
-
- // Add Listener
- list[listenerList.length] = t;
- list[listenerList.length + 1] = listener;
-
- // Replace Listener List
- listenerList = list;
-
- } // add()
-
- /**
- * Get the total number of listeners
- * @return Count of listeners
- */
- public int getListenerCount() {
- return (int) listenerList.length / 2;
- } // getListenerCount
-
- /**
- * Get the number of listeners of a particular type
- * @param t Class type to count
- * @returns Count of the specified listeners
- */
- public int getListenerCount(Class t) {
-
- // Variables
- int index;
- int count;
- String name;
-
- // Loop through entire list
- count = 0;
- name = t.getName();
- for (index = 0; index < listenerList.length; index += 2) {
- if (((Class) listenerList[index]).getName().equals(name) == true) {
- count += 1;
- }
- } // for: index
-
- // Return Count
- return count;
-
- } // getListenerCount()
-
- /**
- * Get a list of listenerType/listener pairs
- * @returns Listener list
- */
- public Object[] getListenerList() {
- return listenerList;
- } // getListenerList()
-
- /**
- * Get list of listeners of a particular type
- * @param c Class type
- * @returns List of listeners of the specified type
- */
- public EventListener[] getListeners(Class c) {
-
- // Variables
- int count;
- EventListener[] list;
- String name;
- int index;
-
- // Get count of listeners
- count = getListenerCount(c);
-
- // Create Event Listener list
- list = new EventListener[count];
-
- // Construct List
- count = 0;
- name = c.getName();
- for (index = 0; index < listenerList.length; index += 2) {
- if (((Class) listenerList[index]).getName().equals(name) == true) {
- list[count] = (EventListener) listenerList[index];
- count += 1;
- } // if
- } // for: index
-
- // Return List
- return list;
-
- } // getListeners()
-
- /**
- * Remove a listener
- * @param t Class type
- * @param listener Listener to be removed
- */
- public void remove(Class t, EventListener listener) {
-
- // Variables
- Object[] list;
- int index;
- Class checkClass;
- EventListener checkListener;
- int pointer;
- boolean found;
-
- // Create New list in anticipation that listener is not present
- if (listenerList.length == 0) {
- return;
- } // if
- list = new Object[listenerList.length - 2];
-
- // Search through list looking for listener
- pointer = 0;
- found = false;
- for (index = 0; index < listenerList.length - 2; index += 2) {
- checkClass = (Class) listenerList[index];
- checkListener = (EventListener) listenerList[index + 1];
- if (checkClass.equals(t) == false ||
- checkListener.equals(listener) == false) {
- list[pointer] = checkClass;
- list[pointer + 1] = checkListener;
- pointer += 2;
- } else {
- found = true;
- } // if
- } // for
-
- // Replace Listener List
- if (found == true) {
- listenerList = list;
- } // if
-
- } // remove()
-
- /**
- * Get a string representation
- * @returns String representation
- */
- public String toString() {
- return null; // TODO
- } // toString()
-
-
-} // EventListenerList
+
+ /**
+ * An empty array that is shared by all instances of this class that
+ * have no listeners.
+ */
+ private static final Object[] NO_LISTENERS = new Object[0];
+
+
+ /**
+ * An array with all currently registered listeners. The array has
+ * twice as many elements as there are listeners. For an even
+ * integer <code>i</code>, <code>listenerList[i]</code> indicates
+ * the registered class, and <code>listenerList[i+1]</code> is the
+ * listener.
+ */
+ protected transient Object[] listenerList = NO_LISTENERS;
+
+
+ /**
+ * EventListenerList constructor
+ */
+ public EventListenerList()
+ {
+ }
+
+
+ /**
+ * Registers a listener of a specific type.
+ *
+ * @param t the type of the listener.
+ *
+ * @param listener the listener to add, which must be an instance of
+ * <code>t</code>, or of a subclass of <code>t</code>.
+ *
+ * @throws IllegalArgumentException if <code>listener</code> is not
+ * an instance of <code>t</code> (or a subclass thereof).
+ *
+ * @throws Exception if <code>t</code> is <code>null</code>.
+ */
+ public void add(Class t, EventListener listener)
+ {
+ int oldLength;
+ Object[] newList;
+
+ if (listener == null)
+ return;
+
+ if (!t.isInstance(listener))
+ throw new IllegalArgumentException();
+
+ oldLength = listenerList.length;
+ newList = new Object[oldLength + 2];
+ if (oldLength > 0)
+ System.arraycopy(listenerList, 0, newList, 0, oldLength);
+
+ newList[oldLength] = t;
+ newList[oldLength + 1] = listener;
+ listenerList = newList;
+ }
+
+
+ /**
+ * Determines the number of listeners.
+ */
+ public int getListenerCount()
+ {
+ return listenerList.length / 2;
+ }
+
+
+ /**
+ * Determines the number of listeners of a particular class.
+ *
+ * @param t the type of listeners to be counted. In order to get
+ * counted, a subscribed listener must be exactly of class
+ * <code>t</code>. Thus, subclasses of <code>t</code> will not be
+ * counted.
+ */
+ public int getListenerCount(Class t)
+ {
+ int result = 0;
+ for (int i = 0; i < listenerList.length; i += 2)
+ if (t == listenerList[i])
+ ++result;
+
+ return result;
+ }
+
+
+ /**
+ * Get a list of listenerType/listener pairs
+ * @returns Listener list
+ */
+ public Object[] getListenerList()
+ {
+ return listenerList;
+ }
+
+
+ /**
+ * Retrieves the currently subscribed listeners of a particular
+ * type. For a listener to be returned, it must have been
+ * registered with exactly the type <code>c</code>; subclasses are
+ * not considered equal.
+ *
+ * <p>The returned array can always be cast to <code>c[]</code>.
+ * Since it is a newly allocated copy, the caller may arbitrarily
+ * modify the array.
+ *
+ * @param c the class which was passed to {@link #add}.
+ *
+ * @throws ClassCastException if <code>c</code> does not implement
+ * the {@link EventListener} interface.
+ *
+ * @throws NullPointerException if <code>c</code> is
+ * <code>null</code>.
+ *
+ * @returns an array of <code>c</code> whose elements are the
+ * currently subscribed listeners of the specified type. If there
+ * are no such listeners, an empty array is returned.
+ *
+ * @since 1.3
+ */
+ public EventListener[] getListeners(Class c)
+ {
+ int count, f;
+ EventListener[] result;
+
+ count = getListenerCount(c);
+ result = (EventListener[]) Array.newInstance(c, count);
+ f = 0;
+ for (int i = 0; i < listenerList.length; i += 2)
+ if (listenerList[i] == c)
+ result[f++] = (EventListener) listenerList[i + 1];
+
+ return result;
+ }
+
+
+ /**
+ * Removes a listener of a specific type.
+ *
+ * @param t the type of the listener.
+ *
+ * @param listener the listener to remove, which must be an instance
+ * of <code>t</code>, or of a subclass of <code>t</code>.
+ *
+ * @throws IllegalArgumentException if <code>listener</code> is not
+ * an instance of <code>t</code> (or a subclass thereof).
+ *
+ * @throws Exception if <code>t</code> is <code>null</code>.
+ */
+ public void remove(Class t, EventListener listener)
+ {
+ Object[] oldList, newList;
+ int oldLength;
+
+ if (listener == null)
+ return;
+
+ if (!t.isInstance(listener))
+ throw new IllegalArgumentException();
+
+ oldList = listenerList;
+ oldLength = oldList.length;
+ for (int i = 0; i < oldLength; i += 2)
+ if (oldList[i] == t && oldList[i + 1] == listener)
+ {
+ if (oldLength == 2)
+ newList = NO_LISTENERS;
+ else
+ {
+ newList = new Object[oldLength - 2];
+ if (i > 0)
+ System.arraycopy(oldList, 0, newList, 0, i);
+ if (i < oldLength - 2)
+ System.arraycopy(oldList, i + 2, newList, i,
+ oldLength - 2 - i);
+ }
+ listenerList = newList;
+ return;
+ }
+ }
+
+
+ /**
+ * Returns a string representation of this object that may be useful
+ * for debugging purposes.
+ */
+ public String toString()
+ {
+ StringBuffer buf = new StringBuffer("EventListenerList: ");
+ buf.append(listenerList.length / 2);
+ buf.append(" listeners: ");
+ for (int i = 0; i < listenerList.length; i += 2)
+ {
+ buf.append(" type ");
+ buf.append(((Class) listenerList[i]).getName());
+ buf.append(" listener ");
+ buf.append(listenerList[i + 1]);
+ }
+ return buf.toString();
+ }
+}
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