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Diffstat (limited to 'libjava/classpath/java/util/Observable.java')
-rw-r--r-- | libjava/classpath/java/util/Observable.java | 182 |
1 files changed, 0 insertions, 182 deletions
diff --git a/libjava/classpath/java/util/Observable.java b/libjava/classpath/java/util/Observable.java deleted file mode 100644 index 916abe4..0000000 --- a/libjava/classpath/java/util/Observable.java +++ /dev/null @@ -1,182 +0,0 @@ -/* Observable.java -- an object to be observed - Copyright (C) 1999, 2000, 2001, 2002, 2005 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.util; - -/** - * This class represents an object which is observable. Other objects may - * register their intent to be notified when this object changes; and when - * this object does change, it will trigger the <code>update</code> method - * of each observer. - * - * Note that the <code>notifyObservers()</code> method of this class is - * unrelated to the <code>notify()</code> of Object. - * - * @author Warren Levy (warrenl@cygnus.com) - * @author Eric Blake (ebb9@email.byu.edu) - * @see Observer - * @status updated to 1.4 - */ -public class Observable -{ - /** Tracks whether this object has changed. */ - private boolean changed; - - /* List of the Observers registered as interested in this Observable. */ - private LinkedHashSet observers; - - /** - * Constructs an Observable with zero Observers. - */ - public Observable() - { - observers = new LinkedHashSet(); - } - - /** - * Adds an Observer. If the observer was already added this method does - * nothing. - * - * @param observer Observer to add - * @throws NullPointerException if observer is null - */ - public synchronized void addObserver(Observer observer) - { - if (observer == null) - throw new NullPointerException("can't add null observer"); - observers.add(observer); - } - - /** - * Reset this Observable's state to unchanged. This is called automatically - * by <code>notifyObservers</code> once all observers have been notified. - * - * @see #notifyObservers() - */ - protected synchronized void clearChanged() - { - changed = false; - } - - /** - * Returns the number of observers for this object. - * - * @return number of Observers for this - */ - public synchronized int countObservers() - { - return observers.size(); - } - - /** - * Deletes an Observer of this Observable. - * - * @param victim Observer to delete - */ - public synchronized void deleteObserver(Observer victim) - { - observers.remove(victim); - } - - /** - * Deletes all Observers of this Observable. - */ - public synchronized void deleteObservers() - { - observers.clear(); - } - - /** - * True if <code>setChanged</code> has been called more recently than - * <code>clearChanged</code>. - * - * @return whether or not this Observable has changed - */ - public synchronized boolean hasChanged() - { - return changed; - } - - /** - * If the Observable has actually changed then tell all Observers about it, - * then reset state to unchanged. - * - * @see #notifyObservers(Object) - * @see Observer#update(Observable, Object) - */ - public void notifyObservers() - { - notifyObservers(null); - } - - /** - * If the Observable has actually changed then tell all Observers about it, - * then reset state to unchanged. Note that though the order of - * notification is unspecified in subclasses, in Observable it is in the - * order of registration. - * - * @param obj argument to Observer's update method - * @see Observer#update(Observable, Object) - */ - public void notifyObservers(Object obj) - { - if (! hasChanged()) - return; - // Create clone inside monitor, as that is relatively fast and still - // important to keep threadsafe, but update observers outside of the - // lock since update() can call arbitrary code. - Set s; - synchronized (this) - { - s = (Set) observers.clone(); - } - int i = s.size(); - Iterator iter = s.iterator(); - while (--i >= 0) - ((Observer) iter.next()).update(this, obj); - clearChanged(); - } - - /** - * Marks this Observable as having changed. - */ - protected synchronized void setChanged() - { - changed = true; - } -} |