1 /*
2 * Copyright (c) 1994, 2004, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
27
28 /**
29 * This class represents an observable object, or "data"
30 * in the model-view paradigm. It can be subclassed to represent an
31 * object that the application wants to have observed.
32 * <p>
33 * An observable object can have one or more observers. An observer
34 * may be any object that implements interface <tt>Observer</tt>. After an
35 * observable instance changes, an application calling the
36 * <code>Observable</code>'s <code>notifyObservers</code> method
37 * causes all of its observers to be notified of the change by a call
38 * to their <code>update</code> method.
39 * <p>
40 * The order in which notifications will be delivered is unspecified.
41 * The default implementation provided in the Observable class will
42 * notify Observers in the order in which they registered interest, but
43 * subclasses may change this order, use no guaranteed order, deliver
44 * notifications on separate threads, or may guarantee that their
45 * subclass follows this order, as they choose.
46 * <p>
47 * Note that this notification mechanism is has nothing to do with threads
48 * and is completely separate from the <tt>wait</tt> and <tt>notify</tt>
49 * mechanism of class <tt>Object</tt>.
50 * <p>
51 * When an observable object is newly created, its set of observers is
52 * empty. Two observers are considered the same if and only if the
53 * <tt>equals</tt> method returns true for them.
54 *
55 * @author Chris Warth
56 * @see java.util.Observable#notifyObservers()
57 * @see java.util.Observable#notifyObservers(java.lang.Object)
58 * @see java.util.Observer
59 * @see java.util.Observer#update(java.util.Observable, java.lang.Object)
60 * @since JDK1.0
61 */
62 public class Observable {
63 private boolean changed = false;
64 private Vector obs;
65
66 /** Construct an Observable with zero Observers. */
67
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1 /*
2 * Copyright (c) 1994, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
27
28 /**
29 * This class represents an observable object, or "data"
30 * in the model-view paradigm. It can be subclassed to represent an
31 * object that the application wants to have observed.
32 * <p>
33 * An observable object can have one or more observers. An observer
34 * may be any object that implements interface <tt>Observer</tt>. After an
35 * observable instance changes, an application calling the
36 * <code>Observable</code>'s <code>notifyObservers</code> method
37 * causes all of its observers to be notified of the change by a call
38 * to their <code>update</code> method.
39 * <p>
40 * The order in which notifications will be delivered is unspecified.
41 * The default implementation provided in the Observable class will
42 * notify Observers in the order in which they registered interest, but
43 * subclasses may change this order, use no guaranteed order, deliver
44 * notifications on separate threads, or may guarantee that their
45 * subclass follows this order, as they choose.
46 * <p>
47 * Note that this notification mechanism has nothing to do with threads
48 * and is completely separate from the <tt>wait</tt> and <tt>notify</tt>
49 * mechanism of class <tt>Object</tt>.
50 * <p>
51 * When an observable object is newly created, its set of observers is
52 * empty. Two observers are considered the same if and only if the
53 * <tt>equals</tt> method returns true for them.
54 *
55 * @author Chris Warth
56 * @see java.util.Observable#notifyObservers()
57 * @see java.util.Observable#notifyObservers(java.lang.Object)
58 * @see java.util.Observer
59 * @see java.util.Observer#update(java.util.Observable, java.lang.Object)
60 * @since JDK1.0
61 */
62 public class Observable {
63 private boolean changed = false;
64 private Vector obs;
65
66 /** Construct an Observable with zero Observers. */
67
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