Исходный код

001/*
002 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation.  Oracle designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Oracle in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
022 * or visit www.oracle.com if you need additional information or have any
023 * questions.
024 */
025
026package javafx.beans.value;
027
028import java.util.ArrayList;
029import java.util.List;
030
031import com.sun.javafx.binding.ExpressionHelper;
032import javafx.beans.InvalidationListener;
033import javafx.beans.Observable;
034
035/**
036 * A convenience class for creating implementations of {@link ObservableValue}.
037 * It contains all of the infrastructure support for value invalidation- and
038 * change event notification.
039 * 
040 * This implementation can handle adding and removing listeners while the
041 * observers are being notified, but it is not thread-safe.
042 * 
043 * 
044 */
045public abstract class ObservableValueBase<T> implements ObservableValue<T> {
046
047    private ExpressionHelper<T> helper;
048
049    /**
050     * {@inheritDoc}
051     */
052    @Override
053    public void addListener(InvalidationListener listener) {
054        helper = ExpressionHelper.addListener(helper, this, listener);
055    }
056
057    /**
058     * {@inheritDoc}
059     */
060    @Override
061    public void addListener(ChangeListener<? super T> listener) {
062        helper = ExpressionHelper.addListener(helper, this, listener);
063    }
064
065    /**
066     * {@inheritDoc}
067     */
068    @Override
069    public void removeListener(InvalidationListener listener) {
070        helper = ExpressionHelper.removeListener(helper, listener);
071    }
072
073    /**
074     * {@inheritDoc}
075     */
076    @Override
077    public void removeListener(ChangeListener<? super T> listener) {
078        helper = ExpressionHelper.removeListener(helper, listener);
079    }
080
081    /**
082     * Notify the currently registered observers of a value change.
083     * 
084     * This implementation will ignore all adds and removes of observers that
085     * are done while a notification is processed. The changes take effect in
086     * the following call to fireValueChangedEvent.
087     */
088    protected void fireValueChangedEvent() {
089        ExpressionHelper.fireValueChangedEvent(helper);
090    }
091}