Java example source code file (CAccessible.java)

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Java - Java tags/keywords

accessible, accessiblecontext, awt, axprogresschangenotifier, axtextchangenotifier, caccessible, caretlistener, cfretainedresource, changelistener, event, exception, field, gui, jprogressbar, jslider, jtextcomponent, override, reflection, swing, text

The CAccessible.java Java example source code

/*
 * Copyright (c) 2011, 2012, 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 sun.lwawt.macosx;

import java.awt.Component;
import java.lang.reflect.Field;

import javax.accessibility.Accessible;
import javax.accessibility.AccessibleContext;
import javax.swing.JProgressBar;
import javax.swing.JSlider;
import javax.swing.event.CaretEvent;
import javax.swing.event.CaretListener;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.JTextComponent;


class CAccessible extends CFRetainedResource implements Accessible {
    static Field getNativeAXResourceField() {
        try {
            final Field field = AccessibleContext.class.getDeclaredField("nativeAXResource");
            field.setAccessible(true);
            return field;
        } catch (final Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    private static Field nativeAXResourceField = getNativeAXResourceField();

    public static CAccessible getCAccessible(final Accessible a) {
        if (a == null) return null;
        AccessibleContext context = a.getAccessibleContext();
        try {
            final CAccessible cachedCAX = (CAccessible) nativeAXResourceField.get(context);
            if (cachedCAX != null) return cachedCAX;

            final CAccessible newCAX = new CAccessible(a);
            nativeAXResourceField.set(context, newCAX);
            return newCAX;
        }  catch (final Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    private static native void unregisterFromCocoaAXSystem(long ptr);
    private static native void valueChanged(long ptr);
    private static native void selectionChanged(long ptr);

    private Accessible accessible;

    private CAccessible(final Accessible accessible) {
        super(0L, true); // real pointer will be poked in by native

        if (accessible == null) throw new NullPointerException();
        this.accessible = accessible;

        if (accessible instanceof Component) {
            addNotificationListeners((Component)accessible);
        }
    }

    @Override
    protected synchronized void dispose() {
        if (ptr != 0) unregisterFromCocoaAXSystem(ptr);
        super.dispose();
    }

    @Override
    public AccessibleContext getAccessibleContext() {
        return accessible.getAccessibleContext();
    }

    // currently only supports text components
    public void addNotificationListeners(Component c) {
        if (c instanceof JTextComponent) {
            JTextComponent tc = (JTextComponent) c;
            AXTextChangeNotifier listener = new AXTextChangeNotifier();
            tc.getDocument().addDocumentListener(listener);
            tc.addCaretListener(listener);
        }
        if (c instanceof JProgressBar) {
            JProgressBar pb = (JProgressBar) c;
            pb.addChangeListener(new AXProgressChangeNotifier());
        } else if (c instanceof JSlider) {
            JSlider slider = (JSlider) c;
            slider.addChangeListener(new AXProgressChangeNotifier());
        }
    }


    private class AXTextChangeNotifier implements DocumentListener, CaretListener {
        @Override
        public void changedUpdate(DocumentEvent e) {
            if (ptr != 0) valueChanged(ptr);
        }

        @Override
        public void insertUpdate(DocumentEvent e) {
            if (ptr != 0) valueChanged(ptr);
        }

        @Override
        public void removeUpdate(DocumentEvent e) {
            if (ptr != 0) valueChanged(ptr);
        }

        @Override
        public void caretUpdate(CaretEvent e) {
            if (ptr != 0) selectionChanged(ptr);
        }
    }

    private class AXProgressChangeNotifier implements ChangeListener {
        public void stateChanged(ChangeEvent e) {
            if (ptr != 0) valueChanged(ptr);
        }
    }

    static Accessible getSwingAccessible(final Accessible a) {
        return (a instanceof CAccessible) ? ((CAccessible)a).accessible : a;
    }
}