Java example source code file (WScrollbarPeer.java)

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Java - Java tags/keywords

adjustmentevent, awt, dimension, event, runnable, scrollbar, wcomponentpeer, wscrollbarpeer

The WScrollbarPeer.java Java example source code

/*
 * Copyright (c) 1996, 2013, 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.awt.windows;

import java.awt.*;
import java.awt.peer.*;
import java.awt.event.AdjustmentEvent;

final class WScrollbarPeer extends WComponentPeer implements ScrollbarPeer {

    // Returns width for vertial scrollbar as SM_CXHSCROLL,
    // height for horizontal scrollbar as SM_CYVSCROLL
    static native int getScrollbarSize(int orientation);

    // ComponentPeer overrides
    public Dimension getMinimumSize() {
        if (((Scrollbar)target).getOrientation() == Scrollbar.VERTICAL) {
            return new Dimension(getScrollbarSize(Scrollbar.VERTICAL), 50);
        }
        else {
            return new Dimension(50, getScrollbarSize(Scrollbar.HORIZONTAL));
        }
    }

    // ScrollbarPeer implementation

    public native void setValues(int value, int visible,
                                 int minimum, int maximum);
    public native void setLineIncrement(int l);
    public native void setPageIncrement(int l);


    // Toolkit & peer internals

    WScrollbarPeer(Scrollbar target) {
        super(target);
    }

    native void create(WComponentPeer parent);

    void initialize() {
        Scrollbar sb = (Scrollbar)target;
        setValues(sb.getValue(), sb.getVisibleAmount(),
                  sb.getMinimum(), sb.getMaximum());
        super.initialize();
    }


    // NOTE: Callback methods are called by privileged threads.
    //       DO NOT INVOKE CLIENT CODE ON THIS THREAD!

    private void postAdjustmentEvent(final int type, final int value,
                                     final boolean isAdjusting)
    {
        final Scrollbar sb = (Scrollbar)target;
        WToolkit.executeOnEventHandlerThread(sb, new Runnable() {
            public void run() {
                sb.setValueIsAdjusting(isAdjusting);
                sb.setValue(value);
                postEvent(new AdjustmentEvent(sb,
                                AdjustmentEvent.ADJUSTMENT_VALUE_CHANGED,
                                type, value, isAdjusting));
            }
        });
    }

    void lineUp(int value) {
        postAdjustmentEvent(AdjustmentEvent.UNIT_DECREMENT, value, false);
    }

    void lineDown(int value) {
        postAdjustmentEvent(AdjustmentEvent.UNIT_INCREMENT, value, false);
    }

    void pageUp(int value) {
        postAdjustmentEvent(AdjustmentEvent.BLOCK_DECREMENT, value, false);
    }

    void pageDown(int value) {
        postAdjustmentEvent(AdjustmentEvent.BLOCK_INCREMENT, value, false);
    }

    // SB_TOP/BOTTOM are mapped to tracking
    void warp(int value) {
        postAdjustmentEvent(AdjustmentEvent.TRACK, value, false);
    }

    private boolean dragInProgress = false;

    void drag(final int value) {
        if (!dragInProgress) {
            dragInProgress = true;
        }
        postAdjustmentEvent(AdjustmentEvent.TRACK, value, true);
    }

    void dragEnd(final int value) {
        final Scrollbar sb = (Scrollbar)target;

        if (!dragInProgress) {
            return;
        }

        dragInProgress = false;
        WToolkit.executeOnEventHandlerThread(sb, new Runnable() {
            public void run() {
                // NB: notification only, no sb.setValue()
                // last TRACK event will have done it already
                sb.setValueIsAdjusting(false);
                postEvent(new AdjustmentEvent(sb,
                                AdjustmentEvent.ADJUSTMENT_VALUE_CHANGED,
                                AdjustmentEvent.TRACK, value, false));
            }
        });
    }

    public boolean shouldClearRectBeforePaint() {
        return false;
    }
}