com.aptana.ui.console.ConsoleAutoScrollPageParticipant.java Source code

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Here is the source code for com.aptana.ui.console.ConsoleAutoScrollPageParticipant.java

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/**
 * Aptana Studio
 * Copyright (c) 2005-2012 by Appcelerator, Inc. All Rights Reserved.
 * Licensed under the terms of the GNU Public License (GPL) v3 (with exceptions).
 * Please see the license.html included with this distribution for details.
 * Any modifications to this file must keep this entire header intact.
 */
package com.aptana.ui.console;

import org.eclipse.core.runtime.PlatformObject;
import org.eclipse.debug.ui.IDebugUIConstants;
import org.eclipse.jface.action.ActionContributionItem;
import org.eclipse.jface.action.IAction;
import org.eclipse.jface.action.IContributionItem;
import org.eclipse.jface.action.IToolBarManager;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.StyledText;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.ScrollBar;
import org.eclipse.ui.console.IConsole;
import org.eclipse.ui.console.IConsolePageParticipant;
import org.eclipse.ui.console.TextConsolePage;
import org.eclipse.ui.console.TextConsoleViewer;
import org.eclipse.ui.internal.console.IOConsoleViewer;
import org.eclipse.ui.internal.console.ScrollLockAction;
import org.eclipse.ui.part.IPageBookViewPage;

/**
 * @author Shalom
 */
@SuppressWarnings("restriction")
public class ConsoleAutoScrollPageParticipant extends PlatformObject implements IConsolePageParticipant {
    private boolean scrollActionEnabled;
    private StyledText textWidget;
    private Listener listener;

    /*
     * (non-Javadoc)
     * @see org.eclipse.ui.console.IConsolePageParticipant#init(org.eclipse.ui.part.IPageBookViewPage,
     * org.eclipse.ui.console.IConsole)
     */
    public void init(IPageBookViewPage page, IConsole console) {
        if (console.getType() != IDebugUIConstants.ID_PROCESS_CONSOLE_TYPE || !(page instanceof TextConsolePage)) {
            return;
        }
        TextConsolePage consolePage = (TextConsolePage) page;
        TextConsoleViewer textViewer = consolePage.getViewer();
        if (!(textViewer instanceof IOConsoleViewer)) {
            return;
        }
        final IOConsoleViewer viewer = (IOConsoleViewer) textViewer;
        scrollActionEnabled = viewer.isAutoScroll();
        final IToolBarManager toolBarManager = consolePage.getSite().getActionBars().getToolBarManager();
        IAction slAction = null;
        // Look for the ScrollLockAction
        for (IContributionItem item : toolBarManager.getItems()) {
            if (item instanceof ActionContributionItem) {
                IAction action = ((ActionContributionItem) item).getAction();
                if (action instanceof ScrollLockAction) {
                    slAction = action;
                    break;
                }
            }
        }
        textWidget = viewer.getTextWidget();
        listener = new ConsoleListener(viewer, toolBarManager, slAction);

        // Based on Eclipse Snippet191 - Detects scrolling that were initiated by the user.
        textWidget.addListener(SWT.MouseDown, listener);
        textWidget.addListener(SWT.MouseMove, listener);
        textWidget.addListener(SWT.MouseUp, listener);
        textWidget.addListener(SWT.KeyDown, listener);
        textWidget.addListener(SWT.KeyUp, listener);
        textWidget.addListener(SWT.Resize, listener);
        ScrollBar vBar = textWidget.getVerticalBar();
        if (vBar != null) {
            vBar.addListener(SWT.Selection, listener);
        }
    }

    /*
     * (non-Javadoc)
     * @see org.eclipse.ui.console.IConsolePageParticipant#dispose()
     */
    public void dispose() {
        if (textWidget != null && !textWidget.isDisposed()) {
            textWidget.removeListener(SWT.MouseDown, listener);
            textWidget.removeListener(SWT.MouseMove, listener);
            textWidget.removeListener(SWT.MouseUp, listener);
            textWidget.removeListener(SWT.KeyDown, listener);
            textWidget.removeListener(SWT.KeyUp, listener);
            textWidget.removeListener(SWT.Resize, listener);
            ScrollBar vBar = textWidget.getVerticalBar();
            if (vBar != null && !vBar.isDisposed()) {
                vBar.removeListener(SWT.Selection, listener);
            }
        }
        textWidget = null;
        listener = null;
    }

    /*
     * (non-Javadoc)
     * @see org.eclipse.ui.console.IConsolePageParticipant#activated()
     */
    public void activated() {
    }

    /*
     * (non-Javadoc)
     * @see org.eclipse.ui.console.IConsolePageParticipant#deactivated()
     */
    public void deactivated() {
    }

    private boolean isLastLineVisible(int topLineIndex) {
        int visibleLines = textWidget.getBounds().height / textWidget.getLineHeight();
        return (textWidget.getLineCount() - topLineIndex <= visibleLines);
    }

    /**
     * Console listener.
     */
    private final class ConsoleListener implements Listener {
        private IOConsoleViewer viewer;
        private IToolBarManager toolBarManager;
        private IAction scrollLockAction;
        int lastIndex = textWidget.getTopIndex();

        /**
         * @param viewer
         * @param toolBarManager
         * @param scrollLockAction
         */
        private ConsoleListener(IOConsoleViewer viewer, IToolBarManager toolBarManager, IAction scrollLockAction) {
            this.viewer = viewer;
            this.toolBarManager = toolBarManager;
            this.scrollLockAction = scrollLockAction;
        }

        public void handleEvent(Event event) {
            if (textWidget.isDisposed()) {
                return;
            }
            int index = textWidget.getTopIndex();
            if (index != lastIndex) {
                lastIndex = index;
                if (isLastLineVisible(index)) {
                    // The user scrolled to the bottom, so we re-set the auto-scroll to its original value.
                    viewer.setAutoScroll(scrollActionEnabled);
                    if (scrollLockAction != null) {
                        scrollLockAction.setChecked(!scrollActionEnabled);
                        toolBarManager.update(true);
                    }
                } else {
                    // The user scrolled up, so we turn off the auto-scrolling.
                    viewer.setAutoScroll(false);
                    if (scrollLockAction != null) {
                        scrollLockAction.setChecked(true);
                        toolBarManager.update(true);
                    }
                }
            }
        }
    }
}