org.eclipse.mylyn.internal.tasks.ui.commands.GoToUnreadTaskHandler.java Source code

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Here is the source code for org.eclipse.mylyn.internal.tasks.ui.commands.GoToUnreadTaskHandler.java

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/*******************************************************************************
 * Copyright (c) 2004, 2008 Tasktop Technologies and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Tasktop Technologies - initial API and implementation
 *******************************************************************************/

package org.eclipse.mylyn.internal.tasks.ui.commands;

import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.jface.viewers.TreePath;
import org.eclipse.jface.viewers.TreeSelection;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
import org.eclipse.mylyn.internal.tasks.ui.util.TreeWalker;
import org.eclipse.mylyn.internal.tasks.ui.util.TreeWalker.Direction;
import org.eclipse.mylyn.internal.tasks.ui.util.TreeWalker.TreeVisitor;
import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
import org.eclipse.mylyn.tasks.core.IRepositoryElement;
import org.eclipse.mylyn.tasks.core.ITask;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeItem;

/**
 * @author Steffen Pingel
 */
public abstract class GoToUnreadTaskHandler extends AbstractTaskListViewHandler {

    public static final String ID_NEXT = "org.eclipse.mylyn.tasklist.actions.goToNextUnread"; //$NON-NLS-1$

    public static final String ID_PREVIOUS = "org.eclipse.mylyn.tasklist.actions.goToPreviousUnread"; //$NON-NLS-1$

    private Direction direction = Direction.DOWN;

    public Direction getDirection() {
        return direction;
    }

    private TreePath getUnreadItem(TreeViewer treeViewer, Tree tree) {
        TreeItem[] selection = tree.getSelection();
        TreeItem selectedItem = (selection.length > 0) ? selection[0] : null;

        TreeVisitor visitor = new TreeVisitor() {
            @Override
            public boolean visit(Object object) {
                if (object instanceof ITask) {
                    ITask task = (ITask) object;
                    if (TasksUiInternal.shouldShowIncoming(task)) { // task.getSynchronizationState().isIncoming()
                        return true;
                    }
                }
                return false;
            }
        };

        TreeWalker treeWalker = new TreeWalker(treeViewer);
        treeWalker.setDirection(direction);
        treeWalker.setExpandNodes(true);
        return treeWalker.walk(visitor, selectedItem);
    }

    @Override
    protected void execute(ExecutionEvent event, TaskListView taskListView, IRepositoryElement item) {
        TreeViewer treeViewer = taskListView.getViewer();
        Tree tree = treeViewer.getTree();

        // need to expand nodes to traverse the tree, disable redraw to avoid flickering
        TreePath treePath = null;
        try {
            tree.setRedraw(false);
            treePath = getUnreadItem(treeViewer, tree);
        } finally {
            tree.setRedraw(true);
        }

        if (treePath != null) {
            treeViewer.expandToLevel(treePath, 0);
            treeViewer.setSelection(new TreeSelection(treePath), true);
        }
    }

    public void setDirection(Direction direction) {
        this.direction = direction;
    }

    public static void execute(ExecutionEvent event, Direction direction) throws ExecutionException {
        GoToUnreadTaskHandler handler = new GoToUnreadTaskHandler() {
        };
        handler.setDirection(direction);
        handler.execute(event);
    }

    public static class GoToNextUnreadTaskHandler extends GoToUnreadTaskHandler {

        public GoToNextUnreadTaskHandler() {
            setDirection(Direction.DOWN);
        }

    }

    public static class GoToPreviousUnreadTaskHandler extends GoToUnreadTaskHandler {

        public GoToPreviousUnreadTaskHandler() {
            setDirection(Direction.UP);
        }

    }

}