rabbit.ui.internal.viewers.Viewers.java Source code

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Here is the source code for rabbit.ui.internal.viewers.Viewers.java

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/*
 * Copyright 2010 The Rabbit Eclipse Plug-in Project
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package rabbit.ui.internal.viewers;

import org.eclipse.jface.layout.GridLayoutFactory;
import org.eclipse.jface.viewers.DoubleClickEvent;
import org.eclipse.jface.viewers.IDoubleClickListener;
import org.eclipse.jface.viewers.ITreeSelection;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.jface.viewers.TreePath;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.jface.viewers.TreeViewerColumn;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.MouseAdapter;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.ui.dialogs.FilteredTree;
import org.eclipse.ui.dialogs.PatternFilter;

/**
 * Utility methods for working with viewers.
 */
public final class Viewers {

    /**
     * Creates a new, configured {@link FilteredTree}.
     * @param parent the parent composite.
     * @param filter the filter for the tree.
     * @return a {@link FilteredTree}.
     */
    public static FilteredTree newFilteredTree(Composite parent, PatternFilter filter) {
        GridLayoutFactory.fillDefaults().margins(0, 0).applyTo(parent);

        int style = SWT.VIRTUAL | SWT.V_SCROLL | SWT.H_SCROLL;
        @SuppressWarnings("deprecation")
        // Need this for Eclipse 3.4:
        FilteredTree tree = new FilteredTree(parent, style, filter);
        tree.setBackground(parent.getBackground());
        tree.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));

        // Make it look a bit nicer for us:
        GridLayout layout = (GridLayout) tree.getLayout();
        layout.verticalSpacing = 0;
        layout = (GridLayout) tree.getFilterControl().getParent().getLayout();
        layout.marginHeight = 5;
        layout.marginWidth = 5;

        TreeViewer viewer = tree.getViewer();
        viewer.setUseHashlookup(true);
        viewer.getTree().setHeaderVisible(true);
        expandOnDoubleClick(viewer);
        clearEmptySelection(viewer);

        return tree;
    }

    /**
     * Creates a new {@link TreeViewerColumn}.
     * @param viewer the parent viewer.
     * @param style the style of the column.
     * @param text the text of the column.
     * @param width the width of the column
     * @return a column.
     */
    public static TreeViewerColumn newTreeViewerColumn(TreeViewer viewer, int style, String text, int width) {
        TreeViewerColumn column = new TreeViewerColumn(viewer, style);
        column.getColumn().setResizable(true);
        column.getColumn().setMoveable(true);
        column.getColumn().setWidth(width);
        column.getColumn().setText(text);
        return column;
    }

    /**
     * Refreshes the given viewer.
     */
    public static void refresh(TreeViewer viewer) {
        viewer.getTree().setRedraw(false);
        viewer.refresh();
        viewer.getTree().setRedraw(true);
    }

    /**
     * Gets the current input of the viewer and calls
     * {@link TreeViewer#setInput(Object)} on it.
     */
    public static void resetInput(TreeViewer viewer) {
        TreePath[] paths = viewer.getExpandedTreePaths();
        viewer.getTree().setRedraw(false);
        viewer.setInput(viewer.getInput());
        viewer.setExpandedTreePaths(paths);
        viewer.getTree().setRedraw(true);
    }

    /**
     * Clears the selection when user clicks on empty area.
     */
    private static void clearEmptySelection(final TreeViewer viewer) {
        viewer.getTree().addMouseListener(new MouseAdapter() {
            @Override
            public void mouseUp(MouseEvent e) {
                super.mouseDown(e);
                if (viewer.getTree().getItem(new Point(e.x, e.y)) == null) {
                    viewer.setSelection(StructuredSelection.EMPTY);
                }
            }
        });
    }

    /**
     * Configures the given viewer to expand/collapse an tree branch when double
     * clicked on the item.
     */
    private static void expandOnDoubleClick(final TreeViewer viewer) {
        viewer.addDoubleClickListener(new IDoubleClickListener() {
            @Override
            public void doubleClick(DoubleClickEvent e) {
                if (!(e.getSelection() instanceof ITreeSelection)) {
                    return;
                }

                ITreeSelection selection = (ITreeSelection) e.getSelection();
                TreePath[] paths = selection.getPaths();
                if (paths != null && paths.length > 0) {
                    viewer.setExpandedState(paths[0], !viewer.getExpandedState(paths[0]));
                }
            }
        });
    }

    private Viewers() {
    }
}