au.gov.ga.earthsci.discovery.ui.TableViewerSelectionHelper.java Source code

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Here is the source code for au.gov.ga.earthsci.discovery.ui.TableViewerSelectionHelper.java

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/*******************************************************************************
 * Copyright 2013 Geoscience Australia
 * 
 * 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 au.gov.ga.earthsci.discovery.ui;

import org.eclipse.jface.viewers.ColumnViewer;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.jface.viewers.TableViewer;
import org.eclipse.jface.viewers.ViewerCell;
import org.eclipse.swt.events.MouseAdapter;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.graphics.Point;

/**
 * Class that provides listeners for a {@link ColumnViewer} that notify an
 * abstract method when an item in the viewer's control has been selected.
 * 
 * @author Michael de Hoog (michael.dehoog@ga.gov.au)
 */
public abstract class TableViewerSelectionHelper<T> {
    public TableViewerSelectionHelper(final TableViewer viewer, final Class<T> selectionType) {
        viewer.getControl().addMouseListener(new MouseAdapter() {
            @Override
            public void mouseDown(MouseEvent e) {
                ViewerCell cell = viewer.getCell(new Point(e.x, e.y));
                if (cell == null) {
                    viewer.setSelection(StructuredSelection.EMPTY);
                }
            }
        });

        viewer.getTable().addSelectionListener(new SelectionListener() {
            @Override
            public void widgetSelected(SelectionEvent e) {
                IStructuredSelection selection = (IStructuredSelection) viewer.getSelection();
                Object s = selection.getFirstElement();
                if (s == null) {
                    itemSelected(null);
                } else if (selectionType.isInstance(s)) {
                    T t = selectionType.cast(s);
                    itemSelected(t);
                }
            }

            @Override
            public void widgetDefaultSelected(SelectionEvent e) {
                IStructuredSelection selection = (IStructuredSelection) viewer.getSelection();
                Object s = selection.getFirstElement();
                if (selectionType.isInstance(s)) {
                    T t = selectionType.cast(s);
                    itemDefaultSelected(t);
                }
            }
        });
    }

    /**
     * Called when the given item is selected in the viewer.
     * 
     * @param selection
     *            Selected item
     */
    protected abstract void itemSelected(T selection);

    /**
     * Called when the given item is default selected in the viewer. This is a
     * strong selection, such as a double-click by the user's mouse or the
     * RETURN/ENTER key pressed.
     * 
     * @param selection
     *            Selected item
     */
    protected abstract void itemDefaultSelected(T selection);
}