SelectionTableColumnClickListener.java

/*
 * Copyright 2009-2012 Amazon Technologies, Inc.
 * 
 * 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://aws.amazon.com/apache2.0
 * 
 * This file 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 com.amazonaws.eclipse.ec2.ui;

import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.widgets.TreeColumn;

/**
 * SelectionListener for SelectionTable columns to control sorting for the
 * associated comparator.
 */
public class SelectionTableColumnClickListener extends SelectionAdapter {
	/** The index of the column associated with this listener */
	private final int columnIndex;
	
	/** The comparator controlling sorting on the associated table */
	private final SelectionTableComparator comparator;

	/** The viewer associated with this column click listener */
	private final TreeViewer viewer;

	/**
	 * Creates a new SelectionTableColumnClickListener associated with the
	 * specified column and comparator.
	 * 
	 * @param columnIndex
	 *            The index of the column associated with this listener.
	 * @param comparator
	 *            The comparator that controls sorting on the associated
	 *            selection table.
	 */
	public SelectionTableColumnClickListener(int columnIndex, TreeViewer viewer, SelectionTableComparator comparator) {
		this.columnIndex = columnIndex;
		this.viewer = viewer;
		this.comparator = comparator;
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.swt.events.SelectionAdapter#widgetSelected(org.eclipse.swt.events.SelectionEvent)
	 */
	@Override
	public void widgetSelected(SelectionEvent e) {
		TreeColumn treeColumn = (TreeColumn)e.getSource();
		viewer.getTree().setSortColumn(treeColumn);

		// If we're already sorting in this column and the user
		// clicks on it, we want to reverse the sort direction.
		if (comparator.getColumn() == columnIndex) {
			comparator.reverseDirection();
		}
		comparator.setColumn(columnIndex);

		viewer.getTree().setSortDirection(comparator.getDirection());
		viewer.refresh();
	}
}