taverna-ui/src/main/java/org/apache/taverna/lang/ui/tabselector/ScrollController.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.taverna.lang.ui.tabselector;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JComponent;

/**
 * Controls tab scrolling when there is not enough space to show all the tabs.
 *
 * @author David Withers
 */
public class ScrollController {

	private int position;
	private final JButton scrollLeft;
	private final JButton scrollRight;

	public ScrollController(final JComponent component) {
		scrollLeft = new JButton("<");
		scrollRight = new JButton(">");
		scrollLeft.setOpaque(true);
		scrollRight.setOpaque(true);
		scrollLeft.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				increment();
				component.doLayout();
			}
		});
		scrollRight.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				decrement();
				component.doLayout();
			}
		});
	}

	public JButton getScrollLeft() {
		return scrollLeft;
	}

	public JButton getScrollRight() {
		return scrollRight;
	}

	public int getPosition() {
		return position;
	}

	public void reset() {
		position = 0;
	}

	public void increment() {
		position++;
	}

	public void decrement() {
		position--;
	}

}