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'databene commons' is an open source Java library by Volker Bergmann. It provides extensions to the Java core library by utility classes, abstract concepts and concrete implementations.

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/*
 * Copyright (C) 2004-2015 Volker Bergmann ([email protected]).
 * All rights reserved.
 *
 * 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 org.databene.commons.ui.swing.delegate;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.File;

import org.databene.commons.BeanUtil;
import org.databene.commons.NullSafeComparator;
import org.databene.commons.bean.ObservableBean;
import org.databene.commons.ui.FileOperation;
import org.databene.commons.ui.FileTypeSupport;
import org.databene.commons.ui.swing.FileField;

/**
 * {@link FileField} implementation that serves as delegate of a property of a JavaBean object.
 * Created at 30.11.2008 00:22:14
 * @since 0.5.13
 * @author Volker Bergmann
 */
public class PropertyFileField extends FileField {
	
	// attributes ------------------------------------------------------------------------------------------------------
	
	private static final long serialVersionUID = -3970525222511845399L;
	
	private Object bean;
	private String propertyName;

	boolean locked;
	
	// constructors ----------------------------------------------------------------------------------------------------
	
	public PropertyFileField(Object bean, String propertyName, int length, FileTypeSupport typeSupport, FileOperation operation) {
		super(length, null, typeSupport, operation);
		init(bean, propertyName);
	}

	private void init(Object bean, String propertyName) {
		this.bean = bean;
		this.propertyName = propertyName;
		this.locked = true;
		refresh();
		Listener listener = new Listener();
		if (bean instanceof ObservableBean)
			((ObservableBean) bean).addPropertyChangeListener(propertyName, listener);
		this.addActionListener(listener);
		this.locked = false;
		File value = (File) BeanUtil.getPropertyValue(bean, propertyName);
		if (value != null)
			setFile(value);
	}
	
	// event handlers --------------------------------------------------------------------------------------------------

	/**
	 * reads the current property value and writes it to the file field.
	 */
	void refresh() {
		if (!locked) {
			locked = true;
			Object propertyValue = BeanUtil.getPropertyValue(bean, propertyName);
			File file = (File) propertyValue;
			if (!NullSafeComparator.equals(getFile(), file))
				setFile(file);
			locked = false;
		}
	}
	
	/**
	 * writes the current file field content to the property.
	 */
	void update() {
		if (!locked) {
			locked = true;
			File file = getFile();
			if (!NullSafeComparator.equals(file, BeanUtil.getPropertyValue(bean, propertyName)))
				BeanUtil.setPropertyValue(bean, propertyName, file);
			locked = false;
		}
	}
	
	class Listener implements PropertyChangeListener, ActionListener {

		@Override
		public void propertyChange(PropertyChangeEvent evt) {
			refresh();
		}

		@Override
		public void actionPerformed(ActionEvent evt) {
			update();
		}

	}
}