/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.util.property;
import org.jboss.util.FieldInstance;
import org.jboss.util.NullArgumentException;
import org.jboss.util.Classes;
import org.jboss.util.Objects;
import org.jboss.util.CoercionException;
import org.jboss.util.ThrowableHandler;
/**
* Binds property values to class fields.
*
* @version <tt>$Revision: 1455 $</tt>
* @author <a href="mailto:jason@planet57.com">Jason Dillon</a>
*/
public class FieldBoundPropertyListener
extends BoundPropertyAdapter
{
/** Property name which we are bound to */
protected final String propertyName;
/** Field instance */
protected final FieldInstance fieldInstance;
/**
* Constructs a <tt>FieldBoundPropertyListener</tt>.
*
* @param instance Instance object.
* @param fieldName Field name.
* @param propertyName Property to bind to.
*
* @throws NullArgumentException Property name is <tt>null</tt>.
*/
public FieldBoundPropertyListener(final Object instance,
final String fieldName,
final String propertyName)
{
if (propertyName == null)
throw new NullArgumentException("propertyName");
// FieldInstance checks instance & fieldName
this.propertyName = propertyName;
try {
// construct field instance
fieldInstance = new FieldInstance(instance, fieldName);
try {
fieldInstance.getField().setAccessible(true);
}
catch (SecurityException e) {
ThrowableHandler.add(e);
}
// force the given class to load, so that any CoersionHelpers
// that are nested in it are loaded properly
Classes.forceLoad(fieldInstance.getField().getType());
}
catch (NoSuchFieldException e) {
throw new PropertyException(e);
}
}
/**
* Constructs a <tt>FieldBoundPropertyListener</tt>.
*
* <p>Field name is used for property name.
*
* @param instance Instance object.
* @param fieldName Field name.
*/
public FieldBoundPropertyListener(final Object instance,
final String fieldName)
{
this(instance, fieldName, fieldName);
}
/**
* Get the property name which this listener is bound to.
*
* @return Property name.
*/
public final String getPropertyName() {
return propertyName;
}
/**
* Filter the property value prior to coercing and binding to field.
*
* <p>Allows instance to filter values prior to object coercion and
* field binding.
*
* @param value Property value.
*/
public String filterValue(String value) {
return value;
}
/**
* Coerce and set specified value to field.
*
* @param value Field value.
*
* @throws PropertyException Failed to set field value.
*/
protected void setFieldValue(String value) {
try {
// filter property value
value = filterValue(value);
// coerce value to field type
Class type = fieldInstance.getField().getType();
Object coerced = Objects.coerce(value, type);
// bind value to field
fieldInstance.set(coerced);
}
catch (IllegalAccessException e) {
throw new PropertyException(e);
}
catch (CoercionException e) {
throw new PropertyException(e);
}
}
/**
* Notifies that a property has been added.
*
* @param event Property event.
*/
public void propertyAdded(final PropertyEvent event) {
setFieldValue(event.getPropertyValue());
}
/**
* Notifies that a property has changed
*
* @param event Property event
*/
public void propertyChanged(final PropertyEvent event) {
setFieldValue(event.getPropertyValue());
}
/**
* Notifies that this listener was bound to a property.
*
* @param map PropertyMap which contains property bound to.
*/
public void propertyBound(final PropertyMap map) {
// only set the field if the map contains the property already
if (map.containsProperty(propertyName)) {
setFieldValue(map.getProperty(propertyName));
}
}
}