/*
* Copyright (c) 2005-2016 Vincent Vandenschrick. All rights reserved.
*
* This file is part of the Jspresso framework.
*
* Jspresso 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 3 of the License, or
* (at your option) any later version.
*
* Jspresso 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 Jspresso. If not, see <http://www.gnu.org/licenses/>.
*/
package org.jspresso.framework.util.gate;
/**
* A simple gate that opens whenever its model is not empty.
*
* @author Vincent Vandenschrick
* @internal
*/
public class ModelTrackingGate extends AbstractModelGate {
/**
* {@code INSTANCE} is a singleton instance of a gate whose state depends
* on the underlying action model (null => closed, not null => open).
*/
public static final ModelTrackingGate INSTANCE = new ModelTrackingGate();
private static final Object START_MODEL = new Object();
/**
* Constructs a new {@code ModelTrackingGate} instance.
*/
public ModelTrackingGate() {
setCollectionBased(false);
setModel(START_MODEL);
}
/**
* Restores the default model.
* <p>
* {@inheritDoc}
*/
@Override
public ModelTrackingGate clone() {
ModelTrackingGate clonedGate = (ModelTrackingGate) super.clone();
clonedGate.setModel(START_MODEL);
return clonedGate;
}
/**
* Returns true whenever the model is not null.
* <p>
* {@inheritDoc}
*/
@Override
public boolean isOpen() {
return getModel() != null;
}
/**
* {@inheritDoc}
*/
@Override
public void setModel(Object model) {
boolean oldOpen = isOpen();
super.setModel(model);
firePropertyChange(OPEN_PROPERTY, oldOpen, isOpen());
}
}