/*
* Copyright (C) 2015 Red Hat, Inc. and/or its affiliates.
*
* 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.jboss.errai.databinding.client;
/**
* A partial implementation of {@link PropertyChangeUnsubscribeHandle} that only
* allows {@link PropertyChangeUnsubscribeHandle#unsubscribe()} to be called
* once.
*
* @author Max Barkley <mbarkley@redhat.com>
*/
public abstract class OneTimeUnsubscribeHandle implements PropertyChangeUnsubscribeHandle {
private boolean unsubscribed = false;
@Override
public void unsubscribe() {
if (unsubscribed) {
throw new RuntimeException("Can only call unsubscribe once.");
} else {
try {
doUnsubscribe();
} finally {
unsubscribed = true;
}
}
}
/**
* This method is guaranteed to only be called the first time
* {@link OneTimeUnsubscribeHandle#unsubscribe()} is called.
*
* @see PropertyChangeUnsubscribeHandle#unsubscribe()
*/
public abstract void doUnsubscribe();
}