/**
* 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.waveprotocol.wave.client.scheduler;
import com.google.gwt.user.client.Command;
/**
* A command that will be notified if it isn't going to be execute()d.
*
*/
public interface CancellableCommand extends Command {
/**
* A do-nothing instance.
*/
public static final CancellableCommand NO_OP = new CancellableCommand() {
@Override
public void execute() {}
@Override
public void onCancelled() {}
};
/**
* Indicate to this command that it will never be execute()d.
*/
void onCancelled();
}