Scheduler.java

/**
 * 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.model.util;

/**
 * A scheduler that can be used for scheduling a single task. The most common use case
 * is having a scheduler that backs off the more you call schedule.
 *
 * @author zdwang@google.com (David Wang)
 */
public interface Scheduler {

  /** Simple command that can be invoked */
  public interface Command {
    void execute();
  }

  /**
   * Resets the backoff time and resets the scheduled job.
   */
  void reset();

  /**
   * Schedules a task to be ran in the future. If a previous task was
   * scheduled, it's cancelled.
   *
   * @param task the task to schedule
   * @return true if the task was scheduled, or false if it was rejected
   */
  boolean schedule(Command task);
}