ISpoutWaitStrategy.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.apache.storm.spout;

import java.util.Map;

/**
 * The strategy a spout needs to use when its waiting. Waiting is
 * triggered in one of two conditions:
 * <p>
 * 1. nextTuple emits no tuples
 * 2. The spout has hit maxSpoutPending and can't emit any more tuples
 * <p>
 * The default strategy sleeps for one millisecond.
 */
public interface ISpoutWaitStrategy {
  @SuppressWarnings("rawtypes")
  void prepare(Map conf);

  void emptyEmit(long streak);
}