content: /*
   * 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 com.alibaba.jstorm.window;
  
  /**
   * A {@link Trigger} that fires once the count of elements in a pane reaches the given count.
   */
  public class CountTrigger<T> extends Trigger<T> {
      private static final long serialVersionUID = 1L;
  
      private final long maxCount;
      private long count;
  
      private CountTrigger(long maxCount) {
          this.maxCount = maxCount;
      }
  
      @Override
      public TriggerResult onElement(Object element, long timestamp, TimeWindow window, TriggerContext ctx) {
          count++;
          if (count >= maxCount) {
              count = 0;
              return TriggerResult.FIRE;
          }
          return TriggerResult.CONTINUE;
      }
  
      @Override
      public String toString() {
          return "CountTrigger(" + maxCount + ")";
      }
  
      /**
       * Creates a trigger that fires once the number of elements in a pane reaches the given count.
       *
       * @param maxCount The count of elements at which to fire.
       */
      public static <T> CountTrigger<T> of(long maxCount) {
          return new CountTrigger<>(maxCount);
      }
  }
  