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 storm.trident.operation;
  
  import storm.trident.tuple.TridentTuple;
  
  import java.util.Map;
  
  /**
   * Filters take in a tuple as input and decide whether or not to keep that tuple or not.
   *
   * If the `isKeep()` method of a Filter returns `false` for a tuple, that tuple will be filtered out of the Stream
   *
   *
   * ### Configuration
   * If your `Filter` implementation has configuration requirements, you will typically want to extend
   * {@link org.apache.storm.trident.operation.BaseFilter} and override the
   * {@link org.apache.storm.trident.operation.Operation#prepare(Map, TridentOperationContext)} method to perform your custom
   * initialization.
  
   *
   * @see org.apache.storm.trident.Stream
   */
  public interface Filter extends EachOperation {
  
      /**
       * Determines if a tuple should be filtered out of a stream
       *
       * @param tuple the tuple being evaluated
       * @return `false` to drop the tuple, `true` to keep the tuple
       */
      boolean isKeep(TridentTuple tuple);
  }
  