001    /*
002     * Copyright (c) 2007-2014 Concurrent, Inc. All Rights Reserved.
003     *
004     * Project and contact information: http://www.cascading.org/
005     *
006     * This file is part of the Cascading project.
007     *
008     * Licensed under the Apache License, Version 2.0 (the "License");
009     * you may not use this file except in compliance with the License.
010     * You may obtain a copy of the License at
011     *
012     *     http://www.apache.org/licenses/LICENSE-2.0
013     *
014     * Unless required by applicable law or agreed to in writing, software
015     * distributed under the License is distributed on an "AS IS" BASIS,
016     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
017     * See the License for the specific language governing permissions and
018     * limitations under the License.
019     */
020    
021    package cascading.flow.stream;
022    
023    /**
024     *
025     */
026    public abstract class Gate<Incoming, Outgoing> extends Duct<Incoming, Outgoing>
027      {
028      protected Duct[] allPrevious;
029    
030      public Gate()
031        {
032        }
033    
034      @Override
035      public void bind( StreamGraph streamGraph )
036        {
037        super.bind( streamGraph ); // sets next
038    
039        allPrevious = getAllPreviousFor( streamGraph );
040        }
041    
042      /**
043       * the actual previous in this context, not necessarily the declared previous
044       *
045       * @param streamGraph of type StreamGraph
046       * @return of type Duct[]
047       */
048      protected Duct[] getAllPreviousFor( StreamGraph streamGraph )
049        {
050        return streamGraph.findAllPreviousFor( this );
051        }
052      }