001/* 002 * Copyright (c) 2016-2017 Chris K Wensel <chris@wensel.net>. 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 021package cascading.tap; 022 023import java.util.Collection; 024import java.util.Iterator; 025import java.util.Set; 026 027import cascading.util.Util; 028 029/** 030 * Helper utilities for {@link CompositeTap} instances. 031 */ 032public class CompositeTaps 033 { 034 private CompositeTaps() 035 { 036 } 037 038 public static Collection<? extends Tap> unwindNarrow( Class<? extends Tap> type, Tap tap ) 039 { 040 return Util.narrowIdentitySet( type, unwind( tap ) ); 041 } 042 043 public static Collection<Tap> unwind( Tap tap ) 044 { 045 Set<Tap> taps = Util.createIdentitySet(); 046 047 addLeaves( tap, taps ); 048 049 return taps; 050 } 051 052 private static void addLeaves( Tap tap, Set<Tap> taps ) 053 { 054 if( tap instanceof CompositeTap ) 055 { 056 Iterator<? extends Tap> childTaps = ( (CompositeTap<? extends Tap>) tap ).getChildTaps(); 057 058 while( childTaps.hasNext() ) 059 addLeaves( childTaps.next(), taps ); 060 } 061 else 062 { 063 taps.add( tap ); 064 } 065 } 066 }