001 /* 002 * Copyright (c) 2007-2015 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; 022 023 import java.io.Serializable; 024 import java.util.Set; 025 026 import cascading.flow.planner.Scope; 027 import cascading.property.ConfigDef; 028 import cascading.tuple.Fields; 029 030 /** 031 * Interface FlowElement is a utility interface used internally to simplify DAG management. It is not intended 032 * for users to interact with these methods directly. 033 */ 034 public interface FlowElement extends Serializable 035 { 036 /** 037 * Method outgoingScopeFor returns the Scope this FlowElement hands off to the next FlowElement. 038 * 039 * @param incomingScopes of type Set<Scope> 040 * @return Scope 041 */ 042 Scope outgoingScopeFor( Set<Scope> incomingScopes ); 043 044 /** 045 * Method resolveIncomingOperationArgumentFields returns the Fields outgoing from the previous FlowElement that 046 * are consumable by this FlowElement when preparing Operation arguments. 047 * 048 * @param incomingScope of type Scope 049 * @return Fields 050 */ 051 Fields resolveIncomingOperationArgumentFields( Scope incomingScope ); 052 053 /** 054 * Method resolveIncomingOperationPassThroughFields returns the Fields outgoing from the previous FlowElement that 055 * are consumable by this FlowElement when preparing the Pipe outgoing tuple. 056 * 057 * @param incomingScope of type Scope 058 * @return Fields 059 */ 060 Fields resolveIncomingOperationPassThroughFields( Scope incomingScope ); 061 062 boolean isEquivalentTo( FlowElement element ); 063 064 ConfigDef getStepConfigDef(); 065 066 boolean hasStepConfigDef(); 067 068 ConfigDef getConfigDef(); 069 070 boolean hasConfigDef(); 071 }