001 /* 002 * Copyright 1999-2001,2004 The Apache Software Foundation. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017 package org.apache.commons.workflow; 018 019 020 /** 021 * <p>A <strong>Step</strong> represents a single executable action that 022 * can occur during the completion of an Activity. The dynamic execution 023 * of the implementation of this Step happens within the <code>execute()</code> 024 * method -- everything else about a Step is part of its static definition, 025 * which is shared among all users of the owning Activity.</p> 026 * 027 * @version $Revision: 155475 $ $Date: 2005-02-26 13:31:11 +0000 (Sat, 26 Feb 2005) $ 028 * @author Craig R. McClanahan 029 */ 030 031 public interface Step { 032 033 034 // ------------------------------------------------------------- Properties 035 036 037 /** 038 * Return the unique identifier (within this Activity) of this Step. 039 */ 040 public String getId(); 041 042 043 /** 044 * Set the unique identifier (within this Activity) of this Step. 045 * 046 * @param id The new unique identifier 047 */ 048 public void setId(String id); 049 050 051 /** 052 * Return the next Step in our associated Activity or Block. 053 */ 054 public Step getNextStep(); 055 056 057 /** 058 * Set the next Step in our associated Activity or Block. 059 * 060 * @param nextStep The new next Step 061 */ 062 public void setNextStep(Step nextStep); 063 064 065 /** 066 * Return the Activity or Block that owns this Step. 067 */ 068 public Owner getOwner(); 069 070 071 /** 072 * Set the Activity or Block that owns this Step. 073 * 074 * @param owner The new owning Activity or Block 075 */ 076 public void setOwner(Owner owner); 077 078 079 /** 080 * Return the previous Step in our associated Activity or Block. 081 */ 082 public Step getPreviousStep(); 083 084 085 /** 086 * Set the previous Step in our associated Activity or Block. 087 * 088 * @param previousStep The new previous Step 089 */ 090 public void setPreviousStep(Step previousStep); 091 092 093 // --------------------------------------------------------- Public Methods 094 095 096 /** 097 * Perform the executable actions related to this Step, in the context of 098 * the specified Context. 099 * 100 * @param context The Context that is tracking our execution state 101 * 102 * @exception StepException if a processing error has occurred 103 */ 104 public void execute(Context context) throws StepException; 105 106 107 }