001/* 002 * Copyright 2006-2007 the original author or authors. 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 * https://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 017package org.springframework.batch.repeat; 018 019 020/** 021 * Interface for batch completion policies, to enable batch operations to 022 * strategise normal completion conditions. Stateful implementations of batch 023 * iterators should <em>only</em> update state using the update method. If you 024 * need custom behaviour consider extending an existing implementation or using 025 * the composite provided. 026 * 027 * @author Dave Syer 028 * 029 */ 030public interface CompletionPolicy { 031 032 /** 033 * Determine whether a batch is complete given the latest result from the 034 * callback. If this method returns true then 035 * {@link #isComplete(RepeatContext)} should also (but not necessarily vice 036 * versa, since the answer here depends on the result). 037 * 038 * @param context the current batch context. 039 * @param result the result of the latest batch item processing. 040 * 041 * @return true if the batch should terminate. 042 * 043 * @see #isComplete(RepeatContext) 044 */ 045 boolean isComplete(RepeatContext context, RepeatStatus result); 046 047 /** 048 * Allow policy to signal completion according to internal state, without 049 * having to wait for the callback to complete. 050 * 051 * @param context the current batch context. 052 * 053 * @return true if the batch should terminate. 054 */ 055 boolean isComplete(RepeatContext context); 056 057 /** 058 * Create a new context for the execution of a batch. N.B. implementations 059 * should <em>not</em> return the parent from this method - they must 060 * create a new context to meet the specific needs of the policy. The best 061 * way to do this might be to override an existing implementation and use 062 * the {@link RepeatContext} to store state in its attributes. 063 * 064 * @param parent the current context if one is already in progress. 065 * @return a context object that can be used by the implementation to store 066 * internal state for a batch. 067 */ 068 RepeatContext start(RepeatContext parent); 069 070 /** 071 * Give implementations the opportunity to update the state of the current 072 * batch. Will be called <em>once</em> per callback, after it has been 073 * launched, but not necessarily after it completes (if the batch is 074 * asynchronous). 075 * 076 * @param context the value returned by start. 077 */ 078 void update(RepeatContext context); 079 080}