001/* 002 * Copyright 2006-2018 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 */ 016package org.springframework.batch.core.step.tasklet; 017 018import org.springframework.batch.core.StepContribution; 019import org.springframework.batch.core.scope.context.ChunkContext; 020import org.springframework.batch.repeat.RepeatStatus; 021import org.springframework.lang.Nullable; 022 023/** 024 * Strategy for processing in a step. 025 * 026 * @author Dave Syer 027 * @author Mahmoud Ben Hassine 028 * 029 */ 030public interface Tasklet { 031 032 /** 033 * Given the current context in the form of a step contribution, do whatever 034 * is necessary to process this unit inside a transaction. Implementations 035 * return {@link RepeatStatus#FINISHED} if finished. If not they return 036 * {@link RepeatStatus#CONTINUABLE}. On failure throws an exception. 037 * 038 * @param contribution mutable state to be passed back to update the current 039 * step execution 040 * @param chunkContext attributes shared between invocations but not between 041 * restarts 042 * @return an {@link RepeatStatus} indicating whether processing is 043 * continuable. Returning {@code null} is interpreted as {@link RepeatStatus#FINISHED} 044 * 045 * @throws Exception thrown if error occurs during execution. 046 */ 047 @Nullable 048 RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws Exception; 049 050}