001package org.apache.commons.jcs.utils.access; 002 003/* 004 * Licensed to the Apache Software Foundation (ASF) under one 005 * or more contributor license agreements. See the NOTICE file 006 * distributed with this work for additional information 007 * regarding copyright ownership. The ASF licenses this file 008 * to you under the Apache License, Version 2.0 (the 009 * "License"); you may not use this file except in compliance 010 * with the License. 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, 015 * software distributed under the License is distributed on an 016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 017 * KIND, either express or implied. See the License for the 018 * specific language governing permissions and limitations 019 * under the License. 020 */ 021 022/** 023 * Interface for doing a piece of work which is expected to be cached. This is 024 * meant to be used in conjunction with JCSWorker. 025 * <p> 026 * Implement doWork() to return the work being done. isFinished() should return 027 * false until setFinished(true) is called, after which time it should return 028 * true. 029 * <p> 030 * @author tsavo 031 */ 032public interface JCSWorkerHelper<V> 033{ 034 /** 035 * Tells us whether or not the work has been completed. This will be called 036 * automatically by JCSWorker. You should not call it yourself. 037 * <p> 038 * @return True if the work has already been done, otherwise false. 039 */ 040 boolean isFinished(); 041 042 /** 043 * Sets whether or not the work has been done. 044 * <p> 045 * @param isFinished 046 * True if the work has already been done, otherwise false. 047 */ 048 void setFinished( boolean isFinished ); 049 050 /** 051 * The method to implement to do the work that should be cached. JCSWorker 052 * will call this itself! You should not call this directly. 053 * <p> 054 * @return The result of doing the work to be cached. 055 * @throws Exception 056 * If anything goes wrong while doing the work, an Exception 057 * should be thrown. 058 */ 059 V doWork() throws Exception; 060}