001// Copyright 2013 The Apache Software Foundation 002// 003// Licensed under the Apache License, Version 2.0 (the "License"); 004// you may not use this file except in compliance with the License. 005// You may obtain a copy of the License at 006// 007// http://www.apache.org/licenses/LICENSE-2.0 008// 009// Unless required by applicable law or agreed to in writing, software 010// distributed under the License is distributed on an "AS IS" BASIS, 011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 012// See the License for the specific language governing permissions and 013// limitations under the License. 014 015package org.apache.tapestry5.internal.webresources; 016 017import org.apache.tapestry5.ioc.Resource; 018import org.apache.tapestry5.ioc.internal.util.CollectionFactory; 019import org.apache.tapestry5.services.assets.ResourceDependencies; 020 021import java.io.IOException; 022import java.util.Map; 023 024/** 025 * Manages a collection of Resources and can check to see if any resource's actual content has changed. 026 * 027 * @since 5.4 028 */ 029public class ContentChangeTracker implements ResourceDependencies 030{ 031 private final Map<Resource, Long> checksums = CollectionFactory.newMap(); 032 033 public void addDependency(Resource dependency) 034 { 035 long checksum = ResourceTransformUtils.toChecksum(dependency); 036 037 checksums.put(dependency, checksum); 038 } 039 040 /** 041 * Checks all resources tracked by this instance and returns true if any resource's content has changed. 042 * 043 * @return true if a change has occurred 044 */ 045 public boolean dirty() throws IOException 046 { 047 for (Map.Entry<Resource, Long> e : checksums.entrySet()) 048 { 049 long current = ResourceTransformUtils.toChecksum(e.getKey()); 050 051 if (current != e.getValue().longValue()) 052 { 053 return true; 054 } 055 } 056 057 return false; 058 } 059 060 061}