001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018package org.apache.commons.configuration2.reloading; 019 020import org.apache.commons.configuration2.ex.ConfigurationRuntimeException; 021import org.apache.commons.configuration2.io.FileHandler; 022import org.apache.commons.configuration2.io.FileSystem; 023import org.apache.commons.logging.Log; 024import org.apache.commons.logging.LogFactory; 025import org.apache.commons.vfs2.FileObject; 026import org.apache.commons.vfs2.FileSystemException; 027import org.apache.commons.vfs2.FileSystemManager; 028import org.apache.commons.vfs2.VFS; 029 030/** 031 * <p> 032 * A file-based reloading strategy that uses <a 033 * href="http://commons.apache.org/vfs/">Commons VFS</a> to determine when a 034 * file was changed. 035 * </p> 036 * <p> 037 * This reloading strategy is very similar to 038 * {@link FileHandlerReloadingDetector}, except for the fact that it uses VFS 039 * and thus can deal with a variety of different configuration sources. 040 * </p> 041 * <p> 042 * This strategy only works with FileConfiguration instances. 043 * </p> 044 * 045 * @author <a 046 * href="http://commons.apache.org/configuration/team-list.html">Commons 047 * Configuration team</a> 048 * @version $Id: VFSFileHandlerReloadingDetector.java 1624601 2014-09-12 18:04:36Z oheger $ 049 * @since 1.7 050 */ 051public class VFSFileHandlerReloadingDetector extends FileHandlerReloadingDetector 052{ 053 /** Stores the logger.*/ 054 private final Log log = LogFactory.getLog(getClass()); 055 056 /** 057 * Creates a new instance of {@code VFSFileHandlerReloadingDetector} and 058 * initializes it with an empty {@code FileHandler} object. 059 */ 060 public VFSFileHandlerReloadingDetector() 061 { 062 super(); 063 } 064 065 /** 066 * Creates a new instance of {@code VFSFileHandlerReloadingDetector} and 067 * initializes it with the given {@code FileHandler} object and the given 068 * refresh delay. 069 * 070 * @param handler the {@code FileHandler} 071 * @param refreshDelay the refresh delay 072 */ 073 public VFSFileHandlerReloadingDetector(FileHandler handler, 074 long refreshDelay) 075 { 076 super(handler, refreshDelay); 077 } 078 079 /** 080 * Creates a new instance of {@code VFSFileHandlerReloadingDetector} and 081 * initializes it with the given {@code FileHandler} object. 082 * 083 * @param handler the {@code FileHandler} 084 */ 085 public VFSFileHandlerReloadingDetector(FileHandler handler) 086 { 087 super(handler); 088 } 089 090 /** 091 * {@inheritDoc} This implementation uses Commons VFS to obtain a 092 * {@code FileObject} and read the date of the last modification. 093 */ 094 @Override 095 protected long getLastModificationDate() 096 { 097 FileObject file = getFileObject(); 098 try 099 { 100 if (file == null || !file.exists()) 101 { 102 return 0; 103 } 104 105 return file.getContent().getLastModifiedTime(); 106 } 107 catch (FileSystemException ex) 108 { 109 log.error("Unable to get last modified time for" 110 + file.getName().getURI(), ex); 111 return 0; 112 } 113 } 114 115 /** 116 * Returns the file that is monitored by this strategy. Note that the return 117 * value can be <b>null </b> under some circumstances. 118 * 119 * @return the monitored file 120 */ 121 protected FileObject getFileObject() 122 { 123 if (!getFileHandler().isLocationDefined()) 124 { 125 return null; 126 } 127 128 try 129 { 130 FileSystemManager fsManager = VFS.getManager(); 131 String uri = resolveFileURI(); 132 if (uri == null) 133 { 134 throw new ConfigurationRuntimeException("Unable to determine file to monitor"); 135 } 136 return fsManager.resolveFile(uri); 137 } 138 catch (FileSystemException fse) 139 { 140 String msg = "Unable to monitor " + getFileHandler().getURL().toString(); 141 log.error(msg); 142 throw new ConfigurationRuntimeException(msg, fse); 143 } 144 } 145 146 /** 147 * Resolves the URI of the monitored file. 148 * 149 * @return the URI of the monitored file or <b>null</b> if it cannot be 150 * resolved 151 */ 152 protected String resolveFileURI() 153 { 154 FileSystem fs = getFileHandler().getFileSystem(); 155 String uri = 156 fs.getPath(null, getFileHandler().getURL(), getFileHandler() 157 .getBasePath(), getFileHandler().getFileName()); 158 return uri; 159 } 160}