Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ package org.apache.axiom.attachments; import javax.activation.FileDataSource; import java.io.File; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; public class CachedFileDataSource extends FileDataSource { String contentType = null; protected static Log log = LogFactory.getLog(CachedFileDataSource.class); // The AttachmentCacheMonitor is used to delete expired copies of attachment files. private static AttachmentCacheMonitor acm = AttachmentCacheMonitor.getAttachmentCacheMonitor(); // Represents the absolute pathname of cached attachment file private String cachedFileName = null; public CachedFileDataSource(File arg0) { super(arg0); if (log.isDebugEnabled()) { log.debug("Enter CachedFileDataSource ctor"); } if (arg0 != null) { try { cachedFileName = arg0.getCanonicalPath(); } catch (java.io.IOException e) { log.error("IOException caught: " + e); } } if (cachedFileName != null) { if (log.isDebugEnabled()) { log.debug("Cached file: " + cachedFileName); log.debug("Registering the file with AttachmentCacheMonitor and also marked it as being accessed"); } // Tell the monitor that the file is being accessed. acm.access(cachedFileName); // Register the file with the AttachmentCacheMonitor acm.register(cachedFileName); } } public String getContentType() { if (this.contentType != null) { return contentType; } else { return super.getContentType(); } } public void setContentType(String contentType) { this.contentType = contentType; } }