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 package org.apache.camel.component;
018
019 import java.io.ByteArrayInputStream;
020 import java.io.IOException;
021 import java.io.InputStream;
022
023 import org.apache.camel.Component;
024 import org.apache.camel.Processor;
025 import org.apache.camel.converter.IOConverter;
026 import org.apache.camel.impl.ProcessorEndpoint;
027 import org.apache.commons.logging.Log;
028 import org.apache.commons.logging.LogFactory;
029 import org.springframework.core.io.DefaultResourceLoader;
030 import org.springframework.core.io.Resource;
031 import org.springframework.core.io.ResourceLoader;
032
033 /**
034 * A useful base class for endpoints which depend on a resource
035 * such as things like Velocity or XQuery based components.
036 *
037 * @version $Revision: 736637 $
038 */
039 public abstract class ResourceBasedEndpoint extends ProcessorEndpoint {
040 protected final transient Log log = LogFactory.getLog(getClass());
041 private final String resourceUri;
042 private ResourceLoader resourceLoader = new DefaultResourceLoader();
043 private Resource resource;
044 private boolean contentCache;
045 private byte[] buffer;
046
047 public ResourceBasedEndpoint(String endpointUri, Component component, String resourceUri, Processor processor) {
048 super(endpointUri, component, processor);
049 this.resourceUri = resourceUri;
050 }
051
052 protected ResourceBasedEndpoint(String endpointUri, Processor processor, String resourceUri) {
053 super(endpointUri, processor);
054 this.resourceUri = resourceUri;
055 }
056
057 public Resource getResource() {
058 if (resource == null) {
059 if (log.isDebugEnabled()) {
060 log.debug("Loading resource: " + resourceUri + " using: " + getResourceLoader());
061 }
062 resource = getResourceLoader().getResource(resourceUri);
063 if (resource == null) {
064 throw new IllegalArgumentException("Could not find resource for URI: " + resourceUri + " using: " + getResourceLoader());
065 }
066 }
067 return resource;
068 }
069
070 public boolean isContentCache() {
071 return contentCache;
072 }
073
074 /**
075 * Sets wether to use resource content cache or not - default is <tt>false</tt>.
076 *
077 * @see #getResourceAsInputStream()
078 */
079 public void setContentCache(boolean contentCache) {
080 this.contentCache = contentCache;
081 }
082
083 /**
084 * Gets the resource as an input stream considering the cache flag as well.
085 * <p/>
086 * If cache is enabled then the resource content is cached in an internal buffer and this content is
087 * returned to avoid loading the resource over and over again.
088 *
089 * @return the input stream
090 * @throws IOException is thrown if error loading the content of the resource to the local cache buffer
091 */
092 public InputStream getResourceAsInputStream() throws IOException {
093 if (resource == null) {
094 // get the resource if not already done
095 resource = getResource();
096 }
097 if (contentCache) {
098 synchronized (resource) {
099 if (buffer == null) {
100 if (log.isDebugEnabled()) {
101 log.debug("Reading resource: " + resourceUri + " into the content cache");
102 }
103 buffer = IOConverter.toBytes(resource.getInputStream());
104 }
105 }
106 if (log.isDebugEnabled()) {
107 log.debug("Using resource: " + resourceUri + " from the content cache");
108 }
109 return new ByteArrayInputStream(buffer);
110 }
111 return resource.getInputStream();
112 }
113
114 public ResourceLoader getResourceLoader() {
115 return resourceLoader;
116 }
117
118 public void setResourceLoader(ResourceLoader resourceLoader) {
119 this.resourceLoader = resourceLoader;
120 }
121
122 public String getResourceUri() {
123 return resourceUri;
124 }
125 }