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.api.management.ManagedResource;
025 import org.apache.camel.api.management.mbean.ManagedResourceEndpointMBean;
026 import org.apache.camel.converter.IOConverter;
027 import org.apache.camel.impl.ProcessorEndpoint;
028 import org.apache.camel.util.IOHelper;
029 import org.apache.camel.util.ResourceHelper;
030 import org.slf4j.Logger;
031 import org.slf4j.LoggerFactory;
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 @ManagedResource(description = "Managed ResourceEndpoint")
038 public abstract class ResourceEndpoint extends ProcessorEndpoint implements ManagedResourceEndpointMBean {
039 protected final transient Logger log = LoggerFactory.getLogger(getClass());
040 private String resourceUri;
041 private boolean contentCache;
042 private volatile byte[] buffer;
043
044 public ResourceEndpoint() {
045 }
046
047 public ResourceEndpoint(String endpointUri, Component component, String resourceUri) {
048 super(endpointUri, component);
049 this.resourceUri = resourceUri;
050 }
051
052 /**
053 * Gets the resource as an input stream considering the cache flag as well.
054 * <p/>
055 * If cache is enabled then the resource content is cached in an internal buffer and this content is
056 * returned to avoid loading the resource over and over again.
057 *
058 * @return the input stream
059 * @throws IOException is thrown if error loading the content of the resource to the local cache buffer
060 */
061 public InputStream getResourceAsInputStream() throws IOException {
062 // try to get the resource input stream
063 InputStream is;
064 if (isContentCache()) {
065 synchronized (this) {
066 if (buffer == null) {
067 log.debug("Reading resource: {} into the content cache", resourceUri);
068 is = getResourceAsInputStreamWithoutCache();
069 buffer = IOConverter.toBytes(is);
070 IOHelper.close(is, resourceUri, log);
071 }
072 }
073 log.debug("Using resource: {} from the content cache", resourceUri);
074 return new ByteArrayInputStream(buffer);
075 }
076
077 return getResourceAsInputStreamWithoutCache();
078 }
079
080 protected InputStream getResourceAsInputStreamWithoutCache() throws IOException {
081 return loadResource(resourceUri);
082 }
083
084 /**
085 * Loads the given resource.
086 *
087 * @param uri uri of the resource.
088 * @return the loaded resource
089 * @throws IOException is thrown if resource is not found or cannot be loaded
090 */
091 protected InputStream loadResource(String uri) throws IOException {
092 return ResourceHelper.resolveMandatoryResourceAsInputStream(getCamelContext().getClassResolver(), uri);
093 }
094
095 public boolean isContentCache() {
096 return contentCache;
097 }
098
099 public void clearContentCache() {
100 log.debug("Clearing resource: {} from the content cache", resourceUri);
101 buffer = null;
102 }
103
104 /**
105 * Sets whether to use resource content cache or not - default is <tt>false</tt>.
106 *
107 * @see #getResourceAsInputStream()
108 */
109 public void setContentCache(boolean contentCache) {
110 this.contentCache = contentCache;
111 }
112
113 public String getResourceUri() {
114 return resourceUri;
115 }
116
117 public void setResourceUri(String resourceUri) {
118 this.resourceUri = resourceUri;
119 }
120 }