/**
* 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.camel.component.velocity;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringWriter;
import java.util.Map;
import org.apache.camel.Exchange;
import org.apache.camel.ExchangePattern;
import org.apache.camel.Message;
import org.apache.camel.component.ResourceBasedEndpoint;
import org.apache.camel.util.ExchangeHelper;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.Velocity;
import org.apache.velocity.app.VelocityEngine;
import org.apache.velocity.context.Context;
import org.apache.velocity.runtime.log.SimpleLog4JLogSystem;
import org.springframework.core.io.Resource;
/**
* @version $Revision: 736047 $
*/
public class VelocityEndpoint extends ResourceBasedEndpoint {
private final VelocityComponent component;
private VelocityEngine velocityEngine;
private boolean loaderCache = true;
private String encoding;
public VelocityEndpoint(String uri, VelocityComponent component, String resourceUri, Map parameters) {
super(uri, component, resourceUri, null);
this.component = component;
}
@Override
public boolean isSingleton() {
return true;
}
@Override
public ExchangePattern getExchangePattern() {
return ExchangePattern.InOut;
}
private VelocityEngine getVelocityEngine() throws Exception {
if (velocityEngine == null) {
velocityEngine = component.getVelocityEngine();
velocityEngine.setProperty(Velocity.FILE_RESOURCE_LOADER_CACHE, isLoaderCache() ? Boolean.TRUE : Boolean.FALSE);
velocityEngine.setProperty(Velocity.RUNTIME_LOG_LOGSYSTEM_CLASS, SimpleLog4JLogSystem.class.getName());
velocityEngine.setProperty("runtime.log.logsystem.log4j.category", VelocityEndpoint.class.getName());
velocityEngine.init();
}
return velocityEngine;
}
public void setVelocityEngine(VelocityEngine velocityEngine) {
this.velocityEngine = velocityEngine;
}
public boolean isLoaderCache() {
return loaderCache;
}
/**
* Enables / disables the velocity resource loader cache which is enabled by default
*
* @param loaderCache a flag to enable/disable the cache
*/
public void setLoaderCache(boolean loaderCache) {
this.loaderCache = loaderCache;
}
public void setEncoding(String encoding) {
this.encoding = encoding;
}
public String getEncoding() {
return encoding;
}
@SuppressWarnings("unchecked")
@Override
protected void onExchange(Exchange exchange) throws Exception {
Resource resource = getResource();
// getResourceAsInputStream also considers the content cache
Reader reader = encoding != null ? new InputStreamReader(getResourceAsInputStream(), encoding) : new InputStreamReader(getResourceAsInputStream());
StringWriter buffer = new StringWriter();
String logTag = getClass().getName();
Map variableMap = ExchangeHelper.createVariableMap(exchange);
Context velocityContext = new VelocityContext(variableMap);
// let velocity parse and generate the result in buffer
VelocityEngine engine = getVelocityEngine();
if (log.isDebugEnabled()) {
log.debug("Velocity is evaluating using velocity context: " + variableMap);
}
engine.evaluate(velocityContext, buffer, logTag, reader);
// now lets output the results to the exchange
Message out = exchange.getOut(true);
out.setBody(buffer.toString());
out.setHeader("org.apache.camel.velocity.resource", resource);
Map<String, Object> headers = (Map<String, Object>)velocityContext.get("headers");
for (String key : headers.keySet()) {
out.setHeader(key, headers.get(key));
}
}
}