/**
* Helios, OpenSource Monitoring
* Brought to you by the Helios Development Group
*
* Copyright 2007, Helios Development Group and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*
*/
package org.helios.apmrouter.dataservice.json;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import java.lang.reflect.Method;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.log4j.Logger;
import org.jboss.netty.channel.Channel;
import org.json.JSONObject;
/**
* <p>Title: JSONRequestHandlerImpl</p>
* <p>Description: Invocable implementation wrapper around a {@link JSONRequestHandler} annotated method.</p>
* <p>Company: Helios Development Group LLC</p>
* @author Whitehead (nwhitehead AT heliosdev DOT org)
* <p><code>org.helios.apmrouter.dataservice.json.JSONRequestHandlerImpl</code></p>
*/
public class JSONRequestHandlerImpl implements JSONDataService {
/** Static class logger */
protected static final Logger LOG = Logger.getLogger(JSONRequestHandlerImpl.class);
/** The handler implementation instance */
protected final Object impl;
/** The invocation method handle */
protected final MethodHandle methodHandle;
/** The handler name */
protected final String name;
/** The service name */
protected final String serviceName;
/**
* Creates a new JSONRequestHandlerImpl
* @param impl The handler implementation instance
* @param methodHandle The invocation method handle
* @param name The handler name
* @param serviceName The service name
*/
public JSONRequestHandlerImpl(Object impl, MethodHandle methodHandle, String name, String serviceName) {
this.impl = impl;
this.methodHandle = methodHandle;
this.name = name;
this.serviceName = serviceName;
}
/**
* {@inheritDoc}
*
*/
@Override
public void processRequest(JsonRequest request, Channel channel) {
try {
methodHandle.invoke(impl, request, channel);
} catch (Throwable e) {
LOG.error("Failed to invoke handler [" + name + "]", e);
channel.write(renderInvocationError(e));
}
}
/**
* Renders a JSONObject from the passed throwable
* @param t The throwable to render
* @return the rendered JSONObject
*/
protected JSONObject renderInvocationError(Throwable t) {
try {
JSONObject err = new JSONObject();
err.putOnce(JSONRequestRouter.REQUEST_FLAG, "err");
err.putOnce(JSONRequestRouter.SERVICE_NAME, serviceName);
err.putOnce(JSONRequestRouter.OP_NAME, name);
err.putOnce(JSONRequestRouter.ERR_NAME, t.getMessage());
return err;
} catch (Exception ex) {
throw new RuntimeException("Failed to build error response", ex);
}
}
/**
* Generates a map of handlers keyed by the handler name
* @param serviceName The service name these handlers are being atached to
* @param serviceImpl The service implementation
* @return A map of handlers keyed by the handler name
*/
public static Map<String, JSONRequestHandlerImpl> generateHandlers(String serviceName, Object serviceImpl) {
Map<String, JSONRequestHandlerImpl> map = new ConcurrentHashMap<String, JSONRequestHandlerImpl>();
for(Method m: serviceImpl.getClass().getMethods()) {
JSONRequestHandler rh = m.getAnnotation(JSONRequestHandler.class);
if(rh!=null) {
String name = rh.name();
try {
MethodType desc = MethodType.methodType(void.class, new Class[]{JsonRequest.class, Channel.class});
MethodHandle mh = MethodHandles.lookup().findVirtual(serviceImpl.getClass(), m.getName(), desc);
map.put(name, new JSONRequestHandlerImpl(serviceImpl, mh, name, serviceName));
} catch (Exception e) {
}
}
}
for(Method m: serviceImpl.getClass().getDeclaredMethods()) {
JSONRequestHandler rh = m.getAnnotation(JSONRequestHandler.class);
if(rh!=null) {
String name = rh.name();
try {
MethodType desc = MethodType.methodType(void.class, new Class[]{JsonRequest.class, Channel.class});
MethodHandle mh = MethodHandles.lookup().findVirtual(serviceImpl.getClass(), m.getName(), desc);
map.put(name, new JSONRequestHandlerImpl(serviceImpl, mh, name, serviceName));
} catch (Exception e) {
}
}
}
return map;
}
}