/*
* Copyright: Almende B.V. (2014), Rotterdam, The Netherlands
* License: The Apache Software License, Version 2.0
*/
package com.almende.eve.agent;
import java.io.IOException;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.net.URI;
import com.almende.eve.agent.callback.AsyncCallback;
import com.almende.eve.agent.callback.AsyncCallbackQueue;
import com.almende.eve.agent.callback.SyncCallback;
import com.almende.eve.rpc.jsonrpc.JSONMessage;
import com.almende.eve.rpc.jsonrpc.JSONRPC;
import com.almende.eve.rpc.jsonrpc.JSONRPCException;
import com.almende.eve.rpc.jsonrpc.JSONRPCException.CODE;
import com.almende.eve.rpc.jsonrpc.JSONRequest;
import com.almende.eve.rpc.jsonrpc.JSONResponse;
import com.almende.util.TypeUtil;
import com.fasterxml.jackson.databind.JsonNode;
/**
* A factory for creating AgentProxy objects.
*/
public class AgentProxyFactory {
private AgentHost host = null;
/**
* Instantiates a new agent proxy factory.
*
* @param host
* the host
*/
public AgentProxyFactory(final AgentHost host) {
this.host = host;
}
/**
* Gen proxy.
*
* @param <T>
* the generic type
* @param receiverUrl
* the receiver url
* @param agentInterface
* the agent interface
* @param proxyId
* the proxy id
* @return the t
*/
@SuppressWarnings("unchecked")
public <T extends AgentInterface> T genProxy(final URI receiverUrl,
final Class<T> agentInterface, final String proxyId) {
// http://docs.oracle.com/javase/1.4.2/docs/guide/reflection/proxy.html
final T proxy = (T) Proxy.newProxyInstance(
agentInterface.getClassLoader(),
new Class[] { agentInterface }, new InvocationHandler() {
@Override
public Object invoke(final Object proxy,
final Method method, final Object[] args)
throws JSONRPCException, IOException {
AgentInterface agent = (T) proxy;
// TODO: if method calls for Namespace getter, return
// new proxy for subtype. All calls to that proxy need
// to add namespace to method name for JSON-RPC.
if (method.getName().equals("getId")) {
return proxyId;
} else if (method.getName().equals("receive")
&& args.length > 1) {
JSONResponse response = null;
if (args[0] != null) {
response = receive(args[0]);
}
if (response != null) {
JsonNode id = null;
if (response.getId() != null) {
id = response.getId();
}
final AsyncCallbackQueue<JSONResponse> cbs = host
.getCallbackQueue(proxyId,
JSONResponse.class);
if (cbs != null) {
final AsyncCallback<JSONResponse> callback = cbs
.pull(id);
if (callback != null) {
if (response.getError() != null) {
callback.onFailure(response
.getError());
} else {
callback.onSuccess(response);
}
}
}
}
return null;
} else {
final JSONRequest request = JSONRPC.createRequest(
method, args);
final SyncCallback<JSONResponse> callback = new SyncCallback<JSONResponse>();
final AsyncCallbackQueue<JSONResponse> cbs = host
.getCallbackQueue(proxyId,
JSONResponse.class);
if (cbs != null) {
cbs.push(request.getId(), "", callback);
}
try {
host.sendAsync(receiverUrl, request, agent,
null);
} catch (final IOException e1) {
throw new JSONRPCException(
CODE.REMOTE_EXCEPTION, "", e1);
}
JSONResponse response;
try {
response = callback.get();
} catch (final Exception e) {
throw new JSONRPCException(
CODE.REMOTE_EXCEPTION, "", e);
}
final JSONRPCException err = response.getError();
if (err != null) {
throw err;
} else if (response.getResult() != null
&& !method.getReturnType()
.equals(Void.TYPE)) {
return TypeUtil.inject(response.getResult(),
method.getGenericReturnType());
} else {
return null;
}
}
}
});
return proxy;
}
/**
* Receive.
*
* @param arg
* the arg
* @return the jSON response
* @throws JSONRPCException
* the jSONRPC exception
* @throws IOException
* Signals that an I/O exception has occurred.
*/
private JSONResponse receive(final Object arg) throws JSONRPCException,
IOException {
final JSONMessage jsonMsg = Agent.jsonConvert(arg);
if (jsonMsg instanceof JSONResponse) {
return (JSONResponse) jsonMsg;
}
return null;
}
}