Home | History | Annotate | Download | only in service 
      1 package com.googlecode.android_scripting.service;
      2 
      3 import android.annotation.TargetApi;
      4 import android.os.Bundle;
      5 import android.os.Handler;
      6 import android.os.HandlerThread;
      7 import android.os.Message;
      8 import android.os.RemoteException;
      9 
     10 import com.googlecode.android_scripting.Log;
     11 import com.googlecode.android_scripting.jsonrpc.JsonRpcResult;
     12 import com.googlecode.android_scripting.jsonrpc.RpcReceiverManager;
     13 import com.googlecode.android_scripting.jsonrpc.RpcReceiverManagerFactory;
     14 import com.googlecode.android_scripting.rpc.MethodDescriptor;
     15 
     16 import org.json.JSONException;
     17 import org.json.JSONObject;
     18 
     19 /**
     20  * Class responsible for Handling messages that came through the FacadeService
     21  * interface.
     22  * <br>
     23  * Please refer to {@link FacadeService} for details on how to use.
     24  */
     25 @TargetApi(3)
     26 public class MessageHandler extends Handler {
     27 
     28     private static final int SL4A_ACTION = 0;
     29     private static final int DEFAULT_SENDING_ID = 0;
     30 
     31     // Android sets this to -1 when the message is not sent by a Messenger.
     32     // see http://developer.android.com/reference/android/os/Message.html#sendingUid
     33     private static final int DEFAULT_UNSET_SENDING_ID = 1;
     34 
     35     // Keys for the Bundles.
     36     private static final String SL4A_METHOD = "sl4aMethod";
     37     private static final String SL4A_RESULT = "sl4aResult";
     38 
     39     private final RpcReceiverManagerFactory mRpcReceiverManagerFactory;
     40 
     41     public MessageHandler(HandlerThread handlerThread,
     42                           RpcReceiverManagerFactory rpcReceiverManagerFactory) {
     43         super(handlerThread.getLooper());
     44         this.mRpcReceiverManagerFactory = rpcReceiverManagerFactory;
     45     }
     46 
     47     /**
     48      * Handles messages for the service. It does this via the same mechanism used
     49      * for RPCs through RpcManagers.
     50      *
     51      * @param message The message that contains the method and parameters to
     52      *     execute.
     53      */
     54     @Override
     55     public void handleMessage(Message message) {
     56         Log.d("Handling Remote request");
     57         int senderId = message.sendingUid == DEFAULT_UNSET_SENDING_ID ?
     58                 DEFAULT_SENDING_ID : message.sendingUid;
     59         if (message.what == SL4A_ACTION) {
     60             RpcReceiverManager receiverManager;
     61             if (mRpcReceiverManagerFactory.getRpcReceiverManagers().containsKey(senderId)) {
     62                 receiverManager = mRpcReceiverManagerFactory.getRpcReceiverManagers().get(senderId);
     63             } else {
     64                 receiverManager = mRpcReceiverManagerFactory.create(senderId);
     65             }
     66             Bundle sl4aRequest = message.getData();
     67             String method = sl4aRequest.getString(SL4A_METHOD);
     68             if (method == null || "".equals(method)) {
     69                 Log.e("No SL4A method specified on the Bundle. Specify one with "
     70                         + SL4A_METHOD);
     71                 return;
     72             }
     73             MethodDescriptor rpc = receiverManager.getMethodDescriptor(method);
     74             if (rpc == null) {
     75                 Log.e("Unknown RPC: \"" + method + "\"");
     76                 return;
     77             }
     78             try {
     79                 Log.d("Invoking method " + rpc.getName());
     80                 Object result = rpc.invoke(receiverManager, sl4aRequest);
     81                 // Only return a result if we were passed a Messenger. Otherwise assume
     82                 // client did not care for the response.
     83                 if (message.replyTo != null) {
     84                     Message reply = Message.obtain();
     85                     Bundle sl4aResponse = new Bundle();
     86                     putResult(senderId, result, sl4aResponse);
     87                     reply.setData(sl4aResponse);
     88                     message.replyTo.send(reply);
     89                 }
     90             } catch (RemoteException e) {
     91                 Log.e("Could not send reply back to client", e);
     92             } catch (Throwable t) {
     93                 Log.e("Exception while executing sl4a method", t);
     94             }
     95         }
     96     }
     97 
     98     private void putResult(int id, Object result, Bundle reply) {
     99         JSONObject json;
    100         try {
    101             if (result instanceof Throwable) {
    102                 json = JsonRpcResult.error(id, (Throwable) result);
    103             } else {
    104                 json = JsonRpcResult.result(id, result);
    105             }
    106         } catch (JSONException e) {
    107             // There was an error converting the result to JSON. This shouldn't
    108             // happen normally.
    109             Log.e("Caught exception when filling JSON result.", e);
    110             reply.putString(SL4A_RESULT, e.toString());
    111             return;
    112         }
    113         Log.d("Returning result: " + json.toString());
    114         reply.putString(SL4A_RESULT, json.toString());
    115     }
    116 }
    117