Java tutorial
package uk.ac.gcu.bluedroid; /* * Copyright (C) 2009 The Android Open Source Project * * Licensed 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. */ import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.ArrayList; import java.util.UUID; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import uk.ac.gcu.bluedroid.game.GameState; import uk.ac.gcu.bluedroid.game.TurnInfo; import uk.ac.gcu.bluedroid.util.Util; import com.google.gson.Gson; import com.google.gson.GsonBuilder; import android.bluetooth.BluetoothAdapter; import android.bluetooth.BluetoothDevice; import android.bluetooth.BluetoothServerSocket; import android.bluetooth.BluetoothSocket; import android.content.Context; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.util.Log; /** * This class does all the work for setting up and managing Bluetooth * connections with other devices. It has a thread that listens for incoming * connections, a thread for connecting with a device, and a thread for * performing data transmissions when connected. */ public class BluetoothChatService { // Debugging private static final String TAG = "BluetoothChatService"; private static final boolean D = true; // Name for the SDP record when creating server socket private static final String NAME_SECURE = "BluetoothChatSecure"; private static final String NAME_INSECURE = "BluetoothChatInsecure"; // Unique UUID for this application private static final UUID MY_UUID_SECURE = UUID.fromString("fa87c0d0-afac-11de-8a39-0800200c9a66"); private static final UUID MY_UUID_INSECURE = UUID.fromString("8ce255c0-200a-11e0-ac64-0800200c9a66"); // Member fields private final BluetoothAdapter mAdapter; private final Handler mHandler; private AcceptThread mSecureAcceptThread; private AcceptThread mInsecureAcceptThread; private ConnectThread mConnectThread; private ConnectedThread mConnectedThread; private int mState; // Time to wait for acknowledge (in milliseconds) private static final int ACK_WAIT = 3000; // Acknowledge Handler Handler ackHandler; ArrayList<String> tags; // JSON parser Gson gson; // Constants that indicate the current connection state public static final int STATE_NONE = 0; // we're doing nothing public static final int STATE_LISTEN = 1; // now listening for incoming // connections public static final int STATE_CONNECTING = 2; // now initiating an outgoing // connection public static final int STATE_CONNECTED = 3; // now connected to a remote // device /** * Constructor. Prepares a new MainActivity session. * * @param context * The UI Activity Context * @param handler * A Handler to send messages back to the UI Activity */ public BluetoothChatService(Context context, Handler handler) { GsonBuilder builder = new GsonBuilder(); gson = builder.create(); ackHandler = new Handler(); mAdapter = BluetoothAdapter.getDefaultAdapter(); mState = STATE_NONE; mHandler = handler; tags = new ArrayList<String>(); } /** * Set the current state of the chat connection * * @param state * An integer defining the current connection state */ private synchronized void setState(int state) { if (D) Log.d(TAG, "setState() " + mState + " -> " + state); mState = state; // Give the new state to the Handler so the UI Activity can update mHandler.obtainMessage(MainActivity.MESSAGE_STATE_CHANGE, state, -1).sendToTarget(); } /** * Return the current connection state. */ public synchronized int getState() { return mState; } /** * Start the chat service. Specifically start AcceptThread to begin a * session in listening (server) mode. Called by the Activity onResume() */ public synchronized void start() { if (D) Log.d(TAG, "start"); // Cancel any thread attempting to make a connection if (mConnectThread != null) { mConnectThread.cancel(); mConnectThread = null; } // Cancel any thread currently running a connection if (mConnectedThread != null) { mConnectedThread.cancel(); mConnectedThread = null; } setState(STATE_LISTEN); // Start the thread to listen on a BluetoothServerSocket if (mSecureAcceptThread == null) { mSecureAcceptThread = new AcceptThread(true); mSecureAcceptThread.start(); } if (mInsecureAcceptThread == null) { mInsecureAcceptThread = new AcceptThread(false); mInsecureAcceptThread.start(); } } /** * Start the ConnectThread to initiate a connection to a remote device. * * @param device * The BluetoothDevice to connect * @param secure * Socket Security type - Secure (true) , Insecure (false) */ public synchronized void connect(BluetoothDevice device, boolean secure) { if (D) Log.d(TAG, "connect to: " + device); // Cancel any thread attempting to make a connection if (mState == STATE_CONNECTING) { if (mConnectThread != null) { mConnectThread.cancel(); mConnectThread = null; } } // Cancel any thread currently running a connection if (mConnectedThread != null) { mConnectedThread.cancel(); mConnectedThread = null; } // Start the thread to connect with the given device mConnectThread = new ConnectThread(device, secure); mConnectThread.start(); setState(STATE_CONNECTING); } /** * Start the ConnectedThread to begin managing a Bluetooth connection * * @param socket * The BluetoothSocket on which the connection was made * @param device * The BluetoothDevice that has been connected */ public synchronized void connected(BluetoothSocket socket, BluetoothDevice device, final String socketType) { if (D) Log.d(TAG, "connected, Socket Type:" + socketType); // Cancel the thread that completed the connection if (mConnectThread != null) { mConnectThread.cancel(); mConnectThread = null; } // Cancel any thread currently running a connection if (mConnectedThread != null) { mConnectedThread.cancel(); mConnectedThread = null; } // Cancel the accept thread because we only want to connect to one // device if (mSecureAcceptThread != null) { mSecureAcceptThread.cancel(); mSecureAcceptThread = null; } if (mInsecureAcceptThread != null) { mInsecureAcceptThread.cancel(); mInsecureAcceptThread = null; } // Start the thread to manage the connection and perform transmissions mConnectedThread = new ConnectedThread(socket, socketType); mConnectedThread.start(); // Send the name of the connected device back to the UI Activity Message msg = mHandler.obtainMessage(MainActivity.MESSAGE_DEVICE_NAME); Bundle bundle = new Bundle(); bundle.putString(MainActivity.DEVICE_NAME, device.getName()); msg.setData(bundle); mHandler.sendMessage(msg); setState(STATE_CONNECTED); } /** * Stop all threads */ public synchronized void stop() { if (D) Log.d(TAG, "stop"); if (mConnectThread != null) { mConnectThread.cancel(); mConnectThread = null; } if (mConnectedThread != null) { mConnectedThread.cancel(); mConnectedThread = null; } if (mSecureAcceptThread != null) { mSecureAcceptThread.cancel(); mSecureAcceptThread = null; } if (mInsecureAcceptThread != null) { mInsecureAcceptThread.cancel(); mInsecureAcceptThread = null; } setState(STATE_NONE); } public void send(String _class, Object obj) { Wrapper wrapper = new Wrapper(_class, Wrapper.MESSAGE, gson.toJson(obj)); write(wrapper); } /** * Write to the ConnectedThread in an unsynchronized manner * * @param out * The bytes to write * @see ConnectedThread#write(Wrapper) */ private void write(Wrapper out) { // Create temporary object ConnectedThread r; // Synchronize a copy of the ConnectedThread synchronized (this) { if (mState != STATE_CONNECTED) return; r = mConnectedThread; } // Perform the write unsynchronized r.write(out); } /** * Indicate that the connection attempt failed and notify the UI Activity. */ private void connectionFailed() { // Send a failure message back to the Activity Message msg = mHandler.obtainMessage(MainActivity.MESSAGE_TOAST); Bundle bundle = new Bundle(); bundle.putString(MainActivity.TOAST, "Unable to connect device"); msg.setData(bundle); mHandler.sendMessage(msg); // Start the service over to restart listening mode BluetoothChatService.this.start(); } /** * Indicate that the connection was lost and notify the UI Activity. */ private void connectionLost() { // Send a failure message back to the Activity Message msg = mHandler.obtainMessage(MainActivity.MESSAGE_TOAST); Bundle bundle = new Bundle(); bundle.putString(MainActivity.TOAST, "Device connection was lost"); msg.setData(bundle); mHandler.sendMessage(msg); // Start the service over to restart listening mode BluetoothChatService.this.start(); } /** * This thread runs while listening for incoming connections. It behaves * like a server-side client. It runs until a connection is accepted (or * until cancelled). */ private class AcceptThread extends Thread { // The local server socket private final BluetoothServerSocket mmServerSocket; private String mSocketType; public AcceptThread(boolean secure) { BluetoothServerSocket tmp = null; mSocketType = secure ? "Secure" : "Insecure"; // Create a new listening server socket try { if (secure) { tmp = mAdapter.listenUsingRfcommWithServiceRecord(NAME_SECURE, MY_UUID_SECURE); } else { // listenUsingInsecureRfcommWithServiceRecord(String name, // UUID uuid) // tmp = // mAdapter.listenUsingInsecureRfcommWithServiceRecord(NAME_INSECURE, // MY_UUID_INSECURE); tmp = mAdapter.listenUsingRfcommWithServiceRecord(NAME_INSECURE, MY_UUID_INSECURE); } } catch (IOException e) { Log.e(TAG, "Socket Type: " + mSocketType + "listen() failed", e); } mmServerSocket = tmp; } public void run() { if (D) Log.d(TAG, "Socket Type: " + mSocketType + "BEGIN mAcceptThread" + this); setName("AcceptThread" + mSocketType); BluetoothSocket socket = null; // Listen to the server socket if we're not connected while (mState != STATE_CONNECTED) { try { // This is a blocking call and will only return on a // successful connection or an exception socket = mmServerSocket.accept(); } catch (IOException e) { Log.e(TAG, "Socket Type: " + mSocketType + "accept() failed", e); break; } // If a connection was accepted if (socket != null) { synchronized (BluetoothChatService.this) { switch (mState) { case STATE_LISTEN: case STATE_CONNECTING: // Situation normal. Start the connected thread. connected(socket, socket.getRemoteDevice(), mSocketType); break; case STATE_NONE: case STATE_CONNECTED: // Either not ready or already connected. Terminate // new socket. try { socket.close(); } catch (IOException e) { Log.e(TAG, "Could not close unwanted socket", e); } break; } } } } if (D) Log.i(TAG, "END mAcceptThread, socket Type: " + mSocketType); } public void cancel() { if (D) Log.d(TAG, "Socket Type" + mSocketType + "cancel " + this); try { mmServerSocket.close(); } catch (IOException e) { Log.e(TAG, "Socket Type" + mSocketType + "close() of server failed", e); } } } /** * This thread runs while attempting to make an outgoing connection with a * device. It runs straight through; the connection either succeeds or * fails. */ private class ConnectThread extends Thread { private final BluetoothSocket mmSocket; private final BluetoothDevice mmDevice; private String mSocketType; public ConnectThread(BluetoothDevice device, boolean secure) { mmDevice = device; BluetoothSocket tmp = null; mSocketType = secure ? "Secure" : "Insecure"; // Get a BluetoothSocket for a connection with the // given BluetoothDevice try { if (secure) { tmp = device.createRfcommSocketToServiceRecord(MY_UUID_SECURE); } else { // tmp = // device.createInsecureRfcommSocketToServiceRecord(MY_UUID_INSECURE); tmp = device.createRfcommSocketToServiceRecord(MY_UUID_INSECURE); } } catch (IOException e) { Log.e(TAG, "Socket Type: " + mSocketType + "create() failed", e); } mmSocket = tmp; } public void run() { Log.i(TAG, "BEGIN mConnectThread SocketType:" + mSocketType); setName("ConnectThread" + mSocketType); // Always cancel discovery because it will slow down a connection mAdapter.cancelDiscovery(); // Make a connection to the BluetoothSocket try { // This is a blocking call and will only return on a // successful connection or an exception mmSocket.connect(); } catch (IOException e) { // Close the socket try { mmSocket.close(); } catch (IOException e2) { Log.e(TAG, "unable to close() " + mSocketType + " socket during connection failure", e2); } connectionFailed(); return; } // Reset the ConnectThread because we're done synchronized (BluetoothChatService.this) { mConnectThread = null; } // Start the connected thread connected(mmSocket, mmDevice, mSocketType); } public void cancel() { try { mmSocket.close(); } catch (IOException e) { Log.e(TAG, "close() of connect " + mSocketType + " socket failed", e); } } } /** * This thread runs during a connection with a remote device. It handles all * incoming and outgoing transmissions. */ private class ConnectedThread extends Thread { private final BluetoothSocket mmSocket; private final InputStream mmInStream; private final OutputStream mmOutStream; public ConnectedThread(BluetoothSocket socket, String socketType) { Log.d(TAG, "create ConnectedThread: " + socketType); mmSocket = socket; InputStream tmpIn = null; OutputStream tmpOut = null; // Get the BluetoothSocket input and output streams try { tmpIn = socket.getInputStream(); tmpOut = socket.getOutputStream(); } catch (IOException e) { Log.e(TAG, "temp sockets not created", e); } mmInStream = tmpIn; mmOutStream = tmpOut; } public boolean isJSONValid(String test) { try { new JSONObject(test); } catch (JSONException ex) { try { new JSONArray(test); } catch (JSONException ex2) { return false; } } return true; } public void run() { Log.i(TAG, "BEGIN mConnectedThread"); byte[] buffer = new byte[20000]; int bytes; // Keep listening to the InputStream while connected while (true) { try { // Read from the InputStream bytes = mmInStream.read(buffer); String json = new String(buffer, 0, bytes); while (!isJSONValid(json)) { bytes = mmInStream.read(buffer); json = json.concat(new String(buffer, 0, bytes)); } Wrapper wrapper = gson.fromJson(json, Wrapper.class); switch (wrapper.type) { case Wrapper.ACK: Log.d(TAG, "Acknowledge for message " + wrapper.message + " received."); // Do not send the message again tags.remove(wrapper.message); break; case Wrapper.MESSAGE: Object obj = null; if (wrapper._class.equals("string")) obj = gson.fromJson(wrapper.message, String.class); else if (wrapper._class.equals("state")) obj = gson.fromJson(wrapper.message, GameState.class); else if (wrapper._class.equals("turn_info")) obj = gson.fromJson(wrapper.message, TurnInfo.class); mHandler.obtainMessage(MainActivity.MESSAGE_RECEIVED, obj).sendToTarget(); // Send ACK if (wrapper.hash == null || wrapper.hash.equals(Util.hash(wrapper.message))) write(new Wrapper("string", Wrapper.ACK, String.valueOf(wrapper.time))); break; } } catch (IOException e) { Log.e(TAG, "disconnected", e); connectionLost(); // Start the service over to restart listening mode BluetoothChatService.this.start(); break; } } } /** * Write to the connected OutStream. * * @param buffer * The bytes to write */ public void write(final Wrapper buffer) { Runnable writemsg = new Runnable() { @Override public void run() { try { if (!tags.contains(String.valueOf(buffer.time))) return; mmOutStream.write(gson.toJson(buffer).getBytes()); if (buffer.type != Wrapper.ACK) { Log.d(TAG, "Sending message " + String.valueOf(buffer.time)); mHandler.obtainMessage(MainActivity.MESSAGE_SENT, gson.fromJson(buffer.message, Object.class)).sendToTarget(); // Schedule to send message again in ACK_WAIT milliseconds ackHandler.postDelayed(this, ACK_WAIT); } else Log.d(TAG, "Sending ack for " + buffer.message); } catch (IOException e) { Log.e(TAG, "Exception during write", e); } } }; tags.add(String.valueOf(buffer.time)); ackHandler.post(writemsg); } public void cancel() { try { mmSocket.close(); } catch (IOException e) { Log.e(TAG, "close() of connect socket failed", e); } } } }