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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.car.obd2.connections;
     18 
     19 import android.bluetooth.BluetoothAdapter;
     20 import android.bluetooth.BluetoothDevice;
     21 import android.bluetooth.BluetoothSocket;
     22 import android.util.Log;
     23 import com.android.car.obd2.Obd2Connection;
     24 import java.io.IOException;
     25 import java.io.InputStream;
     26 import java.io.OutputStream;
     27 import java.util.Objects;
     28 import java.util.UUID;
     29 
     30 public class BluetoothConnection implements Obd2Connection.UnderlyingTransport {
     31 
     32     /**
     33      * This is the well-known UUID for the Bluetooth SPP (Serial Port Profile)
     34      */
     35     private static final UUID SERIAL_PORT_PROFILE = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
     36 
     37     private final BluetoothDevice mDevice;
     38     private BluetoothSocket mSocket = null;
     39 
     40     public static final String TAG = BluetoothConnection.class.getSimpleName();
     41 
     42     public BluetoothConnection(String bluetoothAddress) {
     43         this(BluetoothAdapter.getDefaultAdapter().getRemoteDevice(bluetoothAddress));
     44     }
     45 
     46     public BluetoothConnection(BluetoothDevice device) {
     47         mDevice = Objects.requireNonNull(device);
     48         connect();
     49     }
     50 
     51     @Override
     52     public String getAddress() {
     53         return mDevice.getAddress();
     54     }
     55 
     56     /**
     57      * Establish an RFCOMM connection to the remote device.
     58      *
     59      * Assumes there is no existing connection.
     60      *
     61      * This method may take time to return (or even not return in pathological cases).
     62      * It is a good idea to wrap it in some kind of Promise-like object.
     63      *
     64      * @return true if it could connect, false otherwise
     65      */
     66     private boolean connect() {
     67         try {
     68             mSocket = mDevice.createRfcommSocketToServiceRecord(SERIAL_PORT_PROFILE);
     69             mSocket.connect();
     70         } catch (IOException e) {
     71             Log.w(TAG, "BluetoothConnection couldn't be established due to an exception: " + e);
     72             mSocket = null;
     73             return false;
     74         }
     75         return mSocket.isConnected();
     76     }
     77 
     78     @Override
     79     public boolean isConnected() {
     80         return mSocket != null && mSocket.isConnected();
     81     }
     82 
     83     private void close() {
     84         if (isConnected()) {
     85             try {
     86                 mSocket.close();
     87             } catch (IOException e) {
     88                 // we are letting go of the connection anyway, so log and continue
     89                 Log.w(TAG, "IOException during BluetoothSocket close(): " + e);
     90             } finally {
     91                 mSocket = null;
     92             }
     93         }
     94     }
     95 
     96     @Override
     97     public boolean reconnect() {
     98         close();
     99         return connect();
    100     }
    101 
    102     @Override
    103     public InputStream getInputStream() {
    104         if (isConnected()) {
    105             try {
    106                 return mSocket.getInputStream();
    107             } catch (IOException e) {
    108                 Log.w(TAG, "failed to get Bluetooth input stream: " + e);
    109             }
    110         }
    111         return null;
    112     }
    113 
    114     @Override
    115     public OutputStream getOutputStream() {
    116         if (isConnected()) {
    117             try {
    118                 return mSocket.getOutputStream();
    119             } catch (IOException e) {
    120                 Log.w(TAG, "failed to get Bluetooth output stream: " + e);
    121             }
    122         }
    123         return null;
    124     }
    125 }
    126