Android - Bluetooth SPP server (speed test)

/**
    此程式碼單純用來測試速度用 (伺服端)
    https://www.plurk.com/p/lhxlfk
*/

package org.spptest2;

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothServerSocket;
import android.bluetooth.BluetoothSocket;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;

public class MainActivity extends AppCompatActivity {



    final static private String SERVICE_UUID = "00001101-0000-1000-8000-00805F9B34FB";
    static private String NAME = "bluetoothComm";

    //請參照我貼的 client 版本
    static private MT cmt = new MT();
    static private IT cit = new IT();
    static private ST cst = new ST();

    static class MT extends Thread{
        public void run(){
            BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();

            adapter.enable();

            try {
                while (!adapter.isEnabled()){
                    sleep(10);
                }
            } catch (InterruptedException e) {
                push(e.getMessage());
                e.printStackTrace();
                return;
            }
            push("self address: "+adapter.getAddress());

            BluetoothServerSocket serverSocket = null;
            try {
                while (true){
                    //也許是我忘記 close() 的關係，導致下一次新連線無法正常使用
                    serverSocket = adapter.listenUsingRfcommWithServiceRecord(NAME, UUID.fromString(SERVICE_UUID));
                    if(serverSocket==null){
                        push("serverSocket==null");
                        return;
                    }
                    try{
                        BluetoothSocket socket = serverSocket.accept();
                        push("here comes: " + socket.getRemoteDevice().getAddress());
                        OutputStream outputStream = socket.getOutputStream();
                        InputStream inputStream = socket.getInputStream();
                        cit.a(inputStream);

                        push("start!");

                        byte d = 0;
                        while (true) {
                            outputStream.write(0xFF&d++);
                            //實測結果，兩邊同時發送資料是不會影響傳輸速率的
                            //sleep(1);
                            //if(!socket.isConnected())break;
                        }
                    }catch (IOException e){
                        push(e.getMessage());
                        e.printStackTrace();
                    }
                }
            } catch (IOException e) {
                push(e.getMessage());
                e.printStackTrace();
            }
            /*catch (InterruptedException e) {
                e.printStackTrace();
            }*/


        }
    }

    static private class IT extends Thread{
        private InputStream is = null;
        private Object s = new Object();

        public void a(InputStream stream){
            is = stream;
            synchronized (s){
                s.notifyAll();
            }
        }

        public void run(){
            while (true){
                if(is==null){
                    try {
                        synchronized (s) {
                            s.wait();
                        }
                    } catch (InterruptedException e) {
                        return;
                    }
                }
                try {
                    is.read();
                    bps++;
                } catch (IOException e) {
                    is=null;
                    push(e.getMessage());
                    e.printStackTrace();
                }
            }
        }
    }

    static private class ST extends Thread{
        public void run(){
            Object s = new Object();
            try {
                while (true){
                    synchronized (s){
                        s.wait(1000);
                    }
                    handler.sendEmptyMessage(-1);
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    final static private String EMPTY = new String();

    static private void push(String m){
        for (int i=message.length-1;i>0;){
            if(message[i]==null){
                message[i] = EMPTY;
            }else {
                message[i] = message[--i];
            }
        }
        message[0]=m;
    }

    static private int bps = 0;
    static private String[] message = new String[20];
    static private boolean inited = false;

    static private TextView tv = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        tv = (TextView)findViewById(R.id.message);

        if(!inited) {
            inited = true;
            cmt.start();
            cit.start();
            cst.start();
        }

    }

    static private Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            if(msg.what==-1){
                StringBuilder sb = new StringBuilder();
                sb.append(bps*8);
                bps = 0;
                sb.append(" bps\n");
                for(String i : message){
                    sb.append(i);
                    sb.append("\n");
                }
                if(tv!=null){
                    tv.setText(sb);
                }
                super.handleMessage(msg);
            }
        }
    };

}