TelnetFrameworkAndroid.java

/*
 * Copyright (C) 2012 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.
 */
package com.motorola.studio.android.utilities;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;

import org.apache.commons.net.telnet.TelnetClient;

/**
 * DESCRIPTION: This class defines the framework for telnet services to
 * comunicate with phoe or emulator devices. <BR>
 * RESPONSIBILITY: Provide telnet connection <BR>
 * COLABORATORS: none <BR>
 * USAGE: This class should be instantiated whenever a telnet connection to a
 * phone or emulator device is needed. <BR>
 */
public class TelnetFrameworkAndroid
{

    //private InputStreamReader responseReader;

    //private PrintWriter commandWriter;

    private TelnetClient telnetClient;

    private long timeout = 5000L;

    /**
     * Connect to a device using telnet.
     * 
     * @param telnetHost
     *            the telnet host IP address
     * @param telnetPort
     *            the telnet port
     * 
     * @throws MotodevException
     *             when the connection cannot be established
     */
    public synchronized void connect(String telnetHost, int telnetPort) throws IOException
    {
        if ((telnetClient == null) || ((telnetClient != null) && (!telnetClient.isConnected())))
        {
            telnetClient = new TelnetClient(telnetHost);
            telnetClient.connect(telnetHost, telnetPort);
        }
    }

    /**
     * Disconnect a telnet connection to a device
     * 
     * @throws MotodevException
     *             when the disconnection cannot be executed
     */
    public synchronized void disconnect() throws IOException
    {
        if ((telnetClient != null) && (telnetClient.isConnected()))
        {
            telnetClient.disconnect();
        }
    }

    /**
     * @return 
     *
     */
    public synchronized String write(String telnetInputText, String[] waitFor) throws IOException
    {
        PrintWriter commandWriter = null;
        try
        {
            commandWriter = new PrintWriter(telnetClient.getOutputStream());
            commandWriter.println(telnetInputText);
            commandWriter.flush();
            if (waitFor != null)
            {
                return waitFor(waitFor);
            }
        }
        finally
        {
            if (commandWriter != null)
            {
                commandWriter.close();
            }
        }

        return null;
    }

    /**
     * Tests if the telnet client instance is connected
     * 
     * @return true if it is connected; false otherwise
     */
    public boolean isConnected()
    {
        boolean connected = false;
        if (telnetClient != null)
        {
            connected = telnetClient.isConnected();
        }
        return connected;
    }

    /**
     *
     */
    public String waitFor(String[] waitForArray) throws IOException
    {
        InputStreamReader responseReader = null;
        StringBuffer answerFromRemoteHost = new StringBuffer();

        try
        {
            responseReader = new InputStreamReader(telnetClient.getInputStream());

            boolean found = false;

            do
            {
                char readChar = 0;
                long currentTime = System.currentTimeMillis();
                long timeoutTime = currentTime + timeout;

                while (readChar == 0)
                {
                    if (responseReader == null)
                    {
                        // responseReader can only be set to null if method
                        // releaseTelnetInputStreamReader()
                        // has been called, which should happen if host becomes
                        // unavailable.
                        throw new IOException(
                                "Telnet host is unavailable; stopped waiting for answer.");
                    }

                    if (responseReader.ready())
                    {
                        readChar = (char) responseReader.read();
                    }
                    else
                    {
                        try
                        {
                            Thread.sleep(50);
                        }
                        catch (InterruptedException e)
                        {
                            // Do nothing
                        }
                    }

                    currentTime = System.currentTimeMillis();

                    if ((!responseReader.ready()) && (currentTime > timeoutTime))
                    {
                        throw new IOException(
                                "A timeout has occured when trying to read the telnet stream");
                    }
                }

                answerFromRemoteHost.append(readChar);

                for (String aWaitFor : waitForArray)
                {
                    found = answerFromRemoteHost.toString().contains(aWaitFor);
                }

            }
            while (!found);
        }
        finally
        {
            if (responseReader != null)
            {
                responseReader.close();
            }
        }

        return answerFromRemoteHost.toString();
    }

    /**
     * Retrieves the input stream associated to this telnet connection
     */
    public InputStream getInputStream()
    {
        InputStream s = null;
        if (telnetClient != null)
        {
            s = telnetClient.getInputStream();
        }
        return s;
    }

    /**
     * Retrieves the output stream associated to this telnet connection
     */
    public OutputStream getOutputStream()
    {
        OutputStream s = null;
        if (telnetClient != null)
        {
            s = telnetClient.getOutputStream();
        }
        return s;
    }
}