Assign ByteInputStream to InputStream keeping bind to terminal emulator

Tar.Aldarion

I am trying to connect to a terminal emulator using a library in android, this will connect to a serial device and should show me sent/received data. To attach to a terminal session I need to provide an inputStream to setTermIn(InputStream) and an outputStream to setTermOut(OutputStream).

I initialize and attach some streams like so in onCreate(), these are just initial streams and are not attached to the data I want to be sending/receiving.

private OutputStream bos;
private InputStream bis;

...

byte[] a = new byte[4096];
bis = new ByteArrayInputStream(a);
bos = new ByteArrayOutputStream();
session.setTermIn(bis);
session.setTermOut(bos);
/* Attach the TermSession to the EmulatorView. */
mEmulatorView.attachSession(session);

I now want to assign the streams to data as I send and receive data. In The sendData() method, which I call every time I press enter, I have:

public void sendData(byte[] data)
{
        bos = new ByteArrayOutputStream(data.length);         
}

and in the onReceiveData() method, called every time data is received over serial:

public void onDataReceived(int id, byte[] data)
{
        bis = new ByteArrayInputStream(data);           
}

However a ByteArrayInputStream can only ever have the data that was given to it, so it constantly needs to be created as data is sent and received. Now the problem is, I want this data to appear on the terminal, but when I assign bis to the data, it is no longer attached like it was when I called mEmulatorView.attachSession(session);

Is there a way to update what bis is pointing to without breaking the bind that bis has to the terminal?

[-0-]

Unrelated, but why are you using a restricted byte array of 4096? What if the data sent or returned is larger than this?

I wrote an application to SSH to remote hosts and run some greps - often returning lots of data.

In order to handle this I use an InputStream and I just build a String based on the data returned.

try{
    		session = connectionInfo.getSession();
    		if(!session.isConnected()) {session.connect();}
    		
    		   	ChannelExec channelExec = (ChannelExec) session.openChannel("exec");
		    	channelExec.setPty(true);
		    	//logger.info("command : "+command);
		    	System.out.println("command : "+command);
		    	channelExec.setCommand(command);
		    	InputStream inputStream = channelExec.getInputStream();
		    	channelExec.connect();
		    	
		    	while (channelExec.isClosed()!=true) {
		
		            try {
		              output+=streamToString(inputStream);
		
		                } 
		            catch (Exception e) {
		              // TODO Auto-generated catch block
		              e.printStackTrace();
		             }
		            
		           
		    	  }
		    	
    			
		   }

                   catch(Exception e){
		    	
		    	e.printStackTrace();
		    	
		    	}

public static String streamToString(InputStream input)throws Exception 
    { 
    	String output = ""; 
    	while(input.available()>0) 
    	{ 
    		output += ((char)(input.read())); 
    	} 
    	return output; 
    }

I'm sure you could do something similar when handling data returned from the command prompt.

Off topic - but I hope it helps you when you get to that area of your code.

Tar.Aldarion

Thanks, I'll have a look through that! Will probably help later on. I set it to a random number at first as I was just initializing it, when i send and receive data a new stream is made of that size. There is no size to base it off when initializing it. A ByteArrayInputStream can only ever have the data you initialize it with.

My problem is not as described in the OP as I thought I fixed that but the issue still happens. i probably fixed a problem that I have not gotten to yet! Here I can update the data by calling this class and don't have to make a new stream:

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;


//Wrap the ByteArrayInputStream adding the functionality I need.
public class MyBAIsWrapper extends InputStream{
	
	private ByteArrayInputStream wrapped;

	   public MyBAIsWrapper(byte[] data) {
	       wrapped=new ByteArrayInputStream(data);
	   }

	   //Method to refresh with new data
	   public void renew(byte[] newData) {
	       wrapped=new ByteArrayInputStream(newData);
	   }

	   //implement the InputStreamMethods calling the corresponding methods on wrapped
	   public int read() throws IOException {
	      return wrapped.read();
	   }

	   public int read(byte[] b) throws IOException {
	       return wrapped.read(b);
	   }

	   //and so on

}

The original problem has something to do with setting the initial streams to the terminal, as I can not write anything to the screen even if I don't change the streams. The initial stream isn't working right.

So below the terminal will come up with hello written in it, nothing else will be written.

TermSession session = new TermSession();

        byte[] a = new byte[]{'h','e', 'l', 'l', 'o'};
        bis = new ByteArrayInputStream(a);
        bos = new ByteArrayOutputStream();
        session.write("testTWO");
        session.setTermIn(bis);
        session.setTermOut(bos);
        session.write("testONE");

        /* Attach the TermSession to the EmulatorView. */
        mEmulatorView.attachSession(session);
        mSession = session;
        try {
            bos.write(a);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        session.write("test");