Add protected method to connect channel to streams

These methods can be overridden by subclasses of existing channels
to write to/read from streams,
for example, to replay some captured stream,
or just to do some tests based on ByteArrayInputStream.

Signed-off-by: Andrés Alcarraz <alcarraz@gmail.com>

jpos/src/main/java/org/jpos/iso/BaseChannel.java

@@ -291,6 +291,20 @@ protected void connect (Socket socket)
         setChanged();
         notifyObservers();
     }
+
+    /**
+     * Allow the channel to be connected to a pair of input and output streams.
+     * <p> 
+     * For instance for taking input from or outputting to a file or standard input/ouput.  
+     * 
+     * @param in Where to read from.
+     * @param out Where to write to.
+     */
+    protected void connect(InputStream in, OutputStream out) {
+        usable = in != null || out != null; //at least one of them has to be not null
+        if (in != null) serverIn = new DataInputStream(in);
+        if (out != null) serverOut = new DataOutputStream(out);
+    }
     protected void postConnectHook() throws IOException {
         // do nothing
     }

jpos/src/main/java/org/jpos/iso/channel/XMLChannel.java

@@ -22,9 +22,12 @@
 import org.jpos.iso.packager.XMLPackager;
 
 import java.io.BufferedReader;
+import java.io.DataInputStream;
 import java.io.EOFException;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.InputStreamReader;
+import java.io.OutputStream;
 import java.net.ServerSocket;
 import java.net.Socket;
 
@@ -117,4 +120,9 @@ public void disconnect () throws IOException {
             reader.close ();
         reader = null;
     }
+
+    protected void connect(InputStream in, OutputStream out) {
+        super.connect(in, out);
+        reader = new BufferedReader(new InputStreamReader(in));
+    }
 }