basereaderutils.java

First of all, the Applet-phone is a SIP User-Agent with audio and text messaging capabilities. But

/*******************************************************************************
* Product of NIST/ITL Advanced Networking Technologies Division (ANTD).        *
*******************************************************************************/
package gov.nist.examples.bps.reader;

import java.util.*;
import javax.sip.message.*; 
import javax.sip.header.*;
import javax.sip.address.*;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
* A few utilities that are used in various places by the stack.
* This is used to convert byte arrays to hex strings etc. Generate
* tags and branch identifiers and odds and ends.
*/
public class BaseReaderUtils 
{
    
    public static final String BRANCH_MAGIC_COOKIE = "z9hG4bK";

     /**
     * to hex converter
     */
    private static final char[] toHex = { '0', '1', '2', '3', '4', '5', '6',
                                          '7', '8', '9', 'a', 'b', 'c', 'd',
                                          'e', 'f' };
 
    /**
     * convert an array of bytes to an hexadecimal string
     * @return a string
     * @param b bytes array to convert to a hexadecimal
     * string
     */
 
    public static String toHexString(byte b[]) {
        int pos = 0;
        char[] c = new char[b.length*2];
        for (int i=0; i< b.length; i++) {
            c[pos++] = toHex[(b[i] >> 4) & 0x0F];
            c[pos++] = toHex[b[i] & 0x0f];
        }
        return new String(c);
    }  
   
      
	/** Generate a tag for a FROM header or TO header. Just return a
	* random 4 digit integer (should be enough to avoid any clashes!)
	* Tags only need to be unique within a call.
	*
	* @return a string that can be used as a tag parameter.
	*/
	public static String generateTag() {
            return new Integer((int)(Math.random() * 10000)).toString();
	}

	/** Generate a cryptographically random identifier that can be used
	* to generate a branch identifier.
	*
	*@return a cryptographically random gloablly unique string that
	*	can be used as a branch identifier.
	*/
	public static String generateBranchId() {
          String b =  new Integer((int)(Math.random() * 10000)).toString() + 
		System.currentTimeMillis();
          try {
              MessageDigest messageDigest = MessageDigest.getInstance("MD5");
              byte bid[] = messageDigest.digest(b.getBytes());
		// cryptographically random string.
		// prepend with a magic cookie to indicate we
		// are bis09 compatible.
              return 	BRANCH_MAGIC_COOKIE +
			toHexString(bid);
           } catch ( NoSuchAlgorithmException e){
	      return null;
           }
	}
        
         public static URI getCleanUri(URI uri) {
        if (uri instanceof SipURI) {
            SipURI sipURI=(SipURI)uri.clone();
            
            Iterator iterator=sipURI.getParameterNames();
            while (iterator!=null && iterator.hasNext()) {
                String name=(String)iterator.next();
                sipURI.removeParameter(name);
            }
            return  sipURI;
        }
        else return  uri;
    }
    
    
    public static  String getKey(Message message,String header) {
        try{
            URI uri=null;
            if (header.equals("From") ) {
                FromHeader fromHeader=(FromHeader)message.getHeader(FromHeader.NAME);
                Address fromAddress=fromHeader.getAddress();
                uri=fromAddress.getURI();
            }
            else
                if (header.equals("To") ) {
                    ToHeader toHeader=(ToHeader)message.getHeader(ToHeader.NAME);
                    Address toAddress=toHeader.getAddress();
                    uri=toAddress.getURI();
                }
                else
                    if (header.equals("Request-URI") ) {
                        uri=
                        ((Request)message).getRequestURI();
                    }
                    else {
                        return null;
                    }
            
            // URI parameters MUST be removed:
            URI cleanedUri = getCleanUri(uri);
            
            String  keyresult=cleanedUri.toString();
            keyresult=keyresult.toLowerCase();
            BaseReaderDebug.println("BaseReaderUtils, getKey(), the key is: " +keyresult);
            return keyresult;
        }
        catch(Exception e) {
            e.printStackTrace();
            return null;
        }
    }
    
    

}