public boolean addInvocationTarget( String name, 
					RPCInvocationTarget target,
					boolean useAsDefaultTarget
					) 
	throws NullPointerException {

	if( name == null )
	    throw new NullPointerException( "Cannot add invocation targets with null name." );
	if( target == null )
	    throw new NullPointerException( "Cannot add null invocation targets." );

	boolean existed = this.targetMap.containsKey( name );

	this.targetMap.put( name, target );
	if( useAsDefaultTarget )
	    this.defaultInvocationTargetName = name;
	
	return existed;
    }