/jEdit/tags/jedit-4-2-pre14/bsh/UtilEvalError.java

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 *  Patrick Niemeyer (pat@pat.net)                                           *
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 *  http://www.pat.net/~pat/                                                 *
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 *****************************************************************************/


package bsh;

/**
	UtilEvalError is an error corresponding to an EvalError but thrown by a 
	utility or other class that does not have the caller context (Node) 
	available to it.  A normal EvalError must supply the caller Node in order 
	for error messages to be pinned to the correct line and location in the 
	script.  UtilEvalError is a checked exception that is *not* a subtype of 
	EvalError, but instead must be caught and rethrown as an EvalError by 
	the a nearest location with context.  The method toEvalError( Node ) 
	should be used to throw the EvalError, supplying the node.
	<p>

	To summarize: Utilities throw UtilEvalError.  ASTs throw EvalError.
	ASTs catch UtilEvalError and rethrow it as EvalError using 
	toEvalError( Node ).  
	<p>

	Philosophically, EvalError and UtilEvalError corrospond to 
	RuntimeException.  However they are constrained in this way in order to 
	add the context for error reporting.

	@see UtilTargetError
*/
public class UtilEvalError extends Exception 
{
	protected UtilEvalError() {
	}

	public UtilEvalError( String s ) {
		super(s);
	}

	/**
		Re-throw as an eval error, prefixing msg to the message and specifying
		the node.  If a node already exists the addNode is ignored.
		@see #setNode( bsh.SimpleNode )
		<p>
		@param msg may be null for no additional message.
	*/
	public EvalError toEvalError( 
		String msg, SimpleNode node, CallStack callstack  ) 
	{
		if ( Interpreter.DEBUG )
			printStackTrace();

		if ( msg == null )
			msg = "";
		else
			msg = msg + ": ";
		return new EvalError( msg+getMessage(), node, callstack );
	}

	public EvalError toEvalError ( SimpleNode node, CallStack callstack ) 
	{
		return toEvalError( null, node, callstack );
	}

}