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/*
 * #%L
 * The AIBench Shell Plugin
 * %%
 * Copyright (C) 2006 - 2017 Daniel Glez-Peña and Florentino Fdez-Riverola
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Lesser Public License for more details.
 * 
 * You should have received a copy of the GNU General Lesser Public
 * License along with this program.  If not, see
 * .
 * #L%
 */
/*****************************************************************************
 *                                                                           *
 *  This file is part of the BeanShell Java Scripting distribution.          *
 *  Documentation and updates may be found at http://www.beanshell.org/      *
 *                                                                           *
 *  Sun Public License Notice:                                               *
 *                                                                           *
 *  The contents of this file are subject to the Sun Public License Version  *
 *  1.0 (the "License"); you may not use this file except in compliance with *
 *  the License. A copy of the License is available at http://www.sun.com    * 
 *                                                                           *
 *  The Original Code is BeanShell. The Initial Developer of the Original    *
 *  Code is Pat Niemeyer. Portions created by Pat Niemeyer are Copyright     *
 *  (C) 2000.  All Rights Reserved.                                          *
 *                                                                           *
 *  GNU Public License Notice:                                               *
 *                                                                           *
 *  Alternatively, the contents of this file may be used under the terms of  *
 *  the GNU Lesser General Public License (the "LGPL"), in which case the    *
 *  provisions of LGPL are applicable instead of those above. If you wish to *
 *  allow use of your version of this file only under the  terms of the LGPL *
 *  and not to allow others to use your version of this file under the SPL,  *
 *  indicate your decision by deleting the provisions above and replace      *
 *  them with the notice and other provisions required by the LGPL.  If you  *
 *  do not delete the provisions above, a recipient may use your version of  *
 *  this file under either the SPL or the LGPL.                              *
 *                                                                           *
 *  Patrick Niemeyer ([email protected])                                           *
 *  Author of Learning Java, O'Reilly & Associates                           *
 *  http://www.pat.net/~pat/                                                 *
 *                                                                           *
 *****************************************************************************/

package bsh;

/**
 * 
 * EvalError indicates that we cannot continue evaluating the script or the
 * script has thrown an exception.
 * 
 * 
 * 
 * EvalError may be thrown for a script syntax error, an evaluation error such
 * as referring to an undefined variable, an internal error.
 * 
 * 
 * @see TargetError
 */
public class EvalError extends Exception {
	private static final long serialVersionUID = 1L;

	SimpleNode node;

	// Note: no way to mutate the Throwable message, must maintain our own
	String message;

	CallStack callstack;

	public EvalError(String s, SimpleNode node, CallStack callstack) {
		setMessage(s);
		this.node = node;
		// freeze the callstack for the stack trace.
		if (callstack != null)
			this.callstack = callstack.copy();
	}

	/**
	 * Print the error with line number and stack trace.
	 */
	public String toString() {
		String trace;
		if (node != null)
			trace = " : at Line: " + node.getLineNumber() + " : in file: " + node.getSourceFile() + " : " + node.getText();
		else
			// Users should not normally see this.
			trace = ": ";

		if (callstack != null)
			trace = trace + "\n" + getScriptStackTrace();

		return getMessage() + trace;
	}

	/**
	 * Re-throw the error, prepending the specified message.
	 * 
	 * @param msg the message to be prepended.
	 * @throws EvalError this method always throws this error.
	 */
	public void reThrow(String msg) throws EvalError {
		prependMessage(msg);
		throw this;
	}

	/**
	 * The error has trace info associated with it. i.e. It has an AST node that
	 * can print its location and source text.
	 * 
	 * @return the associated node.
	 */
	SimpleNode getNode() {
		return node;
	}

	void setNode(SimpleNode node) {
		this.node = node;
	}

	public String getErrorText() {
		if (node != null)
			return node.getText();
		else
			return "";
	}

	public int getErrorLineNumber() {
		if (node != null)
			return node.getLineNumber();
		else
			return -1;
	}

	public String getErrorSourceFile() {
		if (node != null)
			return node.getSourceFile();
		else
			return "";
	}

	public String getScriptStackTrace() {
		if (callstack == null)
			return "";

		String trace = "";
		CallStack stack = callstack.copy();
		while (stack.depth() > 0) {
			NameSpace ns = stack.pop();
			SimpleNode node = ns.getNode();
			if (ns.isMethod) {
				trace = trace + "\nCalled from method: " + ns.getName();
				if (node != null)
					trace += " : at Line: " + node.getLineNumber() + " : in file: " + node.getSourceFile() + " : " + node.getText();
			}
		}

		return trace;
	}

	/**
	 * @see #toString() for a full display of the information
	 */
	public String getMessage() {
		return message;
	}

	public void setMessage(String s) {
		message = s;
	}

	/**
	 * Prepend the message if it is non-null.
	 * 
	 * @param s
	 *            the message to be prepended.
	 */
	protected void prependMessage(String s) {
		if (s == null)
			return;

		if (message == null)
			message = s;
		else
			message = s + " : " + message;
	}

}