- /*
- * Copyright 1999-2004 The Apache Software Foundation
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- package org.apache.commons.jxpath.ri;
-
- import java.io.StringReader;
-
- import org.apache.commons.jxpath.JXPathException;
- import org.apache.commons.jxpath.ri.parser.ParseException;
- import org.apache.commons.jxpath.ri.parser.TokenMgrError;
- import org.apache.commons.jxpath.ri.parser.XPathParser;
-
- /**
- * XPath parser
- *
- * @author Dmitri Plotnikov
- * @version $Revision: 1.8 $ $Date: 2004/02/29 14:17:45 $
- */
- public class Parser {
-
- private static XPathParser parser = new XPathParser(new StringReader(""));
-
- /**
- * Parses the XPath expression. Throws a JXPathException in case
- * of a syntax error.
- */
- public static Object parseExpression(
- String expression,
- Compiler compiler)
- {
- synchronized (parser) {
- parser.setCompiler(compiler);
- Object expr = null;
- try {
- parser.ReInit(new StringReader(expression));
- expr = parser.parseExpression();
- }
- catch (TokenMgrError e) {
- throw new JXPathException(
- "Invalid XPath: '"
- + addEscapes(expression)
- + "'. Invalid symbol '"
- + addEscapes(String.valueOf(e.getCharacter()))
- + "' "
- + describePosition(expression, e.getPosition()));
- }
- catch (ParseException e) {
- throw new JXPathException(
- "Invalid XPath: '"
- + addEscapes(expression)
- + "'. Syntax error "
- + describePosition(
- expression,
- e.currentToken.beginColumn));
- }
- return expr;
- }
- }
-
- private static String describePosition(String expression, int position) {
- if (position <= 0) {
- return "at the beginning of the expression";
- }
- else if (position >= expression.length()) {
- return "- expression incomplete";
- }
- else {
- return "after: '"
- + addEscapes(expression.substring(0, position)) + "'";
- }
- }
-
- private static String addEscapes(String string) {
- // Piggy-back on the code generated by JavaCC
- return TokenMgrError.addEscapes(string);
- }
- }