Here you can find the source of isValidFilter(String xPathString)
public static boolean isValidFilter(String xPathString)
//package com.java2s; /**/*from w w w. j a va2s .c om*/ * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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. */ import javax.xml.xpath.XPath; import javax.xml.xpath.XPathExpressionException; import javax.xml.xpath.XPathFactory; public class Main { private static XPathFactory xPathFactory = XPathFactory.newInstance(); public static boolean isValidFilter(String xPathString) { if (xPathString == null) { return true; } try { XPath xPath = xPathFactory.newXPath(); xPath.compile(xPathString); return true; } catch (XPathExpressionException ex) { return false; } } }