Java tutorial
/** * Copyright 2009-2019 the original author or authors. * * 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.ibatis.parsing; import java.io.InputStream; import java.io.Reader; import java.io.StringReader; import java.util.ArrayList; import java.util.List; import java.util.Properties; import javax.xml.XMLConstants; import javax.xml.namespace.QName; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.xpath.XPath; import javax.xml.xpath.XPathConstants; import javax.xml.xpath.XPathFactory; import org.apache.ibatis.builder.BuilderException; import org.w3c.dom.Document; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import org.xml.sax.EntityResolver; import org.xml.sax.ErrorHandler; import org.xml.sax.InputSource; import org.xml.sax.SAXException; import org.xml.sax.SAXParseException; /** * @author Clinton Begin * @author Kazuki Shimizu */ public class XPathParser { private final Document document; private boolean validation; private EntityResolver entityResolver; private Properties variables; private XPath xpath; public XPathParser(String xml) { commonConstructor(false, null, null); this.document = createDocument(new InputSource(new StringReader(xml))); } public XPathParser(Reader reader) { commonConstructor(false, null, null); this.document = createDocument(new InputSource(reader)); } public XPathParser(InputStream inputStream) { commonConstructor(false, null, null); this.document = createDocument(new InputSource(inputStream)); } public XPathParser(Document document) { commonConstructor(false, null, null); this.document = document; } public XPathParser(String xml, boolean validation) { commonConstructor(validation, null, null); this.document = createDocument(new InputSource(new StringReader(xml))); } public XPathParser(Reader reader, boolean validation) { commonConstructor(validation, null, null); this.document = createDocument(new InputSource(reader)); } public XPathParser(InputStream inputStream, boolean validation) { commonConstructor(validation, null, null); this.document = createDocument(new InputSource(inputStream)); } public XPathParser(Document document, boolean validation) { commonConstructor(validation, null, null); this.document = document; } public XPathParser(String xml, boolean validation, Properties variables) { commonConstructor(validation, variables, null); this.document = createDocument(new InputSource(new StringReader(xml))); } public XPathParser(Reader reader, boolean validation, Properties variables) { commonConstructor(validation, variables, null); this.document = createDocument(new InputSource(reader)); } public XPathParser(InputStream inputStream, boolean validation, Properties variables) { commonConstructor(validation, variables, null); this.document = createDocument(new InputSource(inputStream)); } public XPathParser(Document document, boolean validation, Properties variables) { commonConstructor(validation, variables, null); this.document = document; } public XPathParser(String xml, boolean validation, Properties variables, EntityResolver entityResolver) { commonConstructor(validation, variables, entityResolver); this.document = createDocument(new InputSource(new StringReader(xml))); } public XPathParser(Reader reader, boolean validation, Properties variables, EntityResolver entityResolver) { commonConstructor(validation, variables, entityResolver); this.document = createDocument(new InputSource(reader)); } public XPathParser(InputStream inputStream, boolean validation, Properties variables, EntityResolver entityResolver) { commonConstructor(validation, variables, entityResolver); this.document = createDocument(new InputSource(inputStream)); } public XPathParser(Document document, boolean validation, Properties variables, EntityResolver entityResolver) { commonConstructor(validation, variables, entityResolver); this.document = document; } public void setVariables(Properties variables) { this.variables = variables; } public String evalString(String expression) { return evalString(document, expression); } public String evalString(Object root, String expression) { String result = (String) evaluate(expression, root, XPathConstants.STRING); result = PropertyParser.parse(result, variables); return result; } public Boolean evalBoolean(String expression) { return evalBoolean(document, expression); } public Boolean evalBoolean(Object root, String expression) { return (Boolean) evaluate(expression, root, XPathConstants.BOOLEAN); } public Short evalShort(String expression) { return evalShort(document, expression); } public Short evalShort(Object root, String expression) { return Short.valueOf(evalString(root, expression)); } public Integer evalInteger(String expression) { return evalInteger(document, expression); } public Integer evalInteger(Object root, String expression) { return Integer.valueOf(evalString(root, expression)); } public Long evalLong(String expression) { return evalLong(document, expression); } public Long evalLong(Object root, String expression) { return Long.valueOf(evalString(root, expression)); } public Float evalFloat(String expression) { return evalFloat(document, expression); } public Float evalFloat(Object root, String expression) { return Float.valueOf(evalString(root, expression)); } public Double evalDouble(String expression) { return evalDouble(document, expression); } public Double evalDouble(Object root, String expression) { return (Double) evaluate(expression, root, XPathConstants.NUMBER); } public List<XNode> evalNodes(String expression) { return evalNodes(document, expression); } public List<XNode> evalNodes(Object root, String expression) { List<XNode> xnodes = new ArrayList<>(); NodeList nodes = (NodeList) evaluate(expression, root, XPathConstants.NODESET); for (int i = 0; i < nodes.getLength(); i++) { xnodes.add(new XNode(this, nodes.item(i), variables)); } return xnodes; } public XNode evalNode(String expression) { return evalNode(document, expression); } public XNode evalNode(Object root, String expression) { Node node = (Node) evaluate(expression, root, XPathConstants.NODE); if (node == null) { return null; } return new XNode(this, node, variables); } private Object evaluate(String expression, Object root, QName returnType) { try { return xpath.evaluate(expression, root, returnType); } catch (Exception e) { throw new BuilderException("Error evaluating XPath. Cause: " + e, e); } } private Document createDocument(InputSource inputSource) { // important: this must only be called AFTER common constructor try { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); factory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true); factory.setValidating(validation); factory.setNamespaceAware(false); factory.setIgnoringComments(true); factory.setIgnoringElementContentWhitespace(false); factory.setCoalescing(false); factory.setExpandEntityReferences(true); DocumentBuilder builder = factory.newDocumentBuilder(); builder.setEntityResolver(entityResolver); builder.setErrorHandler(new ErrorHandler() { @Override public void error(SAXParseException exception) throws SAXException { throw exception; } @Override public void fatalError(SAXParseException exception) throws SAXException { throw exception; } @Override public void warning(SAXParseException exception) throws SAXException { // NOP } }); return builder.parse(inputSource); } catch (Exception e) { throw new BuilderException("Error creating document instance. Cause: " + e, e); } } private void commonConstructor(boolean validation, Properties variables, EntityResolver entityResolver) { this.validation = validation; this.entityResolver = entityResolver; this.variables = variables; XPathFactory factory = XPathFactory.newInstance(); this.xpath = factory.newXPath(); } }