127 lines
3.7 KiB
Java
127 lines
3.7 KiB
Java
/*
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* Copyright 2008 National Library of Sweden
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package se.kb.xml;
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import java.util.HashMap;
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import java.util.List;
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import java.util.Map;
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import org.dom4j.DocumentHelper;
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import org.dom4j.Element;
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import org.dom4j.Node;
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import org.dom4j.XPath;
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/**
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* Helper class that eases the job of handling XPath queries and
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* getting the different results. It wraps a {@link org.dom4j.Node}
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* and then performs the XPath queries on that.
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*
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* @author Oskar Grenholm, National Library of Sweden
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*/
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public class XPathWrapper {
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private Node node;
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private Map<String, String> namespaces;
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/**
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* Wraps a <code>Node</code> for easier XPath handling.
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*
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* @param node the <code>Node</code> to wrap
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*/
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public XPathWrapper(Node node) {
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this(node, new HashMap<String, String>());
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}
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/**
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* Creates a <code>XPathWrapper</code> that should be aware of all
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* the namespaces in the Map when handling XPath queries.
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*
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* @param node the <code>Node</code> to wrap
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* @param namespaces the namespaces
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*/
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public XPathWrapper(Node node, Map<String, String> namespaces) {
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this.node = node;
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this.namespaces = namespaces;
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}
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/**
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* Adds a namespace that the wrapper should be aware of when performing
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* XPath queries.
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*
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* @param prefix the prefix of the namespace
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* @param uri the uri of the namespace
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*/
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public void addNamespace(String prefix, String uri) {
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namespaces.put(prefix, uri);
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}
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/**
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* Selects a single node that matches the given XPath.
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*
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* @param xpathExpression the xpath
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*
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* @return a single <code>Node</code> or <code>null</code> if no match
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*/
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public Node selectSingleNode(String xpathExpression) {
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XPath xpath = createXPath(xpathExpression);
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return xpath.selectSingleNode(node);
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}
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/**
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* Selects all <code>Nodes</code> that matches the given XPath.
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*
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* @param xpathExpression the xpath
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*
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* @return a list of nodes (can be empty if no matches)
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*/
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@SuppressWarnings("unchecked")
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public List<Node> selectNodes(String xpathExpression) {
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XPath xpath = createXPath(xpathExpression);
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return xpath.selectNodes(node);
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}
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/**
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* Selects a single result that matches the given XPath and
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* then casts it into a <code>Element</code>.
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*
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* @param xpathExpression the xpath
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*
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* @return a single <code>Element</code> or <code>null</code> if no match
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*/
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public Element selectSingleElement(String xpathExpression) {
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return (Element) selectSingleNode(xpathExpression);
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}
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/**
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* Selects the value of the given XPath.
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*
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* @param xpathExpression the xpath
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*
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* @return the value or <code>null</code> if no match
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*/
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public String valueOf(String xpathExpression) {
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XPath xpath = createXPath(xpathExpression);
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return xpath.valueOf(node);
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}
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private XPath createXPath(String xpathExpression) {
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XPath xpath = DocumentHelper.createXPath(xpathExpression);
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xpath.setNamespaceURIs(namespaces);
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return xpath;
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}
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}
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