/*
* Copyright (c) 2002-2012 Alibaba Group Holding Limited.
* All rights reserved.
*
* 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 com.alibaba.citrus.springext.util;
import static com.alibaba.citrus.util.Assert.*;
import static com.alibaba.citrus.util.CollectionUtil.*;
import static com.alibaba.citrus.util.ObjectUtil.*;
import static com.alibaba.citrus.util.StringUtil.*;
import static org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.*;
import java.util.List;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import com.alibaba.citrus.util.Assert;
import org.dom4j.io.DOMReader;
import org.dom4j.io.SAXWriter;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.ContentHandler;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXException;
import org.xml.sax.ext.LexicalHandler;
/**
* 方便操作dom的工具。
*
* @author Michael Zhou
*/
public class DomUtil {
/** 将W3C element转换成DOM4j element。 */
public static org.dom4j.Element convertElement(Element element) {
Document doc;
try {
doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
} catch (ParserConfigurationException e) {
throw new IllegalArgumentException("Failed to create dom4j document", e);
}
Element clonedElement = (Element) doc.importNode(element, true);
doc.appendChild(clonedElement);
DOMReader reader = new DOMReader();
org.dom4j.Document dom4jDoc = reader.read(doc);
return dom4jDoc.getRootElement();
}
/** 将W3C element转换成SAX事件。 */
public static void convertElement(Element element, ContentHandler contentHandler) throws SAXException {
SAXWriter writer = new SAXWriter(contentHandler);
if (contentHandler instanceof ErrorHandler) {
writer.setErrorHandler((ErrorHandler) contentHandler);
}
if (contentHandler instanceof LexicalHandler) {
writer.setLexicalHandler((LexicalHandler) contentHandler);
}
writer.write(convertElement(element));
}
/** 取得所有子elements。 */
public static List<Element> subElements(Element element) {
return subElements(element, null);
}
/** 取得所有子elements，如果未指定selector，则返回所有elements。 */
public static List<Element> subElements(Element element, ElementSelector selector) {
NodeList nodes = element.getChildNodes();
List<Element> subElements = createArrayList(nodes.getLength());
for (int i = 0; i < nodes.getLength(); i++) {
Node node = nodes.item(i);
if (node instanceof Element) {
Element subElement = (Element) node;
if (selector == null || selector.accept(subElement)) {
subElements.add(subElement);
}
}
}
return subElements;
}
public static Element theOnlySubElement(Element element, ElementSelector selector) {
List<Element> subElements = subElements(element, selector);
switch (subElements.size()) {
case 1:
return subElements.get(0);
case 0:
return null;
default:
fail("too more sub-elements of %s", element.getNodeName());
return null;
}
}
/** Element选择器。 */
public static interface ElementSelector {
boolean accept(Element element);
}
/** 过滤出指定namespace下的elements，或不存在namespace的elements（unqualified）。 */
public static ElementSelector sameNs(Element element) {
String namespaceURI = assertNotNull(element, "element").getNamespaceURI();
return or(ns(namespaceURI), ns(null));
}
/** 过滤出默认namespace，即beans名字空间下的elements。 */
public static ElementSelector beansNs() {
return ns(BEANS_NAMESPACE_URI);
}
/** 匹配任意element。 */
public static ElementSelector any() {
return new ElementSelector() {
public boolean accept(Element element) {
return true;
}
@Override
public String toString() {
return "any";
}
};
}
/** 不匹配任意element。 */
public static ElementSelector none() {
return new ElementSelector() {
public boolean accept(Element element) {
return false;
}
@Override
public String toString() {
return "none";
}
};
}
/** 过滤出指定namespace下的elements。 */
public static ElementSelector ns(String nsUri) {
final String trimmedNsUri = trimToNull(nsUri);
return new ElementSelector() {
public boolean accept(Element element) {
return isEquals(element.getNamespaceURI(), trimmedNsUri);
}
@Override
public String toString() {
return "ns[" + (trimmedNsUri == null ? "no namespace" : trimmedNsUri) + "]";
}
};
}
/** 过滤指定名称的elements。 */
public static ElementSelector name(String name) {
final String trimmedName = assertNotNull(trimToNull(name), "elementName");
return new ElementSelector() {
public boolean accept(Element element) {
String name = element.getNamespaceURI() == null ? element.getNodeName() : element.getLocalName();
return isEquals(name, trimmedName);
}
@Override
public String toString() {
return "name[" + trimmedName + "]";
}
};
}
/** 符合任意一个selector条件，即接受之。 */
public static ElementSelector or(final ElementSelector... selectors) {
return new ElementSelector() {
public boolean accept(Element element) {
if (selectors != null) {
for (ElementSelector selector : selectors) {
if (selector.accept(element)) {
return true;
}
}
return false;
} else {
return true;
}
}
@Override
public String toString() {
return "or" + asList(selectors);
}
};
}
/** 符合所有selector条件，才接受之。 */
public static ElementSelector and(final ElementSelector... selectors) {
return new ElementSelector() {
public boolean accept(Element element) {
if (selectors != null) {
for (ElementSelector selector : selectors) {
if (!selector.accept(element)) {
return false;
}
}
}
return true;
}
@Override
public String toString() {
return "and" + asList(selectors);
}
};
}
/** 不符合selector条件，才接受之。 */
public static ElementSelector not(final ElementSelector selector) {
assertNotNull(selector, "selector");
return new ElementSelector() {
public boolean accept(Element element) {
return !selector.accept(element);
}
@Override
public String toString() {
return "not[" + selector + "]";
}
};
}
/** 抛出异常，通常和or子句配合。 */
public static ElementSelector error() {
return error(null, null);
}
/** 抛出异常，通常和or子句配合。 */
public static ElementSelector error(final Assert.ExceptionType type, final String message) {
return new ElementSelector() {
public boolean accept(Element element) {
assertTrue(false, type, defaultIfEmpty(message, "Unexpected element: " + element.getNodeName()));
return false;
}
@Override
public String toString() {
return "error";
}
};
}
}