Java tutorial
/* * * * The Apache Software License, Version 1.1 * * Copyright (c) 1999 The Apache Software Foundation. All rights * reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. The end-user documentation included with the redistribution, if * any, must include the following acknowlegement: * "This product includes software developed by the * Apache Software Foundation (http://www.apache.org/)." * Alternately, this acknowlegement may appear in the software itself, * if and wherever such third-party acknowlegements normally appear. * * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software * Foundation" must not be used to endorse or promote products derived * from this software without prior written permission. For written * permission, please contact apache@apache.org. * * 5. Products derived from this software may not be called "Apache" * nor may "Apache" appear in their names without prior written * permission of the Apache Group. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. */ import java.io.OutputStream; import java.io.OutputStreamWriter; import java.io.PrintWriter; import java.io.StringWriter; import java.io.UnsupportedEncodingException; import java.io.Writer; import java.util.HashMap; import java.util.Iterator; import java.util.Map; import org.w3c.dom.Attr; import org.w3c.dom.Element; import org.w3c.dom.NamedNodeMap; import org.w3c.dom.Node; import org.w3c.dom.NodeList; /** * Traverse a DOM tree in order to print a document that is parsed. * * @author Andy Clark, IBM * @author Thomas.Diesler@jboss.org */ @SuppressWarnings("unchecked") public class DOMWriter { // Print writer private PrintWriter out; // True, if canonical output private boolean canonical; // True, if pretty printing should be used private boolean prettyprint; // True, if the XML declaration should be written private boolean writeXMLDeclaration; // True, if whitespace should be ignored private boolean ignoreWhitespace; // Explicit character set encoding private String charsetName; // indent for the pretty printer private int prettyIndent; // True, if the XML declaration has been written private boolean wroteXMLDeclaration; // The node that started the write private Node rootNode; // True if we want namespace completion private boolean completeNamespaces = true; // The current default namespace private String currentDefaultNamespace; public DOMWriter(Writer w) { this.out = new PrintWriter(w); } public DOMWriter(Writer w, String charsetName) { this.out = new PrintWriter(w); this.charsetName = charsetName; this.writeXMLDeclaration = true; } public DOMWriter(OutputStream stream) { try { this.out = new PrintWriter(new OutputStreamWriter(stream, "UTF-8")); } catch (UnsupportedEncodingException e) { // ignore, UTF-8 should be available } } public DOMWriter(OutputStream stream, String charsetName) { try { this.out = new PrintWriter(new OutputStreamWriter(stream, charsetName)); this.charsetName = charsetName; this.writeXMLDeclaration = true; } catch (UnsupportedEncodingException e) { throw new IllegalArgumentException("Unsupported encoding: " + charsetName); } } /** * Print a node with explicit prettyprinting. * The defaults for all other DOMWriter properties apply. * */ public static String printNode(Node node, boolean prettyprint) { StringWriter strw = new StringWriter(); new DOMWriter(strw).setPrettyprint(prettyprint).print(node); return strw.toString(); } public boolean isCanonical() { return canonical; } /** * Set wheter entities should appear in their canonical form. * The default is false. */ public DOMWriter setCanonical(boolean canonical) { this.canonical = canonical; return this; } public boolean isIgnoreWhitespace() { return ignoreWhitespace; } /** * Set whether whitespace should be ignored. * The default is false. */ public DOMWriter setIgnoreWhitespace(boolean ignoreWhitespace) { this.ignoreWhitespace = ignoreWhitespace; return this; } /** * Set wheter subelements should have their namespaces completed. * Setting this to false may lead to invalid XML fragments. * The default is true. */ public DOMWriter setCompleteNamespaces(boolean complete) { this.completeNamespaces = complete; return this; } public boolean isPrettyprint() { return prettyprint; } /** * Set wheter element should be indented. * The default is false. */ public DOMWriter setPrettyprint(boolean prettyprint) { this.prettyprint = prettyprint; return this; } public boolean isWriteXMLDeclaration() { return writeXMLDeclaration; } /** * Set wheter the XML declaration should be written. * The default is false. */ public DOMWriter setWriteXMLDeclaration(boolean flag) { this.writeXMLDeclaration = flag; return this; } public void print(Node node) { if (prettyprint && ignoreWhitespace) throw new IllegalStateException("Cannot pretty print and ignore whitespace"); rootNode = node; printInternal(node, false); } private void printInternal(Node node, boolean indentEndMarker) { // is there anything to do? if (node == null) { return; } // JBAS-2117 - Don't skip the DOCUMENT_NODE // if (node instanceof Document) node = ((Document)node).getDocumentElement(); if (wroteXMLDeclaration == false && writeXMLDeclaration == true && canonical == false) { out.print("<?xml version='1.0'"); if (charsetName != null) out.print(" encoding='" + charsetName + "'"); out.print("?>"); if (prettyprint) out.println(); wroteXMLDeclaration = true; } int type = node.getNodeType(); boolean hasChildNodes = node.getChildNodes().getLength() > 0; String nodeName = node.getNodeName(); switch (type) { // print document case Node.DOCUMENT_NODE: { NodeList children = node.getChildNodes(); for (int iChild = 0; iChild < children.getLength(); iChild++) { printInternal(children.item(iChild), false); } out.flush(); break; } // print element with attributes case Node.ELEMENT_NODE: { Element element = (Element) node; if (prettyprint) { for (int i = 0; i < prettyIndent; i++) { out.print(' '); } prettyIndent++; } out.print('<'); out.print(nodeName); Map nsMap = new HashMap(); String elPrefix = node.getPrefix(); String elNamespaceURI = node.getNamespaceURI(); if (elPrefix != null) { String nsURI = getNamespaceURI(elPrefix, element, rootNode); nsMap.put(elPrefix, nsURI); } Attr attrs[] = sortAttributes(node.getAttributes()); for (int i = 0; i < attrs.length; i++) { Attr attr = attrs[i]; String atPrefix = attr.getPrefix(); String atName = attr.getNodeName(); String atValue = normalize(attr.getNodeValue(), canonical); if (atName.equals("xmlns")) currentDefaultNamespace = atValue; if (atPrefix != null && !atPrefix.equals("xmlns") && !atPrefix.equals("xml")) { String nsURI = getNamespaceURI(atPrefix, element, rootNode); nsMap.put(atPrefix, nsURI); // xsi:type='ns1:SubType', xsi:type='xsd:string' if (atName.equals(atPrefix + ":type") && atValue.indexOf(":") > 0) { // xsi defined on the envelope if (nsURI == null) nsURI = getNamespaceURI(atPrefix, element, null); if ("http://www.w3.org/2001/XMLSchema-instance".equals(nsURI)) { String typePrefix = atValue.substring(0, atValue.indexOf(":")); String typeURI = getNamespaceURI(typePrefix, element, rootNode); nsMap.put(typePrefix, typeURI); } } } out.print(" " + atName + "='" + atValue + "'"); } // Add namespace declaration for prefixes // that are defined further up the tree if (completeNamespaces) { Iterator itPrefix = nsMap.keySet().iterator(); while (itPrefix.hasNext()) { String prefix = (String) itPrefix.next(); String nsURI = (String) nsMap.get(prefix); if (nsURI == null) { nsURI = getNamespaceURI(prefix, element, null); out.print(" xmlns:" + prefix + "='" + nsURI + "'"); } } } // The SAX ContentHandler will by default not add the namespace declaration // <Hello xmlns='http://somens'>World</Hello> if (elPrefix == null && elNamespaceURI != null) { String defaultNamespace = element.getAttribute("xmlns"); if (defaultNamespace.length() == 0 && !elNamespaceURI.equals(currentDefaultNamespace)) { out.print(" xmlns='" + elNamespaceURI + "'"); currentDefaultNamespace = elNamespaceURI; } } if (hasChildNodes) { out.print('>'); } // Find out if the end marker is indented indentEndMarker = isEndMarkerIndented(node); if (indentEndMarker) { out.print('\n'); } NodeList childNodes = node.getChildNodes(); int len = childNodes.getLength(); for (int i = 0; i < len; i++) { Node childNode = childNodes.item(i); printInternal(childNode, false); } break; } // handle entity reference nodes case Node.ENTITY_REFERENCE_NODE: { if (canonical) { NodeList children = node.getChildNodes(); if (children != null) { int len = children.getLength(); for (int i = 0; i < len; i++) { printInternal(children.item(i), false); } } } else { out.print('&'); out.print(nodeName); out.print(';'); } break; } // print cdata sections case Node.CDATA_SECTION_NODE: { if (canonical) { out.print(normalize(node.getNodeValue(), canonical)); } else { out.print("<![CDATA["); out.print(node.getNodeValue()); out.print("]]>"); } break; } // print text case Node.TEXT_NODE: { String text = normalize(node.getNodeValue(), canonical); if (text.trim().length() > 0) { out.print(text); } else if (prettyprint == false && ignoreWhitespace == false) { out.print(text); } break; } // print processing instruction case Node.PROCESSING_INSTRUCTION_NODE: { out.print("<?"); out.print(nodeName); String data = node.getNodeValue(); if (data != null && data.length() > 0) { out.print(' '); out.print(data); } out.print("?>"); break; } // print comment case Node.COMMENT_NODE: { for (int i = 0; i < prettyIndent; i++) { out.print(' '); } out.print("<!--"); String data = node.getNodeValue(); if (data != null) { out.print(data); } out.print("-->"); if (prettyprint) { out.print('\n'); } break; } } if (type == Node.ELEMENT_NODE) { if (prettyprint) prettyIndent--; if (hasChildNodes == false) { out.print("/>"); } else { if (indentEndMarker) { for (int i = 0; i < prettyIndent; i++) { out.print(' '); } } out.print("</"); out.print(nodeName); out.print('>'); } if (prettyIndent > 0) { out.print('\n'); } } out.flush(); } private String getNamespaceURI(String prefix, Element element, Node stopNode) { Node parent = element.getParentNode(); String nsURI = element.getAttribute("xmlns:" + prefix); if (nsURI.length() == 0 && element != stopNode && parent instanceof Element) return getNamespaceURI(prefix, (Element) parent, stopNode); return (nsURI.length() > 0 ? nsURI : null); } private boolean isEndMarkerIndented(Node node) { if (prettyprint) { NodeList childNodes = node.getChildNodes(); int len = childNodes.getLength(); for (int i = 0; i < len; i++) { Node children = childNodes.item(i); if (children.getNodeType() == Node.ELEMENT_NODE) { return true; } } } return false; } /** Returns a sorted list of attributes. */ private Attr[] sortAttributes(NamedNodeMap attrs) { int len = (attrs != null) ? attrs.getLength() : 0; Attr array[] = new Attr[len]; for (int i = 0; i < len; i++) { array[i] = (Attr) attrs.item(i); } for (int i = 0; i < len - 1; i++) { String name = array[i].getNodeName(); int index = i; for (int j = i + 1; j < len; j++) { String curName = array[j].getNodeName(); if (curName.compareTo(name) < 0) { name = curName; index = j; } } if (index != i) { Attr temp = array[i]; array[i] = array[index]; array[index] = temp; } } return (array); } /** Normalizes the given string. */ public static String normalize(String s, boolean canonical) { StringBuffer str = new StringBuffer(); int len = (s != null) ? s.length() : 0; for (int i = 0; i < len; i++) { char ch = s.charAt(i); switch (ch) { case '<': { str.append("<"); break; } case '>': { str.append(">"); break; } case '&': { str.append("&"); break; } case '"': { str.append("""); break; } case '\'': { str.append("'"); break; } case '\r': case '\n': { if (canonical) { str.append("&#"); str.append(Integer.toString(ch)); str.append(';'); break; } // else, default append char } default: { str.append(ch); } } } return (str.toString()); } }