Mega Code Archive
Traverse a DOM tree in order to print a document that is parsed
<![CDATA[
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// $Id: DOMWriter.java 2891 2008-07-31 16:03:02Z thomas.diesler@jboss.com $
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());
}
}
]]>