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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.jetspeed.util;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
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;
import org.w3c.dom.Text;
/**
* Writes a DOM tree to a given Writer.
* warning: this utility currently does not declare XML Namespaces.
* Utility class used by {@link org.apache.jetspeed.util.DOMUtils}.
*/
public class DOMElementWriter {
private static final int HEX = 16;
/** prefix for generated prefixes */
private static final String NS = "ns";
/** xml declaration is on by default */
private boolean xmlDeclaration = true;
/**
* XML Namespaces are ignored by default.
*/
private XmlNamespacePolicy namespacePolicy = XmlNamespacePolicy.IGNORE;
/**
* Map (URI to prefix) of known namespaces.
*/
private HashMap nsPrefixMap = new HashMap();
/**
* Number of generated prefix to use next.
*/
private int nextPrefix = 0;
/**
* Map (Element to URI) of namespaces defined on a given element.
*/
private HashMap nsURIByElement = new HashMap();
/**
* Whether namespaces should be ignored for elements and attributes.
*/
public static class XmlNamespacePolicy {
private boolean qualifyElements;
private boolean qualifyAttributes;
/**
* Ignores namespaces for elements and attributes, the default.
*/
public static final XmlNamespacePolicy IGNORE =
new XmlNamespacePolicy(false, false);
/**
* Ignores namespaces for attributes.
*/
public static final XmlNamespacePolicy ONLY_QUALIFY_ELEMENTS =
new XmlNamespacePolicy(true, false);
/**
* Qualifies namespaces for elements and attributes.
*/
public static final XmlNamespacePolicy QUALIFY_ALL =
new XmlNamespacePolicy(true, true);
/**
* @param qualifyElements whether to qualify elements
* @param qualifyAttributes whether to qualify elements
*/
public XmlNamespacePolicy(boolean qualifyElements,
boolean qualifyAttributes) {
this.qualifyElements = qualifyElements;
this.qualifyAttributes = qualifyAttributes;
}
}
/**
* Create an element writer.
* The ?xml? declaration will be included, namespaces ignored.
*/
public DOMElementWriter() {
}
/**
* Create an element writer
* XML namespaces will be ignored.
* @param xmlDeclaration flag to indicate whether the ?xml? declaration
* should be included.
*/
public DOMElementWriter(boolean xmlDeclaration) {
this(xmlDeclaration, XmlNamespacePolicy.IGNORE);
}
/**
* Create an element writer
* XML namespaces will be ignored.
* @param xmlDeclaration flag to indicate whether the ?xml? declaration
* should be included.
* @param namespacePolicy the policy to use.
*/
public DOMElementWriter(boolean xmlDeclaration,
XmlNamespacePolicy namespacePolicy) {
this.xmlDeclaration = xmlDeclaration;
this.namespacePolicy = namespacePolicy;
}
private static String lSep = System.getProperty("line.separator");
// CheckStyle:VisibilityModifier OFF - bc
/**
* Don't try to be too smart but at least recognize the predefined
* entities.
*/
protected String[] knownEntities = {"gt", "amp", "lt", "apos", "quot"};
// CheckStyle:VisibilityModifier ON
/**
* Writes a DOM tree to a stream in UTF8 encoding. Note that
* it prepends the <?xml version='1.0' encoding='UTF-8'?> if
* the xmlDeclaration field is true.
* The indent number is set to 0 and a 2-space indent.
* @param root the root element of the DOM tree.
* @param out the outputstream to write to.
* @throws IOException if an error happens while writing to the stream.
*/
public void write(Element root, OutputStream out) throws IOException {
Writer wri = new OutputStreamWriter(out, "UTF8");
writeXMLDeclaration(wri);
write(root, wri, 0, " ");
wri.flush();
}
/**
* Writes the XML declaration if xmlDeclaration is true.
* @param wri the writer to write to.
* @throws IOException if there is an error.
*/
public void writeXMLDeclaration(Writer wri) throws IOException {
if (xmlDeclaration) {
wri.write("\n");
}
}
/**
* Writes a DOM tree to a stream.
*
* @param element the Root DOM element of the tree
* @param out where to send the output
* @param indent number of
* @param indentWith string that should be used to indent the
* corresponding tag.
* @throws IOException if an error happens while writing to the stream.
*/
public void write(Element element, Writer out, int indent,
String indentWith)
throws IOException {
// Write child elements and text
NodeList children = element.getChildNodes();
boolean hasChildren = (children.getLength() > 0);
boolean hasChildElements = false;
openElement(element, out, indent, indentWith, hasChildren);
if (hasChildren) {
for (int i = 0; i < children.getLength(); i++) {
Node child = children.item(i);
switch (child.getNodeType()) {
case Node.ELEMENT_NODE:
hasChildElements = true;
if (i == 0) {
out.write(lSep);
}
write((Element) child, out, indent + 1, indentWith);
break;
case Node.TEXT_NODE:
out.write(encode(child.getNodeValue()));
break;
case Node.COMMENT_NODE:
out.write("");
break;
case Node.CDATA_SECTION_NODE:
out.write("");
break;
case Node.ENTITY_REFERENCE_NODE:
out.write('&');
out.write(child.getNodeName());
out.write(';');
break;
case Node.PROCESSING_INSTRUCTION_NODE:
out.write(" 0) {
out.write(' ');
out.write(data);
}
out.write("?>");
break;
default:
// Do nothing
}
}
closeElement(element, out, indent, indentWith, hasChildElements);
}
}
/**
* Writes the opening tag - including all attributes -
* corresponding to a DOM element.
*
* @param element the DOM element to write
* @param out where to send the output
* @param indent number of
* @param indentWith string that should be used to indent the
* corresponding tag.
* @throws IOException if an error happens while writing to the stream.
*/
public void openElement(Element element, Writer out, int indent,
String indentWith)
throws IOException {
openElement(element, out, indent, indentWith, true);
}
/**
* Writes the opening tag - including all attributes -
* corresponding to a DOM element.
*
* @param element the DOM element to write
* @param out where to send the output
* @param indent number of
* @param indentWith string that should be used to indent the
* corresponding tag.
* @param hasChildren whether this element has children.
* @throws IOException if an error happens while writing to the stream.
*/
public void openElement(Element element, Writer out, int indent,
String indentWith, boolean hasChildren)
throws IOException {
// Write indent characters
for (int i = 0; i < indent; i++) {
out.write(indentWith);
}
// Write element
out.write("<");
if (namespacePolicy.qualifyElements) {
String uri = getNamespaceURI(element);
String prefix = (String) nsPrefixMap.get(uri);
if (prefix == null) {
if (nsPrefixMap.isEmpty()) {
// steal default namespace
prefix = "";
} else {
prefix = NS + (nextPrefix++);
}
nsPrefixMap.put(uri, prefix);
addNSDefinition(element, uri);
}
if (!"".equals(prefix)) {
out.write(prefix);
out.write(":");
}
}
out.write(element.getTagName());
// Write attributes
NamedNodeMap attrs = element.getAttributes();
for (int i = 0; i < attrs.getLength(); i++) {
Attr attr = (Attr) attrs.item(i);
out.write(" ");
if (namespacePolicy.qualifyAttributes) {
String uri = getNamespaceURI(attr);
String prefix = (String) nsPrefixMap.get(uri);
if (prefix == null) {
prefix = NS + (nextPrefix++);
nsPrefixMap.put(uri, prefix);
addNSDefinition(element, uri);
}
out.write(prefix);
out.write(":");
}
out.write(attr.getName());
out.write("=\"");
out.write(encode(attr.getValue()));
out.write("\"");
}
// write namespace declarations
ArrayList al = (ArrayList) nsURIByElement.get(element);
if (al != null) {
Iterator iter = al.iterator();
while (iter.hasNext()) {
String uri = (String) iter.next();
String prefix = (String) nsPrefixMap.get(uri);
out.write(" xmlns");
if (!"".equals(prefix)) {
out.write(":");
out.write(prefix);
}
out.write("=\"");
out.write(uri);
out.write("\"");
}
}
if (hasChildren) {
out.write(">");
} else {
removeNSDefinitions(element);
out.write(" />");
out.write(lSep);
out.flush();
}
}
/**
* Writes a DOM tree to a stream.
*
* @param element the Root DOM element of the tree
* @param out where to send the output
* @param indent number of
* @param indentWith string that should be used to indent the
* corresponding tag.
* @param hasChildren if true indent.
* @throws IOException if an error happens while writing to the stream.
*/
public void closeElement(Element element, Writer out, int indent,
String indentWith, boolean hasChildren)
throws IOException {
// If we had child elements, we need to indent before we close
// the element, otherwise we're on the same line and don't need
// to indent
if (hasChildren) {
for (int i = 0; i < indent; i++) {
out.write(indentWith);
}
}
// Write element close
out.write("");
out.write(lSep);
out.flush();
}
/**
* Escape <, > & ', " as their entities and
* drop characters that are illegal in XML documents.
* @param value the string to encode.
* @return the encoded string.
*/
public String encode(String value) {
StringBuffer sb = new StringBuffer();
int len = value.length();
for (int i = 0; i < len; i++) {
char c = value.charAt(i);
switch (c) {
case '<':
sb.append("<");
break;
case '>':
sb.append(">");
break;
case '\'':
sb.append("'");
break;
case '\"':
sb.append(""");
break;
case '&':
int nextSemi = value.indexOf(";", i);
if (nextSemi < 0
|| !isReference(value.substring(i, nextSemi + 1))) {
sb.append("&");
} else {
sb.append('&');
}
break;
default:
if (isLegalCharacter(c)) {
sb.append(c);
}
break;
}
}
return sb.substring(0);
}
/**
* Drop characters that are illegal in XML documents.
*
* Also ensure that we are not including an ]]>
* marker by replacing that sequence with
* ]]>.
*
* See XML 1.0 2.2
* http://www.w3.org/TR/1998/REC-xml-19980210#charsets and
* 2.7 http://www.w3.org/TR/1998/REC-xml-19980210#sec-cdata-sect.
* @param value the value to be encoded.
* @return the encoded value.
*/
public String encodedata(final String value) {
StringBuffer sb = new StringBuffer();
int len = value.length();
for (int i = 0; i < len; ++i) {
char c = value.charAt(i);
if (isLegalCharacter(c)) {
sb.append(c);
}
}
String result = sb.substring(0);
int cdEnd = result.indexOf("]]>");
while (cdEnd != -1) {
sb.setLength(cdEnd);
// CheckStyle:MagicNumber OFF
sb.append("]]>")
.append(result.substring(cdEnd + 3));
// CheckStyle:MagicNumber ON
result = sb.substring(0);
cdEnd = result.indexOf("]]>");
}
return result;
}
/**
* Is the given argument a character or entity reference?
* @param ent the value to be checked.
* @return true if it is an entity.
*/
public boolean isReference(String ent) {
if (!(ent.charAt(0) == '&') || !ent.endsWith(";")) {
return false;
}
if (ent.charAt(1) == '#') {
if (ent.charAt(2) == 'x') {
try {
// CheckStyle:MagicNumber OFF
Integer.parseInt(ent.substring(3, ent.length() - 1), HEX);
// CheckStyle:MagicNumber ON
return true;
} catch (NumberFormatException nfe) {
return false;
}
} else {
try {
Integer.parseInt(ent.substring(2, ent.length() - 1));
return true;
} catch (NumberFormatException nfe) {
return false;
}
}
}
String name = ent.substring(1, ent.length() - 1);
for (int i = 0; i < knownEntities.length; i++) {
if (name.equals(knownEntities[i])) {
return true;
}
}
return false;
}
/**
* Is the given character allowed inside an XML document?
*
* See XML 1.0 2.2
* http://www.w3.org/TR/1998/REC-xml-19980210#charsets.
* @param c the character to test.
* @return true if the character is allowed.
*/
public boolean isLegalCharacter(char c) {
// CheckStyle:MagicNumber OFF
if (c == 0x9 || c == 0xA || c == 0xD) {
return true;
} else if (c < 0x20) {
return false;
} else if (c <= 0xD7FF) {
return true;
} else if (c < 0xE000) {
return false;
} else if (c <= 0xFFFD) {
return true;
}
// CheckStyle:MagicNumber ON
return false;
}
private void removeNSDefinitions(Element element) {
ArrayList al = (ArrayList) nsURIByElement.get(element);
if (al != null) {
Iterator iter = al.iterator();
while (iter.hasNext()) {
nsPrefixMap.remove(iter.next());
}
nsURIByElement.remove(element);
}
}
private void addNSDefinition(Element element, String uri) {
ArrayList al = (ArrayList) nsURIByElement.get(element);
if (al == null) {
al = new ArrayList();
nsURIByElement.put(element, al);
}
al.add(uri);
}
private static String getNamespaceURI(Node n) {
String uri = n.getNamespaceURI();
if (uri == null) {
// FIXME: Is "No Namespace is Empty Namespace" really OK?
uri = "";
}
return uri;
}
}