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Groovy: A powerful, dynamic language for the JVM
/*
* 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 groovy.util;
import groovy.xml.QName;
import org.codehaus.groovy.runtime.InvokerHelper;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* Prints a groovy.util.Node (as used with XmlParser) including all children in XML format.
* Typical usage:
*
* def xml = '<html><head><title>Title</title></head><body><h1>Header</h1></body></html>'
* def root = new XmlParser().parseText(xml)
* new XmlNodePrinter(preserveWhitespace:true).print(root.body[0])
*
* which when run produces this on stdout (or use your own PrintWriter to direct elsewhere):
*
* <body>
* <h1>Header</h1>
* </body>
*
*
* @author Christian Stein
* @see groovy.util.NodePrinter
* @see groovy.xml.XmlUtil#serialize(Node)
*/
public class XmlNodePrinter {
protected final IndentPrinter out;
private String quote;
private boolean namespaceAware = true;
private boolean preserveWhitespace = false;
private boolean expandEmptyElements = false;
public XmlNodePrinter(PrintWriter out) {
this(out, " ");
}
public XmlNodePrinter(PrintWriter out, String indent) {
this(out, indent, "\"");
}
public XmlNodePrinter(PrintWriter out, String indent, String quote) {
this(new IndentPrinter(out, indent), quote);
}
public XmlNodePrinter(IndentPrinter out) {
this(out, "\"");
}
public XmlNodePrinter(IndentPrinter out, String quote) {
if (out == null) {
throw new IllegalArgumentException("Argument 'IndentPrinter out' must not be null!");
}
this.out = out;
this.quote = quote;
}
public XmlNodePrinter() {
this(new PrintWriter(new OutputStreamWriter(System.out)));
}
public void print(Node node) {
print(node, new NamespaceContext());
}
/**
* Check if namespace handling is enabled.
* Defaults to true.
*
* @return true if namespace handling is enabled
*/
public boolean isNamespaceAware() {
return namespaceAware;
}
/**
* Enable and/or disable namespace handling.
*
* @param namespaceAware the new desired value
*/
public void setNamespaceAware(boolean namespaceAware) {
this.namespaceAware = namespaceAware;
}
/**
* Check if whitespace preservation is enabled.
* Defaults to false.
*
* @return true if whitespaces are honoured when printing simple text nodes
*/
public boolean isPreserveWhitespace() {
return preserveWhitespace;
}
/**
* Enable and/or disable preservation of whitespace.
*
* @param preserveWhitespace the new desired value
*/
public void setPreserveWhitespace(boolean preserveWhitespace) {
this.preserveWhitespace = preserveWhitespace;
}
/**
* Get Quote to use when printing attributes.
*
* @return the quote character
*/
public String getQuote() {
return quote;
}
/**
* Set Quote to use when printing attributes.
*
* @param quote the quote character
*/
public void setQuote(String quote) {
this.quote = quote;
}
/**
* Whether empty elements are expanded from <tagName/> to <tagName></tagName>.
*
* @return true, if empty elements will be represented by an opening tag
* followed immediately by a closing tag.
*/
public boolean isExpandEmptyElements() {
return expandEmptyElements;
}
/**
* Whether empty elements are expanded from <tagName/> to <tagName></tagName>.
*
* @param expandEmptyElements if true, empty
* elements will be represented by an opening tag
* followed immediately by a closing tag.
* Defaults to false.
*/
public void setExpandEmptyElements(boolean expandEmptyElements) {
this.expandEmptyElements = expandEmptyElements;
}
protected void print(Node node, NamespaceContext ctx) {
/*
* Handle empty elements like '
', '![]()
or '
.
*/
if (isEmptyElement(node)) {
printLineBegin();
out.print("<");
out.print(getName(node));
if (ctx != null) {
printNamespace(node, ctx);
}
printNameAttributes(node.attributes(), ctx);
if (expandEmptyElements) {
out.print(">");
} else {
out.print("/>");
}
printLineEnd();
out.flush();
return;
}
/*
* Hook for extra processing, e.g. GSP tag element!
*/
if (printSpecialNode(node)) {
out.flush();
return;
}
/*
* Handle normal element like ... .
*/
Object value = node.value();
if (value instanceof List) {
printName(node, ctx, true, isListOfSimple((List) value));
printList((List) value, ctx);
printName(node, ctx, false, isListOfSimple((List) value));
out.flush();
return;
}
// treat as simple type - probably a String
printName(node, ctx, true, preserveWhitespace);
printSimpleItemWithIndent(value);
printName(node, ctx, false, preserveWhitespace);
out.flush();
}
private boolean isListOfSimple(List value) {
for (Object p : value) {
if (p instanceof Node) return false;
}
return preserveWhitespace;
}
protected void printLineBegin() {
out.printIndent();
}
protected void printLineEnd() {
printLineEnd(null);
}
protected void printLineEnd(String comment) {
if (comment != null) {
out.print(" ");
}
out.println();
out.flush();
}
protected void printList(List list, NamespaceContext ctx) {
out.incrementIndent();
for (Object value : list) {
NamespaceContext context = new NamespaceContext(ctx);
/*
* If the current value is a node, recurse into that node.
*/
if (value instanceof Node) {
print((Node) value, context);
continue;
}
printSimpleItem(value);
}
out.decrementIndent();
}
protected void printSimpleItem(Object value) {
if (!preserveWhitespace) printLineBegin();
printEscaped(InvokerHelper.toString(value), false);
if (!preserveWhitespace) printLineEnd();
}
protected void printName(Node node, NamespaceContext ctx, boolean begin, boolean preserve) {
if (node == null) {
throw new NullPointerException("Node must not be null.");
}
Object name = node.name();
if (name == null) {
throw new NullPointerException("Name must not be null.");
}
if (!preserve || begin) printLineBegin();
out.print("<");
if (!begin) {
out.print("/");
}
out.print(getName(node));
if (ctx != null) {
printNamespace(node, ctx);
}
if (begin) {
printNameAttributes(node.attributes(), ctx);
}
out.print(">");
if (!preserve || !begin) printLineEnd();
}
protected boolean printSpecialNode(Node node) {
return false;
}
protected void printNamespace(Object object, NamespaceContext ctx) {
if (namespaceAware) {
if (object instanceof Node) {
printNamespace(((Node) object).name(), ctx);
} else if (object instanceof QName) {
QName qname = (QName) object;
String namespaceUri = qname.getNamespaceURI();
if (namespaceUri != null) {
String prefix = qname.getPrefix();
if (!ctx.isPrefixRegistered(prefix, namespaceUri)) {
ctx.registerNamespacePrefix(prefix, namespaceUri);
out.print(" ");
out.print("xmlns");
if (prefix.length() > 0) {
out.print(":");
out.print(prefix);
}
out.print("=" + quote);
out.print(namespaceUri);
out.print(quote);
}
}
}
}
}
protected void printNameAttributes(Map attributes, NamespaceContext ctx) {
if (attributes == null || attributes.isEmpty()) {
return;
}
for (Object p : attributes.entrySet()) {
Map.Entry entry = (Map.Entry) p;
out.print(" ");
out.print(getName(entry.getKey()));
out.print("=");
Object value = entry.getValue();
out.print(quote);
if (value instanceof String) {
printEscaped((String) value, true);
} else {
printEscaped(InvokerHelper.toString(value), true);
}
out.print(quote);
printNamespace(entry.getKey(), ctx);
}
}
private static boolean isEmptyElement(Node node) {
if (node == null) {
throw new IllegalArgumentException("Node must not be null!");
}
if (!node.children().isEmpty()) {
return false;
}
return node.text().length() == 0;
}
private String getName(Object object) {
if (object instanceof String) {
return (String) object;
} else if (object instanceof QName) {
QName qname = (QName) object;
if (!namespaceAware) {
return qname.getLocalPart();
}
return qname.getQualifiedName();
} else if (object instanceof Node) {
Object name = ((Node) object).name();
return getName(name);
}
return object.toString();
}
private void printSimpleItemWithIndent(Object value) {
if (!preserveWhitespace) out.incrementIndent();
printSimpleItem(value);
if (!preserveWhitespace) out.decrementIndent();
}
// For ' and " we only escape if needed. As far as XML is concerned,
// we could always escape if we wanted to.
private void printEscaped(String s, boolean isAttributeValue) {
for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
switch (c) {
case '<':
out.print("<");
break;
case '>':
out.print(">");
break;
case '&':
out.print("&");
break;
case '\'':
if (isAttributeValue && quote.equals("'"))
out.print("'");
else
out.print(c);
break;
case '"':
if (isAttributeValue && quote.equals("\""))
out.print(""");
else
out.print(c);
break;
case '\n':
if (isAttributeValue)
out.print("
");
else
out.print(c);
break;
case '\r':
if (isAttributeValue)
out.print("
");
else
out.print(c);
break;
default:
out.print(c);
}
}
}
protected class NamespaceContext {
private final Map namespaceMap;
public NamespaceContext() {
namespaceMap = new HashMap();
}
public NamespaceContext(NamespaceContext context) {
this();
namespaceMap.putAll(context.namespaceMap);
}
public boolean isPrefixRegistered(String prefix, String uri) {
return namespaceMap.containsKey(prefix) && namespaceMap.get(prefix).equals(uri);
}
public void registerNamespacePrefix(String prefix, String uri) {
if (!isPrefixRegistered(prefix, uri)) {
namespaceMap.put(prefix, uri);
}
}
public String getNamespace(String prefix) {
Object uri = namespaceMap.get(prefix);
return (uri == null) ? null : uri.toString();
}
}
}