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Groovy: A powerful multi-faceted 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.xml
import groovy.xml.streamingmarkupsupport.AbstractStreamingBuilder
import groovy.xml.streamingmarkupsupport.BaseMarkupBuilder
import groovy.xml.streamingmarkupsupport.StreamingMarkupWriter
/**
* A builder class for creating XML markup. This implementation uses a
* {@link StreamingMarkupWriter} to handle output.
*
* Example:
*
System.out << new StreamingMarkupBuilder().bind {
* root {
* a( a1:'one' ) {
* b { mkp.yield( '3 < 5' ) }
* c( a2:'two', 'blah' )
* }
* }
* }
* Will output the following String, without newlines or indentation:
* <root>
* <a a1='one'>
* <b>3 < 5</b>
* <c a2='two'>blah</c>
* </a>
* </root>
* Notes:
*
* - that
mkp is a special namespace used to escape
* away from the normal building mode of the builder and get access
* to helper markup methods 'yield', 'pi', 'comment', 'out',
* 'namespaces', 'xmlDeclaration' and 'yieldUnescaped'.
*
* - Note that tab, newline and carriage return characters are escaped within attributes, i.e. will become ,
and
respectively
*
*/
@SuppressWarnings('Instanceof')
class StreamingMarkupBuilder extends AbstractStreamingBuilder {
boolean useDoubleQuotes = false
boolean expandEmptyElements = false
def getQt() { useDoubleQuotes ? '"' : "'" }
def pendingStack = []
/**
* Invoked by calling mkp.comment
*/
def commentClosure = {doc, pendingNamespaces, namespaces, namespaceSpecificTags, prefix, attrs, body, out ->
out.unescaped() << ''
}
/**
* Invoked by calling mkp.pi
*/
def piClosure = {doc, pendingNamespaces, namespaces, namespaceSpecificTags, prefix, attrs, body, out ->
attrs.each {target, instruction ->
out.unescaped() << '
def valueStr = value.toString()
valueStr.contains('\'') || (useDoubleQuotes && !valueStr.contains('"'))
}
} else {
out.unescaped() << "$target $instruction"
}
out.unescaped() << '?>'
}
}
/**
* Invoked by calling mkp.xmlDeclaration
*/
def declarationClosure = {doc, pendingNamespaces, namespaces, namespaceSpecificTags, prefix, attrs, body, out ->
out.unescaped() << '\n'
}
/**
* Invoked by calling mkp.yield. Used to render text to the
* output stream. Any XML reserved characters will be escaped to ensure
* well-formedness.
*/
def noopClosure = {doc, pendingNamespaces, namespaces, namespaceSpecificTags, prefix, attrs, body, out ->
body.each {
if (it instanceof Closure) {
def body1 = it.clone()
body1.delegate = doc
body1(doc)
} else if (it instanceof Buildable) {
it.build(doc)
} else {
out.escaped() << it
}
}
}
/**
* Invoked by calling mkp.yieldUnescaped. Used to render
* literal text or markup to the output stream. No escaping is done on the
* output.
*/
def unescapedClosure = {doc, pendingNamespaces, namespaces, namespaceSpecificTags, prefix, attrs, body, out ->
out.unescaped() << body
}
def tagClosure = {tag, doc, pendingNamespaces, namespaces, namespaceSpecificTags, prefix, attrs, body, out ->
boolean pendingIsDefaultNamespace = pendingNamespaces.containsKey(prefix) && !pendingNamespaces[prefix]
if (prefix != '') {
if (!(namespaces.containsKey(prefix) || pendingNamespaces.containsKey(prefix))) {
throw new GroovyRuntimeException("Namespace prefix: ${prefix} is not bound to a URI")
}
if (prefix != ':' && !pendingIsDefaultNamespace) tag = prefix + ':' + tag
}
out = out.unescaped() << "<${tag}"
attrs.each {key, value ->
if (key.contains('$')) {
def parts = key.tokenize('$')
String localpart = parts[1].contains('}') ? parts[1].tokenize('}')[1] : parts[1]
if (namespaces.containsKey(parts[0]) || pendingNamespaces.containsKey(parts[0])) {
key = parts[0] + ':' + localpart
} else {
throw new GroovyRuntimeException("bad attribute namespace tag: ${parts[0]} in ${key}")
}
}
out << " ${key}=" + qt
out.writingAttribute = true
"${value}".build(doc)
out.writingAttribute = false
out << qt
}
def hiddenNamespaces = [:]
pendingNamespaces.each { key, value ->
if (value) {
hiddenNamespaces[key] = namespaces[key]
namespaces[key] = value
out << ((key == ':') ? ' xmlns=' + qt : " xmlns:${key}=" + qt)
out.writingAttribute = true
"${value}".build(doc)
out.writingAttribute = false
out << qt
}
}
if (body == null && !expandEmptyElements) {
out << '/>'
} else {
out << '>'
pendingStack.push pendingNamespaces.clone()
pendingNamespaces.clear()
body.each {
if (it instanceof Closure) {
def body1 = it.clone()
body1.delegate = doc
body1(doc)
} else if (it instanceof Buildable) {
it.build(doc)
} else {
out.escaped() << it
}
}
pendingNamespaces.clear()
pendingNamespaces.putAll pendingStack.pop()
out << ""
}
hiddenNamespaces.each {key, value ->
if (value == null) {
namespaces.remove key
} else {
namespaces[key] = value
}
}
}
def builder = null
StreamingMarkupBuilder() {
specialTags.putAll([
'yield' : noopClosure,
'yieldUnescaped': unescapedClosure,
'xmlDeclaration': declarationClosure,
'comment' : commentClosure,
'pi' : piClosure
])
def nsSpecificTags = [
':' : [tagClosure, tagClosure, [:]], // the default namespace
'http://www.w3.org/XML/1998/namespace' : [tagClosure, tagClosure, [:]],
'http://www.codehaus.org/Groovy/markup/keywords': [badTagClosure, tagClosure, specialTags]
]
this.builder = new BaseMarkupBuilder(nsSpecificTags)
}
def encoding = null
/**
* Returns a {@link Writable} object, which may be used to render
* the markup directly to a String, or send the output to a stream.
*
* Examples:
*
* // get the markup as a string:
* new StreamingMarkupBuilder().bind { div { out << 'hello world' } }.toString()
*
* // send the output directly to a file:
* new StreamingMarkupBuilder().bind {
* div { out << 'hello world' }
* }.writeTo( new File('myFile.xml').newWriter() )
*
*
* @return a {@link Writable} to render the markup
*/
def bind(closure) {
def boundClosure = this.builder.bind(closure)
def enc = encoding // take a snapshot of the encoding when the closure is bound to the builder
def writable = { out ->
out = new StreamingMarkupWriter(out, enc, useDoubleQuotes)
boundClosure.trigger = out
out.flush()
}.asWritable()
writable
}
/**
* Convenience method for binding a single node.
* The call bindNode(node) is equivalent to bind{ out << node }.
* Returns a {@link Writable} object, which may be used to render
* the markup directly to a String, or send the output to a stream.
*
* @see #bind(Closure)
* @return a {@link Writable} to render the markup
*/
def bindNode(node) {
bind { out << node }
}
}
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