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JAXB (JSR 222) Reference Implementation
/*
* Copyright (c) 1997, 2020 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0, which is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package org.glassfish.jaxb.runtime.v2.runtime.unmarshaller;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;
import javax.xml.namespace.QName;
import javax.xml.stream.Location;
import javax.xml.stream.XMLEventReader;
import javax.xml.stream.XMLStreamConstants;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.events.*;
import java.util.Iterator;
/**
* This is a simple utility class that adapts StAX events from an
* {@link XMLEventReader} to unmarshaller events on a
* {@link XmlVisitor}, bridging between the two
* parser technologies.
*
* @author [email protected]
* @version 1.0
*/
final class StAXEventConnector extends StAXConnector {
// StAX event source
private final XMLEventReader staxEventReader;
/** Current event. */
private XMLEvent event;
/**
* Shared and reused {@link Attributes}.
*/
private final AttributesImpl attrs = new AttributesImpl();
/**
* SAX may fire consective characters event, but we don't allow it.
* so use this buffer to perform buffering.
*/
private final StringBuilder buffer = new StringBuilder();
private boolean seenText;
/**
* Construct a new StAX to SAX adapter that will convert a StAX event
* stream into a SAX event stream.
*
* @param staxCore
* StAX event source
* @param visitor
* sink
*/
public StAXEventConnector(XMLEventReader staxCore, XmlVisitor visitor) {
super(visitor);
staxEventReader = staxCore;
}
public void bridge() throws XMLStreamException {
try {
// remembers the nest level of elements to know when we are done.
int depth=0;
event = staxEventReader.peek();
if( !event.isStartDocument() && !event.isStartElement() )
throw new IllegalStateException();
// if the parser is on START_DOCUMENT, skip ahead to the first element
do {
event = staxEventReader.nextEvent();
} while( !event.isStartElement() );
handleStartDocument(event.asStartElement().getNamespaceContext());
OUTER:
while(true) {
// These are all of the events listed in the javadoc for
// XMLEvent.
// The spec only really describes 11 of them.
switch (event.getEventType()) {
case XMLStreamConstants.START_ELEMENT :
handleStartElement(event.asStartElement());
depth++;
break;
case XMLStreamConstants.END_ELEMENT :
depth--;
handleEndElement(event.asEndElement());
if(depth==0) break OUTER;
break;
case XMLStreamConstants.CHARACTERS :
case XMLStreamConstants.CDATA :
case XMLStreamConstants.SPACE :
handleCharacters(event.asCharacters());
break;
}
event=staxEventReader.nextEvent();
}
handleEndDocument();
event = null; // avoid keeping a stale reference
} catch (SAXException e) {
throw new XMLStreamException(e);
}
}
protected Location getCurrentLocation() {
return event.getLocation();
}
protected String getCurrentQName() {
QName qName;
if(event.isEndElement())
qName = event.asEndElement().getName();
else
qName = event.asStartElement().getName();
return getQName(qName.getPrefix(), qName.getLocalPart());
}
private void handleCharacters(Characters event) throws SAXException, XMLStreamException {
if(!predictor.expectText())
return; // text isn't expected. simply skip
seenText = true;
// check the next event
XMLEvent next;
while(true) {
next = staxEventReader.peek();
if(!isIgnorable(next))
break;
staxEventReader.nextEvent();
}
if(isTag(next)) {
// this is by far the common case --- you have abc or abc
visitor.text(event.getData());
return;
}
// otherwise we have things like "abcdef".
// concatenate all text
buffer.append(event.getData());
while(true) {
while(true) {
next = staxEventReader.peek();
if(!isIgnorable(next))
break;
staxEventReader.nextEvent();
}
if(isTag(next)) {
// found all adjacent text
visitor.text(buffer);
buffer.setLength(0);
return;
}
buffer.append(next.asCharacters().getData());
staxEventReader.nextEvent(); // consume
}
}
private boolean isTag(XMLEvent event) {
int eventType = event.getEventType();
return eventType==XMLEvent.START_ELEMENT || eventType==XMLEvent.END_ELEMENT;
}
private boolean isIgnorable(XMLEvent event) {
int eventType = event.getEventType();
return eventType==XMLEvent.COMMENT || eventType==XMLEvent.PROCESSING_INSTRUCTION;
}
private void handleEndElement(EndElement event) throws SAXException {
if(!seenText && predictor.expectText()) {
visitor.text("");
}
// fire endElement
QName qName = event.getName();
tagName.uri = fixNull(qName.getNamespaceURI());
tagName.local = qName.getLocalPart();
visitor.endElement(tagName);
// end namespace bindings
for( Iterator i = event.getNamespaces(); i.hasNext();) {
String prefix = fixNull(i.next().getPrefix()); // be defensive
visitor.endPrefixMapping(prefix);
}
seenText = false;
}
private void handleStartElement(StartElement event) throws SAXException {
// start namespace bindings
for (Iterator i = event.getNamespaces(); i.hasNext();) {
Namespace ns = (Namespace)i.next();
visitor.startPrefixMapping(
fixNull(ns.getPrefix()),
fixNull(ns.getNamespaceURI()));
}
// fire startElement
QName qName = event.getName();
tagName.uri = fixNull(qName.getNamespaceURI());
String localName = qName.getLocalPart();
tagName.uri = fixNull(qName.getNamespaceURI());
tagName.local = localName;
tagName.atts = getAttributes(event);
visitor.startElement(tagName);
seenText = false;
}
/**
* Get the attributes associated with the given START_ELEMENT StAXevent.
*
* @return the StAX attributes converted to an org.xml.sax.Attributes
*/
private Attributes getAttributes(StartElement event) {
attrs.clear();
// in SAX, namespace declarations are not part of attributes by default.
// (there's a property to control that, but as far as we are concerned
// we don't use it.) So don't add xmlns:* to attributes.
// gather non-namespace attrs
for (Iterator i = event.getAttributes(); i.hasNext();) {
Attribute staxAttr = (Attribute)i.next();
QName name = staxAttr.getName();
String uri = fixNull(name.getNamespaceURI());
String localName = name.getLocalPart();
String prefix = name.getPrefix();
String qName;
if (prefix == null || prefix.length() == 0)
qName = localName;
else
qName = prefix + ':' + localName;
String type = staxAttr.getDTDType();
String value = staxAttr.getValue();
attrs.addAttribute(uri, localName, qName, type, value);
}
return attrs;
}
}