cn.taketoday.util.xml.StaxEventXMLReader Maven / Gradle / Ivy
/*
* Original Author -> Harry Yang ([email protected]) https://taketoday.cn
* Copyright © TODAY & 2017 - 2022 All Rights Reserved.
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see [http://www.gnu.org/licenses/]
*/
package cn.taketoday.util.xml;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;
import java.util.Iterator;
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.Attribute;
import javax.xml.stream.events.Characters;
import javax.xml.stream.events.Comment;
import javax.xml.stream.events.DTD;
import javax.xml.stream.events.EndElement;
import javax.xml.stream.events.EntityDeclaration;
import javax.xml.stream.events.EntityReference;
import javax.xml.stream.events.Namespace;
import javax.xml.stream.events.NotationDeclaration;
import javax.xml.stream.events.ProcessingInstruction;
import javax.xml.stream.events.StartDocument;
import javax.xml.stream.events.StartElement;
import javax.xml.stream.events.XMLEvent;
import cn.taketoday.lang.Nullable;
import cn.taketoday.util.StringUtils;
/**
* SAX {@code XMLReader} that reads from a StAX {@code XMLEventReader}. Consumes {@code XMLEvents} from
* an {@code XMLEventReader}, and calls the corresponding methods on the SAX callback interfaces.
*
* @author Arjen Poutsma
* @see XMLEventReader
* @see #setContentHandler(ContentHandler)
* @see #setDTDHandler(org.xml.sax.DTDHandler)
* @see #setEntityResolver(org.xml.sax.EntityResolver)
* @see #setErrorHandler(org.xml.sax.ErrorHandler)
* @since 4.0
*/
@SuppressWarnings("rawtypes")
class StaxEventXMLReader extends AbstractStaxXMLReader {
private static final String DEFAULT_XML_VERSION = "1.0";
private final XMLEventReader reader;
private String xmlVersion = DEFAULT_XML_VERSION;
@Nullable
private String encoding;
/**
* Constructs a new instance of the {@code StaxEventXmlReader} that reads from
* the given {@code XMLEventReader}. The supplied event reader must be in
* {@code XMLStreamConstants.START_DOCUMENT} or {@code XMLStreamConstants.START_ELEMENT} state.
*
* @param reader the {@code XMLEventReader} to read from
* @throws IllegalStateException if the reader is not at the start of a document or element
*/
StaxEventXMLReader(XMLEventReader reader) {
try {
XMLEvent event = reader.peek();
if (event != null && !(event.isStartDocument() || event.isStartElement())) {
throw new IllegalStateException("XMLEventReader not at start of document or element");
}
}
catch (XMLStreamException ex) {
throw new IllegalStateException("Could not read first element: " + ex.getMessage());
}
this.reader = reader;
}
@Override
protected void parseInternal() throws SAXException, XMLStreamException {
boolean documentStarted = false;
boolean documentEnded = false;
int elementDepth = 0;
while (this.reader.hasNext() && elementDepth >= 0) {
XMLEvent event = this.reader.nextEvent();
if (!event.isStartDocument() && !event.isEndDocument() && !documentStarted) {
handleStartDocument(event);
documentStarted = true;
}
switch (event.getEventType()) {
case XMLStreamConstants.START_DOCUMENT -> {
handleStartDocument(event);
documentStarted = true;
}
case XMLStreamConstants.START_ELEMENT -> {
elementDepth++;
handleStartElement(event.asStartElement());
}
case XMLStreamConstants.END_ELEMENT -> {
elementDepth--;
if (elementDepth >= 0) {
handleEndElement(event.asEndElement());
}
}
case XMLStreamConstants.PROCESSING_INSTRUCTION -> handleProcessingInstruction((ProcessingInstruction) event);
case XMLStreamConstants.CHARACTERS,
XMLStreamConstants.SPACE,
XMLStreamConstants.CDATA -> handleCharacters(event.asCharacters());
case XMLStreamConstants.END_DOCUMENT -> {
handleEndDocument();
documentEnded = true;
}
case XMLStreamConstants.NOTATION_DECLARATION -> handleNotationDeclaration((NotationDeclaration) event);
case XMLStreamConstants.ENTITY_DECLARATION -> handleEntityDeclaration((EntityDeclaration) event);
case XMLStreamConstants.COMMENT -> handleComment((Comment) event);
case XMLStreamConstants.DTD -> handleDtd((DTD) event);
case XMLStreamConstants.ENTITY_REFERENCE -> handleEntityReference((EntityReference) event);
}
}
if (documentStarted && !documentEnded) {
handleEndDocument();
}
}
private void handleStartDocument(final XMLEvent event) throws SAXException {
if (event.isStartDocument()) {
StartDocument startDocument = (StartDocument) event;
String xmlVersion = startDocument.getVersion();
if (StringUtils.isNotEmpty(xmlVersion)) {
this.xmlVersion = xmlVersion;
}
if (startDocument.encodingSet()) {
this.encoding = startDocument.getCharacterEncodingScheme();
}
}
ContentHandler contentHandler = getContentHandler();
if (contentHandler != null) {
final Location location = event.getLocation();
StaxStreamXMLReader.setDocumentLocator(contentHandler, location, xmlVersion, encoding);
}
}
private void handleStartElement(StartElement startElement) throws SAXException {
if (getContentHandler() != null) {
QName qName = startElement.getName();
if (hasNamespacesFeature()) {
for (Iterator i = startElement.getNamespaces(); i.hasNext(); ) {
Namespace namespace = (Namespace) i.next();
startPrefixMapping(namespace.getPrefix(), namespace.getNamespaceURI());
}
for (Iterator i = startElement.getAttributes(); i.hasNext(); ) {
Attribute attribute = (Attribute) i.next();
QName attributeName = attribute.getName();
startPrefixMapping(attributeName.getPrefix(), attributeName.getNamespaceURI());
}
getContentHandler().startElement(qName.getNamespaceURI(), qName.getLocalPart(), toQualifiedName(qName),
getAttributes(startElement));
}
else {
getContentHandler().startElement("", "", toQualifiedName(qName), getAttributes(startElement));
}
}
}
private void handleCharacters(Characters characters) throws SAXException {
char[] data = characters.getData().toCharArray();
if (getContentHandler() != null && characters.isIgnorableWhiteSpace()) {
getContentHandler().ignorableWhitespace(data, 0, data.length);
return;
}
if (characters.isCData() && getLexicalHandler() != null) {
getLexicalHandler().startCDATA();
}
if (getContentHandler() != null) {
getContentHandler().characters(data, 0, data.length);
}
if (characters.isCData() && getLexicalHandler() != null) {
getLexicalHandler().endCDATA();
}
}
private void handleEndElement(EndElement endElement) throws SAXException {
if (getContentHandler() != null) {
QName qName = endElement.getName();
if (hasNamespacesFeature()) {
getContentHandler().endElement(qName.getNamespaceURI(), qName.getLocalPart(), toQualifiedName(qName));
for (Iterator i = endElement.getNamespaces(); i.hasNext(); ) {
Namespace namespace = (Namespace) i.next();
endPrefixMapping(namespace.getPrefix());
}
}
else {
getContentHandler().endElement("", "", toQualifiedName(qName));
}
}
}
private void handleEndDocument() throws SAXException {
if (getContentHandler() != null) {
getContentHandler().endDocument();
}
}
private void handleNotationDeclaration(NotationDeclaration declaration) throws SAXException {
if (getDTDHandler() != null) {
getDTDHandler().notationDecl(declaration.getName(), declaration.getPublicId(), declaration.getSystemId());
}
}
private void handleEntityDeclaration(EntityDeclaration entityDeclaration) throws SAXException {
if (getDTDHandler() != null) {
getDTDHandler().unparsedEntityDecl(entityDeclaration.getName(), entityDeclaration.getPublicId(),
entityDeclaration.getSystemId(), entityDeclaration.getNotationName());
}
}
private void handleProcessingInstruction(ProcessingInstruction pi) throws SAXException {
if (getContentHandler() != null) {
getContentHandler().processingInstruction(pi.getTarget(), pi.getData());
}
}
private void handleComment(Comment comment) throws SAXException {
if (getLexicalHandler() != null) {
char[] ch = comment.getText().toCharArray();
getLexicalHandler().comment(ch, 0, ch.length);
}
}
private void handleDtd(DTD dtd) throws SAXException {
if (getLexicalHandler() != null) {
Location location = dtd.getLocation();
getLexicalHandler().startDTD(null, location.getPublicId(), location.getSystemId());
}
if (getLexicalHandler() != null) {
getLexicalHandler().endDTD();
}
}
private void handleEntityReference(EntityReference reference) throws SAXException {
if (getLexicalHandler() != null) {
getLexicalHandler().startEntity(reference.getName());
}
if (getLexicalHandler() != null) {
getLexicalHandler().endEntity(reference.getName());
}
}
private Attributes getAttributes(StartElement event) {
AttributesImpl attributes = new AttributesImpl();
for (Iterator i = event.getAttributes(); i.hasNext(); ) {
Attribute attribute = (Attribute) i.next();
QName qName = attribute.getName();
String namespace = qName.getNamespaceURI();
if (namespace == null || !hasNamespacesFeature()) {
namespace = "";
}
String type = attribute.getDTDType();
if (type == null) {
type = "CDATA";
}
attributes.addAttribute(namespace, qName.getLocalPart(), toQualifiedName(qName), type, attribute.getValue());
}
if (hasNamespacePrefixesFeature()) {
for (Iterator i = event.getNamespaces(); i.hasNext(); ) {
Namespace namespace = (Namespace) i.next();
String prefix = namespace.getPrefix();
String namespaceUri = namespace.getNamespaceURI();
String qName;
if (StringUtils.isNotEmpty(prefix)) {
qName = "xmlns:" + prefix;
}
else {
qName = "xmlns";
}
attributes.addAttribute("", "", qName, "CDATA", namespaceUri);
}
}
return attributes;
}
}
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