org.jvnet.staxex.util.XMLStreamReaderToXMLStreamWriter Maven / Gradle / Ivy
Show all versions of stax-ex Show documentation
/*
* Copyright (c) 1997, 2018 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.jvnet.staxex.util;
import java.io.IOException;
import javax.xml.bind.attachment.AttachmentMarshaller;
import javax.xml.stream.XMLStreamConstants;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.XMLStreamWriter;
import javax.xml.XMLConstants;
import org.jvnet.staxex.Base64Data;
import org.jvnet.staxex.XMLStreamReaderEx;
import org.jvnet.staxex.XMLStreamWriterEx;
/**
* Reads a sub-tree from {@link XMLStreamReader} and writes to {@link XMLStreamWriter}
* as-is.
*
*
* This class can be sub-classed to implement a simple transformation logic.
*
* @author Kohsuke Kawaguchi
* @author Ryan Shoemaker
*/
public class XMLStreamReaderToXMLStreamWriter {
static public class Breakpoint {
protected XMLStreamReader reader;
protected XMLStreamWriter writer;
public Breakpoint(XMLStreamReader r, XMLStreamWriter w) { reader = r; writer = w; }
public XMLStreamReader reader() { return reader; }
public XMLStreamWriter writer() { return writer; }
public boolean proceedBeforeStartElement() { return true; }
public boolean proceedAfterStartElement() { return true; }
}
private static final int BUF_SIZE = 4096;
protected XMLStreamReader in;
protected XMLStreamWriter out;
private char[] buf;
boolean optimizeBase64Data = false;
AttachmentMarshaller mtomAttachmentMarshaller;
/**
* Reads one subtree and writes it out.
*
*
* The {@link XMLStreamWriter} never receives a start/end document event.
* Those need to be written separately by the caller.
*/
public void bridge(XMLStreamReader in, XMLStreamWriter out) throws XMLStreamException {
bridge(in, out, null);
}
public void bridge(Breakpoint breakPoint) throws XMLStreamException {
bridge(breakPoint.reader(), breakPoint.writer(), breakPoint);
}
private void bridge(XMLStreamReader in, XMLStreamWriter out, Breakpoint breakPoint) throws XMLStreamException {
assert in!=null && out!=null;
this.in = in;
this.out = out;
optimizeBase64Data = (in instanceof XMLStreamReaderEx);
if (out instanceof XMLStreamWriterEx && out instanceof MtomStreamWriter) {
mtomAttachmentMarshaller = ((MtomStreamWriter) out).getAttachmentMarshaller();
}
// remembers the nest level of elements to know when we are done.
int depth=0;
buf = new char[BUF_SIZE];
// if the parser is at the start tag, proceed to the first element
int event = getEventType();
if( event!=XMLStreamConstants.START_ELEMENT)
throw new IllegalStateException("The current event is not START_ELEMENT\n but " + event);
do {
// These are all of the events listed in the javadoc for
// XMLEvent.
// The spec only really describes 11 of them.
switch (event) {
case XMLStreamConstants.START_ELEMENT :
if (breakPoint != null && !breakPoint.proceedBeforeStartElement()) return;
depth++;
handleStartElement();
if (breakPoint != null && !breakPoint.proceedAfterStartElement()) return;
break;
case XMLStreamConstants.END_ELEMENT :
handleEndElement();
depth--;
if(depth==0)
return;
break;
case XMLStreamConstants.CHARACTERS :
handleCharacters();
break;
case XMLStreamConstants.ENTITY_REFERENCE :
handleEntityReference();
break;
case XMLStreamConstants.PROCESSING_INSTRUCTION :
handlePI();
break;
case XMLStreamConstants.COMMENT :
handleComment();
break;
case XMLStreamConstants.DTD :
handleDTD();
break;
case XMLStreamConstants.CDATA :
handleCDATA();
break;
case XMLStreamConstants.SPACE :
handleSpace();
break;
case XMLStreamConstants.END_DOCUMENT:
throw new XMLStreamException("Malformed XML at depth="+depth+", Reached EOF. Event="+event);
default :
throw new XMLStreamException("Cannot process event: " + event);
}
event=getNextEvent();
} while (depth!=0);
}
protected void handlePI() throws XMLStreamException {
out.writeProcessingInstruction(
in.getPITarget(),
in.getPIData());
}
protected void handleCharacters() throws XMLStreamException {
CharSequence c = null;
if (optimizeBase64Data) {
c = ((XMLStreamReaderEx)in).getPCDATA();
}
if ((c != null) && (c instanceof Base64Data)) {
if (mtomAttachmentMarshaller != null) {
Base64Data b64d = (Base64Data) c;
((XMLStreamWriterEx)out).writeBinary(b64d.getDataHandler());
} else {
try {
((Base64Data)c).writeTo(out);
} catch (IOException e) {
throw new XMLStreamException(e);
}
}
} else {
for (int start=0,read=buf.length; read == buf.length; start+=buf.length) {
read = in.getTextCharacters(start, buf, 0, buf.length);
out.writeCharacters(buf, 0, read);
}
}
}
protected void handleEndElement() throws XMLStreamException {
out.writeEndElement();
}
protected void handleStartElement() throws XMLStreamException {
String nsUri = in.getNamespaceURI();
if(nsUri==null)
out.writeStartElement(in.getLocalName());
else
out.writeStartElement(
fixNull(in.getPrefix()),
in.getLocalName(),
nsUri
);
// start namespace bindings
int nsCount = in.getNamespaceCount();
for (int i = 0; i < nsCount; i++) {
out.writeNamespace(
fixNull(in.getNamespacePrefix(i)), //StAX reader will return null for default NS
fixNull(in.getNamespaceURI(i))); // zephyr doesn't like null, I don't know what is correct, so just fix null to "" for now
}
// write attributes
int attCount = in.getAttributeCount();
for (int i = 0; i < attCount; i++) {
handleAttribute(i);
}
}
/**
* Writes out the {@code i}-th attribute of the current element.
*
*
* Used from {@link #handleStartElement()}.
*/
protected void handleAttribute(int i) throws XMLStreamException {
String nsUri = in.getAttributeNamespace(i);
String prefix = in.getAttributePrefix(i);
if (fixNull(nsUri).equals(XMLConstants.XMLNS_ATTRIBUTE_NS_URI)) {
//Its a namespace decl, ignore as it is already written.
return;
}
if(nsUri==null || prefix == null || prefix.equals("")) {
out.writeAttribute(
in.getAttributeLocalName(i),
in.getAttributeValue(i)
);
} else {
out.writeAttribute(
prefix,
nsUri,
in.getAttributeLocalName(i),
in.getAttributeValue(i)
);
}
}
protected void handleDTD() throws XMLStreamException {
out.writeDTD(in.getText());
}
protected void handleComment() throws XMLStreamException {
out.writeComment(in.getText());
}
protected void handleEntityReference() throws XMLStreamException {
out.writeEntityRef(in.getText());
}
protected void handleSpace() throws XMLStreamException {
handleCharacters();
}
protected void handleCDATA() throws XMLStreamException {
out.writeCData(in.getText());
}
private static String fixNull(String s) {
if(s==null) return "";
else return s;
}
private int getEventType() throws XMLStreamException {
int event = in.getEventType();
// if the parser is at the start tag, proceed to the first element
//Note - need to do this every time because we could be using a composite reader
if(event == XMLStreamConstants.START_DOCUMENT) {
// nextTag doesn't correctly handle DTDs
while( !in.isStartElement() ) {
event = in.next();
if (event == XMLStreamConstants.COMMENT)
handleComment();
}
}
return event;
}
private int getNextEvent() throws XMLStreamException {
in.next();
return getEventType();
}
}