package com.fasterxml.jackson.dataformat.xml.deser;
import java.io.IOException;
import javax.xml.stream.*;
import org.codehaus.stax2.XMLStreamLocation2;
import org.codehaus.stax2.XMLStreamReader2;
import org.codehaus.stax2.ri.Stax2ReaderAdapter;
import com.fasterxml.jackson.core.JsonLocation;
import com.fasterxml.jackson.dataformat.xml.util.StaxUtil;
/**
* Simple helper class used on top of STAX {@link XMLStreamReader} to further
* abstract out all irrelevant details, and to expose equivalent of flat token
* stream with no "fluff" tokens (comments, processing instructions, mixed
* content) all of which is just to simplify
* actual higher-level conversion to JSON tokens
*/
public class XmlTokenStream
{
// // // main token states:
public final static int XML_START_ELEMENT = 1;
public final static int XML_END_ELEMENT = 2;
public final static int XML_ATTRIBUTE_NAME = 3;
public final static int XML_ATTRIBUTE_VALUE = 4;
public final static int XML_TEXT = 5;
public final static int XML_END = 6;
// // // token replay states
private final static int REPLAY_START_DUP = 1;
private final static int REPLAY_END = 2;
private final static int REPLAY_START_DELAYED = 3;
/*
/**********************************************************************
/* Configuration
/**********************************************************************
*/
final protected XMLStreamReader2 _xmlReader;
final protected Object _sourceReference;
/*
/**********************************************************************
/* Parsing state
/**********************************************************************
*/
protected int _currentState;
protected int _attributeCount;
/**
* Index of the next attribute of the current START_ELEMENT
* to return (as field name and value pair), if any; -1
* when no attributes to return
*/
protected int _nextAttributeIndex = 0;
protected String _localName;
protected String _namespaceURI;
protected String _textValue;
/*
/**********************************************************************
/* State for handling virtual wrapping
/**********************************************************************
*/
/**
* Flag used to indicate that given element should be "replayed".
*/
protected int _repeatElement;
/**
* Wrapping state, if any active (null if none)
*/
protected ElementWrapper _currentWrapper;
/**
* In cases where we need to 'inject' a virtual END_ELEMENT, we may also
* need to restore START_ELEMENT afterwards; if so, this is where names
* are held.
*/
protected String _nextLocalName;
protected String _nextNamespaceURI;
/*
/**********************************************************************
/* Life-cycle
/**********************************************************************
*/
public XmlTokenStream(XMLStreamReader xmlReader, Object sourceRef)
{
_sourceReference = sourceRef;
// Let's ensure we point to START_ELEMENT...
if (xmlReader.getEventType() != XMLStreamConstants.START_ELEMENT) {
throw new IllegalArgumentException("Invalid XMLStreamReader passed: should be pointing to START_ELEMENT ("
+XMLStreamConstants.START_ELEMENT+"), instead got "+xmlReader.getEventType());
}
_xmlReader = Stax2ReaderAdapter.wrapIfNecessary(xmlReader);
_currentState = XML_START_ELEMENT;
_localName = _xmlReader.getLocalName();
_namespaceURI = _xmlReader.getNamespaceURI();
_attributeCount = _xmlReader.getAttributeCount();
}
public XMLStreamReader2 getXmlReader() {
return _xmlReader;
}
/*
/**********************************************************************
/* Public API
/**********************************************************************
*/
// DEBUGGING
/*
public int next() throws IOException
{
int n = next0();
switch (n) {
case XML_START_ELEMENT:
System.out.println(" XML-token: XML_START_ELEMENT '"+_localName+"'");
break;
case XML_END_ELEMENT:
System.out.println(" XML-token: XML_END_ELEMENT '"+_localName+"'");
break;
case XML_ATTRIBUTE_NAME:
System.out.println(" XML-token: XML_ATTRIBUTE_NAME '"+_localName+"'");
break;
case XML_ATTRIBUTE_VALUE:
System.out.println(" XML-token: XML_ATTRIBUTE_VALUE '"+_textValue+"'");
break;
case XML_TEXT:
System.out.println(" XML-token: XML_TEXT '"+_textValue+"'");
break;
case XML_END:
System.out.println(" XML-token: XML_END");
break;
default:
throw new IllegalStateException();
}
return n;
}
*/
public int next() throws IOException
{
if (_repeatElement != 0) {
return (_currentState = _handleRepeatElement());
}
try {
return _next();
} catch (XMLStreamException e) {
StaxUtil.throwXmlAsIOException(e);
return -1;
}
}
public void skipEndElement() throws IOException
{
int type = next();
if (type != XML_END_ELEMENT) {
throw new IOException("Expected END_ELEMENT, got event of type "+type);
}
}
public int getCurrentToken() { return _currentState; }
public String getText() { return _textValue; }
public String getLocalName() { return _localName; }
public String getNamespaceURI() { return _namespaceURI; }
public boolean hasAttributes() {
return (_currentState == XML_START_ELEMENT) && (_attributeCount > 0);
}
public void closeCompletely() throws IOException
{
try {
_xmlReader.closeCompletely();
} catch (XMLStreamException e) {
StaxUtil.throwXmlAsIOException(e);
}
}
public void close() throws IOException
{
try {
_xmlReader.close();
} catch (XMLStreamException e) {
StaxUtil.throwXmlAsIOException(e);
}
}
public JsonLocation getCurrentLocation() {
return _extractLocation(_xmlReader.getLocationInfo().getCurrentLocation());
}
public JsonLocation getTokenLocation() {
return _extractLocation(_xmlReader.getLocationInfo().getStartLocation());
}
/*
/**********************************************************************
/* Internal API: more esoteric methods
/**********************************************************************
*/
/**
* Method used to add virtual wrapping, which just duplicates START_ELEMENT
* stream points to, and its matching closing element.
*
* @since 2.1
*/
protected void repeatStartElement()
{
//System.out.println(" -> repeatStartElement for "+_localName);
// sanity check: can only be used when just returned START_ELEMENT:
if (_currentState != XML_START_ELEMENT) {
throw new IllegalStateException("Current state not XML_START_ELEMENT ("
+XML_START_ELEMENT+") but "+_currentState);
}
// Important: add wrapper, to keep track...
if (_currentWrapper == null) {
_currentWrapper = ElementWrapper.matchingWrapper(_currentWrapper, _localName, _namespaceURI);
} else {
_currentWrapper = ElementWrapper.matchingWrapper(_currentWrapper.getParent(), _localName, _namespaceURI);
}
_repeatElement = REPLAY_START_DUP;
}
/**
* Method called to skip any attributes current START_ELEMENT may have,
* so that they are not returned as token.
*
* @since 2.1
*/
protected void skipAttributes()
{
if (_currentState == XML_ATTRIBUTE_NAME) {
_attributeCount = 0;
_currentState = XML_START_ELEMENT;
} else if (_currentState == XML_START_ELEMENT) {
/* 06-Jan-2012, tatu: As per [#47] it looks like we should NOT do anything
* in this particular case, because it occurs when original element had
* no attributes and we now point to the first child element.
*/
// _attributeCount = 0;
} else if (_currentState == XML_TEXT) {
; // nothing to do... is it even legal?
} else {
throw new IllegalStateException("Current state not XML_START_ELEMENT or XML_ATTRIBUTE_NAME ("
+XML_START_ELEMENT+") but "+_currentState);
}
}
protected String convertToString() throws IOException
{
// only applicable to cases where START_OBJECT was induced by attributes
if (_currentState != XML_ATTRIBUTE_NAME || _nextAttributeIndex != 0) {
return null;
}
try {
String text = _collectUntilTag();
if (text != null && _xmlReader.getEventType() == XMLStreamReader.END_ELEMENT) {
if (_currentWrapper != null) {
_currentWrapper = _currentWrapper.getParent();
}
// just for diagnostics, reset to element name (from first attribute name)
_localName = _xmlReader.getLocalName();
_namespaceURI = _xmlReader.getNamespaceURI();
_attributeCount = 0;
_currentState = XML_TEXT;
_textValue = text;
return text;
}
} catch (XMLStreamException e) {
StaxUtil.throwXmlAsIOException(e);
}
// Anything to do in failed case? Roll back whatever we found or.. ?
return null;
}
/*
/**********************************************************************
/* Internal methods, parsing
/**********************************************************************
*/
private final int _next() throws XMLStreamException
{
switch (_currentState) {
case XML_ATTRIBUTE_VALUE:
++_nextAttributeIndex;
// fall through
case XML_START_ELEMENT: // attributes to return?
if (_nextAttributeIndex < _attributeCount) {
_localName = _xmlReader.getAttributeLocalName(_nextAttributeIndex);
_namespaceURI = _xmlReader.getAttributeNamespace(_nextAttributeIndex);
_textValue = _xmlReader.getAttributeValue(_nextAttributeIndex);
return (_currentState = XML_ATTRIBUTE_NAME);
}
// otherwise need to find START/END_ELEMENT or text
String text = _collectUntilTag();
// If it's START_ELEMENT, ignore any text
if (_xmlReader.getEventType() == XMLStreamReader.START_ELEMENT) {
return _initStartElement();
}
// For END_ELEMENT we will return text, if any
if (text != null) {
_textValue = text;
return (_currentState = XML_TEXT);
}
return _handleEndElement();
case XML_ATTRIBUTE_NAME:
// if we just returned name, will need to just send value next
return (_currentState = XML_ATTRIBUTE_VALUE);
case XML_TEXT:
// text is always followed by END_ELEMENT
return _handleEndElement();
case XML_END:
return XML_END;
// throw new IllegalStateException("No more XML tokens available (end of input)");
}
// Ok: must be END_ELEMENT; see what tag we get (or end)
switch (_skipUntilTag()) {
case XMLStreamConstants.END_DOCUMENT:
return (_currentState = XML_END);
case XMLStreamConstants.END_ELEMENT:
return _handleEndElement();
}
// START_ELEMENT...
return _initStartElement();
}
private final String _collectUntilTag() throws XMLStreamException
{
String text = null;
while (true) {
switch (_xmlReader.next()) {
case XMLStreamConstants.START_ELEMENT:
case XMLStreamConstants.END_ELEMENT:
case XMLStreamConstants.END_DOCUMENT:
return text;
// note: SPACE is ignorable (and seldom seen), not to be included
case XMLStreamConstants.CHARACTERS:
case XMLStreamConstants.CDATA:
if (text == null) {
text = _xmlReader.getText();
} else { // can be optimized in future, if need be:
text += _xmlReader.getText();
}
break;
default:
// any other type (proc instr, comment etc) is just ignored
}
}
}
private final int _skipUntilTag() throws XMLStreamException
{
while (_xmlReader.hasNext()) {
int type;
switch (type = _xmlReader.next()) {
case XMLStreamConstants.START_ELEMENT:
case XMLStreamConstants.END_ELEMENT:
case XMLStreamConstants.END_DOCUMENT:
return type;
default:
// any other type (proc instr, comment etc) is just ignored
}
}
throw new IllegalStateException("Expected to find a tag, instead reached end of input");
}
/*
/**********************************************************************
/* Internal methods, other
/**********************************************************************
*/
private final int _initStartElement() throws XMLStreamException
{
final String ns = _xmlReader.getNamespaceURI();
final String localName = _xmlReader.getLocalName();
_attributeCount = _xmlReader.getAttributeCount();
_nextAttributeIndex = 0;
/* Support for virtual wrapping: in wrapping, may either
* create a new wrapper scope (if in sub-tree, or matches
* wrapper element itself), or implicitly close existing
* scope.
*/
if (_currentWrapper != null) {
if (_currentWrapper.matchesWrapper(localName, ns)) {
_currentWrapper = _currentWrapper.intermediateWrapper();
} else {
// implicit end is more interesting:
_localName = _currentWrapper.getWrapperLocalName();
_namespaceURI = _currentWrapper.getWrapperNamespace();
_currentWrapper = _currentWrapper.getParent();
//System.out.println(" START_ELEMENT ("+localName+") not matching '"+_localName+"'; add extra XML-END-ELEMENT!");
// Important! We also need to restore the START_ELEMENT, so:
_nextLocalName = localName;
_nextNamespaceURI = ns;
_repeatElement = REPLAY_START_DELAYED;
return (_currentState = XML_END_ELEMENT);
}
}
_localName = localName;
_namespaceURI = ns;
return (_currentState = XML_START_ELEMENT);
}
/**
* Method called to handle details of repeating "virtual"
* start/end elements, needed for handling 'unwrapped' lists.
*/
protected int _handleRepeatElement() throws IOException
{
int type = _repeatElement;
_repeatElement = 0;
if (type == REPLAY_START_DUP) {
//System.out.println("handleRepeat for START_ELEMENT: "+_localName+" ("+_xmlReader.getLocalName()+")");
// important: add the virtual element second time, but not with name to match
_currentWrapper = _currentWrapper.intermediateWrapper();
return XML_START_ELEMENT;
}
if (type == REPLAY_END) {
//System.out.println("handleRepeat for END_ELEMENT: "+_localName+" ("+_xmlReader.getLocalName()+")");
_localName = _xmlReader.getLocalName();
_namespaceURI = _xmlReader.getNamespaceURI();
if (_currentWrapper != null) {
_currentWrapper = _currentWrapper.getParent();
}
return XML_END_ELEMENT;
}
if (type == REPLAY_START_DELAYED) {
if (_currentWrapper != null) {
_currentWrapper = _currentWrapper.intermediateWrapper();
}
_localName = _nextLocalName;
_namespaceURI = _nextNamespaceURI;
_nextLocalName = null;
_nextNamespaceURI = null;
//System.out.println("handleRepeat for START_DELAYED: "+_localName+" ("+_xmlReader.getLocalName()+")");
return XML_START_ELEMENT;
}
throw new IllegalStateException("Unrecognized type to repeat: "+type);
}
private final int _handleEndElement()
{
if (_currentWrapper != null) {
ElementWrapper w = _currentWrapper;
// important: if we close the scope, must duplicate END_ELEMENT as well
if (w.isMatching()) {
_repeatElement = REPLAY_END;
_localName = w.getWrapperLocalName();
_namespaceURI = w.getWrapperNamespace();
_currentWrapper = _currentWrapper.getParent();
//System.out.println(" IMPLICIT requestRepeat of END_ELEMENT '"+_localName);
} else {
_currentWrapper = _currentWrapper.getParent();
}
}
return (_currentState = XML_END_ELEMENT);
}
private JsonLocation _extractLocation(XMLStreamLocation2 location)
{
if (location == null) { // just for impls that might pass null...
return new JsonLocation(_sourceReference, -1, -1, -1);
}
return new JsonLocation(_sourceReference,
location.getCharacterOffset(),
location.getLineNumber(),
location.getColumnNumber());
}
// for DEBUGGING
@Override
public String toString()
{
StringBuilder sb = new StringBuilder();
sb.append("(Token stream:");
sb.append(" state=").append(_currentState);
sb.append(" attr#=").append(_attributeCount);
sb.append(" nextAttr#=").append(_nextAttributeIndex);
sb.append(" name=").append(_localName);
sb.append(" text=").append(_textValue);
sb.append(" repeat?=").append(_repeatElement);
sb.append(" wrapper=[").append(_currentWrapper);
sb.append("] repeatElement=").append(_repeatElement);
sb.append(" nextName=").append(_nextLocalName);
sb.append(")");
return sb.toString();
}
}