/*
* 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 org.apache.tuscany.sca.databinding.xml;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import javax.xml.namespace.NamespaceContext;
import javax.xml.namespace.QName;
import javax.xml.stream.Location;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
/**
* This is the new implementation of the XMLFramentStreamReader. The approach
* here is simple When the pull parser needs to generate events for a particular
* name-value(s) pair it always hands over (delegates) the task to another pull
* parser which knows how to deal with it The common types of name value pairs
* we'll come across are
*
* - String name/QName name - String value
*
- String name/QName name - String[] value
*
- QName name/String name - XMLStreamReader value
*
- QName name/String name - XMLStreamable value
*
- QName name/String name - Java bean
*
- QName name/String name - Datahandler
*
*
* As for the attributes, these are the possible combinations in the array
*
* - String name/QName name - String value
*
* Note that certain array methods have been deliberately removed to avoid
* complications. The generated code will take the trouble to lay the elements
* of the array in the correct order Hence there will be a parser impl
* that knows how to handle these types, and this parent parser will always
* delegate these tasks to the child pullparasers in effect this is one huge
* state machine that has only a few states and delegates things down to the
* child parsers whenever possible
*
* @version $Rev$ $Date$
*/
public class XMLFragmentStreamReaderImpl implements XMLFragmentStreamReader {
private static final int DELEGATED_STATE = 2;
private static final int END_ELEMENT_STATE = 1;
// states for this pullparser - it can only have four states
private static final int START_ELEMENT_STATE = 0;
private static final int TEXT_STATE = 3;
protected NamedProperty[] attributes;
// reference to the child reader
protected XMLFragmentStreamReader childReader;
// current property index
// initialized at zero
protected int index;
protected Map declaredNamespaceMap = new HashMap();
protected QName elementQName;
// we always create a new namespace context
protected DelegatingNamespaceContext namespaceContext = new DelegatingNamespaceContext();
protected NamedProperty[] elements;
// integer field that keeps the state of this
// parser.
protected int state = START_ELEMENT_STATE;
/*
* we need to pass in a namespace context since when delegated, we've no
* idea of the current namespace context. So it needs to be passed on here!
*/
public XMLFragmentStreamReaderImpl(QName elementQName, NamedProperty[] elements, NamedProperty[] attributes) {
// validate the lengths, since both the arrays are supposed
// to have
this.elements = elements == null ? new NamedProperty[0] : elements;
this.elementQName = elementQName;
this.attributes = attributes == null ? new NamedProperty[0] : attributes;
}
protected XMLFragmentStreamReaderImpl(QName elementQName) {
this.elementQName = elementQName;
}
/**
* add the namespace context
*/
public void setParentNamespaceContext(NamespaceContext nsContext) {
// register the namespace context passed in to this
this.namespaceContext.setParentNsContext(nsContext);
}
protected NamedProperty[] getElements() {
return elements;
}
protected NamedProperty[] getAttributes() {
return attributes;
}
protected QName[] getNamespaces() {
return new QName[0];
}
/**
* @param prefix
* @param uri
*/
protected void addToNsMap(String prefix, String uri) {
if (!uri.equals(namespaceContext.getNamespaceURI(prefix))) {
namespaceContext.pushNamespace(prefix, uri);
declaredNamespaceMap.put(prefix, uri);
}
}
public void close() throws XMLStreamException {
// do nothing here - we have no resources to free
}
public int getAttributeCount() {
return (state == DELEGATED_STATE) ? childReader.getAttributeCount() : (state == START_ELEMENT_STATE
? getAttributes().length : 0);
}
public String getAttributeLocalName(int i) {
if (state == DELEGATED_STATE) {
return childReader.getAttributeLocalName(i);
} else if (state == START_ELEMENT_STATE) {
QName name = getAttributeName(i);
if (name == null) {
return null;
} else {
return name.getLocalPart();
}
} else {
throw new IllegalStateException();
}
}
/**
* @param i
*/
public QName getAttributeName(int i) {
if (state == DELEGATED_STATE) {
return childReader.getAttributeName(i);
} else if (state == START_ELEMENT_STATE) {
if ((i >= (getAttributes().length)) || i < 0) { // out of range
return null;
} else {
// get the attribute pointer
QName attribPointer = getAttributes()[i].getKey();
// case one - attrib name is null
// this should be the pointer to the OMAttribute then
if (attribPointer == null) {
throw new UnsupportedOperationException();
} else if (attribPointer instanceof QName) {
return attribPointer;
} else {
return null;
}
}
} else {
throw new IllegalStateException(); // as per the API contract
}
}
public String getAttributeNamespace(int i) {
if (state == DELEGATED_STATE) {
return childReader.getAttributeNamespace(i);
} else if (state == START_ELEMENT_STATE) {
QName name = getAttributeName(i);
if (name == null) {
return null;
} else {
return name.getNamespaceURI();
}
} else {
throw new IllegalStateException();
}
}
public String getAttributePrefix(int i) {
if (state == DELEGATED_STATE) {
return childReader.getAttributePrefix(i);
} else if (state == START_ELEMENT_STATE) {
QName name = getAttributeName(i);
if (name == null) {
return null;
} else {
return name.getPrefix();
}
} else {
throw new IllegalStateException();
}
}
public String getAttributeType(int i) {
return null; // not supported
}
public String getAttributeValue(int i) {
if (state == DELEGATED_STATE) {
return childReader.getAttributeValue(i);
} else if (state == START_ELEMENT_STATE) {
if ((i >= (getAttributes().length)) || i < 0) { // out of range
return null;
} else {
// get the attribute pointer
QName attribPointer = getAttributes()[i].getKey();
Object omAttribObj = getAttributes()[i].getValue();
// case one - attrib name is null
// this should be the pointer to the OMAttribute then
if (attribPointer == null) {
throw new UnsupportedOperationException();
} else if (attribPointer instanceof QName) {
return (String)omAttribObj;
} else {
return null;
}
}
} else {
throw new IllegalStateException();
}
}
public String getAttributeValue(String nsUri, String localName) {
int attribCount = getAttributeCount();
String returnValue = null;
QName attribQualifiedName;
for (int i = 0; i < attribCount; i++) {
attribQualifiedName = getAttributeName(i);
if (nsUri == null) {
if (localName.equals(attribQualifiedName.getLocalPart())) {
returnValue = getAttributeValue(i);
break;
}
} else {
if (localName.equals(attribQualifiedName.getLocalPart()) && nsUri.equals(attribQualifiedName
.getNamespaceURI())) {
returnValue = getAttributeValue(i);
break;
}
}
}
return returnValue;
}
public String getCharacterEncodingScheme() {
return null; // TODO - should we return something for this ?
}
/**
* TODO implement the right contract for this
*
* @throws XMLStreamException
*/
public String getElementText() throws XMLStreamException {
if (state == DELEGATED_STATE) {
return childReader.getElementText();
} else {
return null;
}
}
// /////////////////////////////////////////////////////////////////////////
// / attribute handling
// /////////////////////////////////////////////////////////////////////////
public String getEncoding() {
if (state == DELEGATED_STATE) {
return childReader.getEncoding();
} else {
// we've no idea what the encoding is going to be in this case
// perhaps we ought to return some constant here, which the user
// might
// have access to change!
return null;
}
}
public int getEventType() {
if (state == START_ELEMENT_STATE) {
return START_ELEMENT;
} else if (state == END_ELEMENT_STATE) {
return END_ELEMENT;
} else if (state == TEXT_STATE) {
return CHARACTERS;
} else { // this is the delegated state
return childReader.getEventType();
}
}
public String getLocalName() {
if (state == DELEGATED_STATE) {
return childReader.getLocalName();
} else if (state != TEXT_STATE) {
return elementQName.getLocalPart();
} else {
throw new IllegalStateException();
}
}
/**
*/
public Location getLocation() {
// return a default location
return new Location() {
public int getCharacterOffset() {
return 0;
}
public int getColumnNumber() {
return 0;
}
public int getLineNumber() {
return 0;
}
public String getPublicId() {
return null;
}
public String getSystemId() {
return null;
}
};
}
public QName getName() {
if (state == DELEGATED_STATE) {
return childReader.getName();
} else if (state != TEXT_STATE) {
return elementQName;
} else {
throw new IllegalStateException();
}
}
public NamespaceContext getNamespaceContext() {
if (state == DELEGATED_STATE) {
return childReader.getNamespaceContext();
} else {
return namespaceContext;
}
}
public int getNamespaceCount() {
if (state == DELEGATED_STATE) {
return childReader.getNamespaceCount();
} else {
return declaredNamespaceMap.size();
}
}
/**
* @param i
*/
public String getNamespacePrefix(int i) {
if (state == DELEGATED_STATE) {
return childReader.getNamespacePrefix(i);
} else if (state != TEXT_STATE) {
// order the prefixes
String[] prefixes = makePrefixArray();
if ((i >= prefixes.length) || (i < 0)) {
return null;
} else {
return prefixes[i];
}
} else {
throw new IllegalStateException();
}
}
public String getNamespaceURI() {
if (state == DELEGATED_STATE) {
return childReader.getNamespaceURI();
} else if (state == TEXT_STATE) {
return null;
} else {
return elementQName.getNamespaceURI();
}
}
// /////////////////////////////////////////////////////////////////////////
// //////////// end of attribute handling
// /////////////////////////////////////////////////////////////////////////
// //////////////////////////////////////////////////////////////////////////
// //////////// namespace handling
// //////////////////////////////////////////////////////////////////////////
public String getNamespaceURI(int i) {
if (state == DELEGATED_STATE) {
return childReader.getNamespaceURI(i);
} else if (state != TEXT_STATE) {
String namespacePrefix = getNamespacePrefix(i);
return namespacePrefix == null ? null : (String)declaredNamespaceMap.get(namespacePrefix);
} else {
throw new IllegalStateException();
}
}
public String getNamespaceURI(String prefix) {
return namespaceContext.getNamespaceURI(prefix);
}
public String getPIData() {
throw new UnsupportedOperationException("Yet to be implemented !!");
}
public String getPITarget() {
throw new UnsupportedOperationException("Yet to be implemented !!");
}
public String getPrefix() {
if (state == DELEGATED_STATE) {
return childReader.getPrefix();
} else if (state == TEXT_STATE) {
return null;
} else {
String prefix = elementQName.getPrefix();
return "".equals(prefix) ? null : prefix;
}
}
// /////////////////////////////////////////////////////////////////////////
// /////// end of namespace handling
// /////////////////////////////////////////////////////////////////////////
/**
* @param key
* @throws IllegalArgumentException
*/
public Object getProperty(String key) throws IllegalArgumentException {
if (state == START_ELEMENT_STATE || state == END_ELEMENT_STATE) {
return null;
} else if (state == TEXT_STATE) {
return null;
} else if (state == DELEGATED_STATE) {
return childReader.getProperty(key);
} else {
return null;
}
}
public String getText() {
if (state == DELEGATED_STATE) {
return childReader.getText();
} else if (state == TEXT_STATE) {
return (String)getElements()[index - 1].getValue();
} else {
throw new IllegalStateException();
}
}
public char[] getTextCharacters() {
if (state == DELEGATED_STATE) {
return childReader.getTextCharacters();
} else if (state == TEXT_STATE) {
return getElements()[index - 1].getValue() == null ? new char[0] : ((String)getElements()[index - 1]
.getValue()).toCharArray();
} else {
throw new IllegalStateException();
}
}
private int copy(int sourceStart, char[] target, int targetStart, int length) {
char[] source = getTextCharacters();
if (sourceStart > source.length) {
throw new IndexOutOfBoundsException("source start > source length");
}
int sourceLen = source.length - sourceStart;
if (length > sourceLen) {
length = sourceLen;
}
System.arraycopy(source, sourceStart, target, targetStart, length);
return sourceLen;
}
public int getTextCharacters(int i, char[] chars, int i1, int i2) throws XMLStreamException {
if (state == DELEGATED_STATE) {
return childReader.getTextCharacters(i, chars, i1, i2);
} else if (state == TEXT_STATE) {
return copy(i, chars, i1, i2);
} else {
throw new IllegalStateException();
}
}
public int getTextLength() {
if (state == DELEGATED_STATE) {
return childReader.getTextLength();
} else if (state == TEXT_STATE) {
return getTextCharacters().length;
} else {
throw new IllegalStateException();
}
}
public int getTextStart() {
if (state == DELEGATED_STATE) {
return childReader.getTextStart();
} else if (state == TEXT_STATE) {
return 0; // assume text always starts at 0
} else {
throw new IllegalStateException();
}
}
public String getVersion() {
return null;
}
public boolean hasName() {
// since this parser always has a name, the hasName
// has to return true if we are still navigating this element
// if not we should ask the child reader for it.
if (state == DELEGATED_STATE) {
return childReader.hasName();
} else {
return state != TEXT_STATE;
}
}
/**
* @throws XMLStreamException
*/
public boolean hasNext() throws XMLStreamException {
if (state == DELEGATED_STATE) {
if (childReader.isDone()) {
// the child reader is done. We shouldn't be getting the
// hasNext result from the child pullparser then
return true;
} else {
return childReader.hasNext();
}
} else {
return state == START_ELEMENT_STATE || state == TEXT_STATE;
}
}
/**
* check the validity of this implementation
*/
public boolean hasText() {
if (state == DELEGATED_STATE) {
return childReader.hasText();
} else {
return state == TEXT_STATE;
}
}
/**
* we need to split out the calling to the populate namespaces separately
* since this needs to be done *after* setting the parent namespace context.
* We cannot assume it will happen at construction!
*/
public void init() {
// here we have an extra issue to attend to. we need to look at the
// prefixes and URIs (the combination) and populate a HashMap of
// namespaces. The HashMap of namespaces will be used to serve the
// namespace context
populateNamespaceContext();
}
public boolean isAttributeSpecified(int i) {
return false; // not supported
}
public boolean isCharacters() {
if (state == START_ELEMENT_STATE || state == END_ELEMENT_STATE) {
return false;
}
return childReader.isCharacters();
}
/**
* are we done ?
*/
public boolean isDone() {
return state == END_ELEMENT_STATE;
}
public boolean isEndElement() {
if (state == START_ELEMENT_STATE) {
return false;
} else if (state == END_ELEMENT_STATE) {
return true;
}
return childReader.isEndElement();
}
public boolean isStandalone() {
return true;
}
public boolean isStartElement() {
if (state == START_ELEMENT_STATE) {
return true;
} else if (state == END_ELEMENT_STATE) {
return false;
}
return childReader.isStartElement();
}
public boolean isWhiteSpace() {
if (state == START_ELEMENT_STATE || state == END_ELEMENT_STATE) {
return false;
}
return childReader.isWhiteSpace();
}
/**
* Get the prefix list from the HashTable and take that into an array
*/
private String[] makePrefixArray() {
String[] prefixes = declaredNamespaceMap.keySet().toArray(new String[declaredNamespaceMap.size()]);
Arrays.sort(prefixes);
return prefixes;
}
/**
* By far this should be the most important method in this class this method
* changes the state of the parser
*/
public int next() throws XMLStreamException {
int returnEvent = -1; // invalid state is the default state
switch (state) {
case START_ELEMENT_STATE:
// current element is start element. We should be looking at the
// property list and making a pullparser for the property value
if (getElements() == null || getElements().length == 0) {
// no properties - move to the end element state
// straight away
state = END_ELEMENT_STATE;
returnEvent = END_ELEMENT;
} else {
// there are properties. now we should delegate this task to
// a
// child reader depending on the property type
returnEvent = processProperties();
}
break;
case END_ELEMENT_STATE:
// we've reached the end element already. If the user tries to
// push
// further ahead then it is an exception
throw new XMLStreamException("Trying to go beyond the end of the pullparser");
case DELEGATED_STATE:
if (childReader.isDone()) {
// we've reached the end!
if (index > (getElements().length - 1)) {
state = END_ELEMENT_STATE;
returnEvent = END_ELEMENT;
} else {
returnEvent = processProperties();
}
} else {
returnEvent = childReader.next();
}
break;
case TEXT_STATE:
// if there are any more event we should be delegating to
// processProperties. if not we just return an end element
if (index > (getElements().length - 1)) {
state = END_ELEMENT_STATE;
returnEvent = END_ELEMENT;
} else {
returnEvent = processProperties();
}
break;
}
return returnEvent;
}
// /////////////////////////////////////////////////////////////////////////
// / Other utility methods
// ////////////////////////////////////////////////////////////////////////
/**
* TODO implement this
*
* @throws XMLStreamException
*/
public int nextTag() throws XMLStreamException {
return 0;
}
/**
* Populates a namespace context
*/
private void populateNamespaceContext() {
// first add the current element namespace to the namespace context
// declare it if not found
addToNsMap(elementQName.getPrefix(), elementQName.getNamespaceURI());
for (QName n : getNamespaces()) {
addToNsMap(n.getPrefix(), n.getNamespaceURI());
}
// traverse through the attributes and populate the namespace context
// the attrib list can be of many combinations
// the valid combinations are
// String - String
// QName - QName
// null - OMAttribute
for (int i = 0; i < getAttributes().length; i++) { // jump in two
QName attrQName = getAttributes()[i].getKey();
if (!"".equals(attrQName.getNamespaceURI())) {
addToNsMap(attrQName.getPrefix(), attrQName.getNamespaceURI());
}
}
}
/**
* A convenient method to reuse the properties
*
* @return event to be thrown
* @throws XMLStreamException
*/
private int processProperties() throws XMLStreamException {
// move to the next property depending on the current property
// index
QName propertyQName = getElements()[index].getKey();
boolean textFound = false;
if (propertyQName == null) {
throw new XMLStreamException("property key cannot be null!");
} else if (ELEMENT_TEXT.equals(propertyQName.getLocalPart())) {
// propPointer being a String has a special case
// that is it can be a the special constant ELEMENT_TEXT that
// says this text event
textFound = true;
}
// OK! we got the key. Now look at the value
Object propertyValue = getElements()[index].getValue();
// cater for the special case now
if (textFound) {
// no delegation here - make the parser null and immediately
// return with the event characters
childReader = null;
state = TEXT_STATE;
++index;
return CHARACTERS;
} else if (propertyValue == null) {
// if the value is null we delegate the work to a nullable
// parser
childReader = new NilElementStreamReader(propertyQName);
childReader.setParentNamespaceContext(this.namespaceContext);
childReader.init();
} else if (propertyValue instanceof String) {
// strings are handled by the NameValuePairStreamReader
childReader = new NameValuePairStreamReader(propertyQName, (String)propertyValue);
childReader.setParentNamespaceContext(this.namespaceContext);
childReader.init();
} else if (propertyValue instanceof String[]) {
// string[] are handled by the NameValueArrayStreamReader
// if the array is empty - skip it
if (((String[])propertyValue).length == 0) {
// advance the index
++index;
return processProperties();
} else {
childReader = new NameValueArrayStreamReader(propertyQName, (String[])propertyValue);
childReader.setParentNamespaceContext(this.namespaceContext);
childReader.init();
}
} else if (propertyValue instanceof XMLStreamable) {
// ADBbean has it's own method to get a reader
XMLStreamReader reader = ((XMLStreamable)propertyValue).getXMLStreamReader(propertyQName);
// we know for sure that this is an ADB XMLStreamreader.
// However we need to make sure that it is compatible
if (reader instanceof XMLFragmentStreamReader) {
childReader = (XMLFragmentStreamReader)reader;
childReader.setParentNamespaceContext(this.namespaceContext);
childReader.init();
} else {
// wrap it to make compatible
childReader = new WrappingXMLStreamReader(reader);
}
} else if (propertyValue instanceof XMLStreamReader) {
XMLStreamReader reader = (XMLStreamReader)propertyValue;
if (reader instanceof XMLFragmentStreamReader) {
childReader = (XMLFragmentStreamReader)reader;
childReader.setParentNamespaceContext(this.namespaceContext);
childReader.init();
} else {
// wrap it to make compatible
childReader = new WrappingXMLStreamReader(reader);
}
} else {
// all special possibilities has been tried! Let's treat
// the thing as a bean and try generating events from it
childReader = new WrappingXMLStreamReader(new BeanXMLStreamReaderImpl(propertyQName, propertyValue));
// we cannot register the namespace context here
}
// set the state here
state = DELEGATED_STATE;
// we are done with the delegation
// increment the property index
++index;
return childReader.getEventType();
}
public void require(int i, String string, String string1) throws XMLStreamException {
throw new UnsupportedOperationException();
}
public boolean standaloneSet() {
return true;
}
}