org.apache.axiom.util.stax.xop.XOPEncodingStreamReader Maven / Gradle / Ivy
/*
* 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.axiom.util.stax.xop;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import javax.activation.DataHandler;
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;
import org.apache.axiom.ext.stax.datahandler.DataHandlerReader;
/**
* {@link XMLStreamReader} wrapper that encodes XOP. It assumes that the underlying reader
* implements the extension defined by {@link DataHandlerReader} so that it can identify the
* information items to optimize (by looking for
* {@link javax.xml.stream.XMLStreamConstants#CHARACTERS} events for which
* {@link DataHandlerReader#isBinary()} returns true). The {@link DataHandler}
* objects for the parts referenced by xop:Include element information items produced by
* an instance of this class can be retrieved using the {@link #getDataHandler(String)} method.
*
* Note that the primary purpose of this class is not to serialize an XML infoset to an XOP package
* (this is better done using {@link XOPEncodingStreamWriter}), but rather to optimize interaction
* (by exchanging {@link DataHandler} objects instead of base64 encoded representations) with
* databinding frameworks that understand XOP, but that are not aware of the
* {@link DataHandlerReader} extension.
*
* This class defers loading of {@link DataHandler} objects until {@link #getDataHandler(String)} is
* called, except if this is not supported by the underlying stream.
*/
public class XOPEncodingStreamReader extends XOPEncodingStreamWrapper implements XMLStreamReader {
/**
* Wrapper that adds the XOP namespace to another namespace context.
*/
private static class NamespaceContextWrapper implements NamespaceContext {
private static final List xopPrefixList = Arrays.asList(new String[] {
XOPConstants.DEFAULT_PREFIX });
private final NamespaceContext parent;
public NamespaceContextWrapper(NamespaceContext parent) {
this.parent = parent;
}
public String getNamespaceURI(String prefix) {
return XOPConstants.DEFAULT_PREFIX.equals(prefix)
? XOPConstants.NAMESPACE_URI
: parent.getNamespaceURI(prefix);
}
public String getPrefix(String namespaceURI) {
return XOPConstants.NAMESPACE_URI.equals(namespaceURI)
? XOPConstants.DEFAULT_PREFIX
: parent.getPrefix(namespaceURI);
}
public Iterator getPrefixes(String namespaceURI) {
Iterator prefixes = parent.getPrefixes(namespaceURI);
if (XOPConstants.NAMESPACE_URI.equals(namespaceURI)) {
if (!prefixes.hasNext()) {
return xopPrefixList.iterator();
} else {
// This case is very unusual
List prefixList = new ArrayList();
do {
prefixList.add(prefixes.next());
} while (prefixes.hasNext());
prefixList.add(XOPConstants.DEFAULT_PREFIX);
return prefixList.iterator();
}
} else {
return prefixes;
}
}
}
private static final int STATE_PASS_THROUGH = 0;
private static final int STATE_XOP_INCLUDE_START_ELEMENT = 1;
private static final int STATE_XOP_INCLUDE_END_ELEMENT = 2;
private final XMLStreamReader parent;
private final DataHandlerReader dataHandlerReader;
private int state = STATE_PASS_THROUGH;
private String currentContentID;
/**
* Constructor.
*
* @param parent
* The XML stream to encode. The reader must implement the extension defined by
* {@link DataHandlerReader}.
* @param contentIDGenerator
* used to generate content IDs for the binary content exposed as
* xop:Include element information items
* @param optimizationPolicy
* the policy to apply to decide which binary content to optimize
*
* @throws IllegalArgumentException
* if the provided {@link XMLStreamReader} doesn't implement the extension defined
* by {@link DataHandlerReader}
*/
public XOPEncodingStreamReader(XMLStreamReader parent, ContentIDGenerator contentIDGenerator,
OptimizationPolicy optimizationPolicy) {
super(contentIDGenerator, optimizationPolicy);
this.parent = parent;
DataHandlerReader dataHandlerReader;
try {
dataHandlerReader = (DataHandlerReader)parent.getProperty(DataHandlerReader.PROPERTY);
} catch (IllegalArgumentException ex) {
dataHandlerReader = null;
}
if (dataHandlerReader == null) {
throw new IllegalArgumentException("The supplied XMLStreamReader doesn't implement the DataHandlerReader extension");
}
this.dataHandlerReader = dataHandlerReader;
}
public int next() throws XMLStreamException {
switch (state) {
case STATE_XOP_INCLUDE_START_ELEMENT:
state = STATE_XOP_INCLUDE_END_ELEMENT;
return END_ELEMENT;
case STATE_XOP_INCLUDE_END_ELEMENT:
state = STATE_PASS_THROUGH;
currentContentID = null;
// Fall through
default:
int event = parent.next();
if (event == CHARACTERS && dataHandlerReader.isBinary()) {
String contentID;
try {
if (dataHandlerReader.isDeferred()) {
contentID = processDataHandler(
dataHandlerReader.getDataHandlerProvider(),
dataHandlerReader.getContentID(),
dataHandlerReader.isOptimized());
} else {
contentID = processDataHandler(
dataHandlerReader.getDataHandler(),
dataHandlerReader.getContentID(),
dataHandlerReader.isOptimized());
}
} catch (IOException ex) {
throw new XMLStreamException("Error while processing data handler", ex);
}
if (contentID != null) {
currentContentID = contentID;
state = STATE_XOP_INCLUDE_START_ELEMENT;
return START_ELEMENT;
} else {
return CHARACTERS;
}
} else {
return event;
}
}
}
public boolean hasNext() throws XMLStreamException {
return state == STATE_PASS_THROUGH ? parent.hasNext() : true;
}
public int nextTag() throws XMLStreamException {
switch (state) {
case STATE_XOP_INCLUDE_START_ELEMENT:
state = STATE_XOP_INCLUDE_END_ELEMENT;
return END_ELEMENT;
case STATE_XOP_INCLUDE_END_ELEMENT:
currentContentID = null;
// Fall through
default:
return parent.nextTag();
}
}
public void require(int type, String namespaceURI, String localName) throws XMLStreamException {
if (state == STATE_PASS_THROUGH) {
parent.require(type, namespaceURI, localName);
} else {
if (state == STATE_XOP_INCLUDE_START_ELEMENT && type != START_ELEMENT
|| state == STATE_XOP_INCLUDE_END_ELEMENT && type != END_ELEMENT
|| namespaceURI != null && !namespaceURI.equals(XOPConstants.NAMESPACE_URI)
|| localName != null && !localName.equals(XOPConstants.INCLUDE)) {
throw new XMLStreamException();
}
}
}
public Location getLocation() {
return parent.getLocation();
}
public void close() throws XMLStreamException {
parent.close();
}
public Object getProperty(String name) throws IllegalArgumentException {
return parent.getProperty(name);
}
public String getEncoding() {
return parent.getEncoding();
}
public String getCharacterEncodingScheme() {
return parent.getCharacterEncodingScheme();
}
public String getVersion() {
return parent.getVersion();
}
public boolean isStandalone() {
return parent.isStandalone();
}
public boolean standaloneSet() {
return parent.standaloneSet();
}
public String getPIData() {
return parent.getPIData();
}
public String getPITarget() {
return parent.getPITarget();
}
public int getAttributeCount() {
switch (state) {
case STATE_XOP_INCLUDE_START_ELEMENT:
return 1;
case STATE_XOP_INCLUDE_END_ELEMENT:
throw new IllegalStateException();
default:
return parent.getAttributeCount();
}
}
public String getAttributeLocalName(int index) {
switch (state) {
case STATE_XOP_INCLUDE_START_ELEMENT:
if (index != 0) {
throw new IllegalArgumentException();
}
return XOPConstants.HREF;
case STATE_XOP_INCLUDE_END_ELEMENT:
throw new IllegalStateException();
default:
return parent.getAttributeLocalName(index);
}
}
public QName getAttributeName(int index) {
switch (state) {
case STATE_XOP_INCLUDE_START_ELEMENT:
if (index != 0) {
throw new IllegalArgumentException();
}
return new QName(XOPConstants.HREF);
case STATE_XOP_INCLUDE_END_ELEMENT:
throw new IllegalStateException();
default:
return parent.getAttributeName(index);
}
}
public String getAttributeNamespace(int index) {
switch (state) {
case STATE_XOP_INCLUDE_START_ELEMENT:
if (index != 0) {
throw new IllegalArgumentException();
}
return null;
case STATE_XOP_INCLUDE_END_ELEMENT:
throw new IllegalStateException();
default:
return parent.getAttributeNamespace(index);
}
}
public String getAttributePrefix(int index) {
switch (state) {
case STATE_XOP_INCLUDE_START_ELEMENT:
if (index != 0) {
throw new IllegalArgumentException();
}
return null;
case STATE_XOP_INCLUDE_END_ELEMENT:
throw new IllegalStateException();
default:
return parent.getAttributePrefix(index);
}
}
public String getAttributeType(int index) {
switch (state) {
case STATE_XOP_INCLUDE_START_ELEMENT:
if (index != 0) {
throw new IllegalArgumentException();
}
return "CDATA";
case STATE_XOP_INCLUDE_END_ELEMENT:
throw new IllegalStateException();
default:
return parent.getAttributeType(index);
}
}
public String getAttributeValue(int index) {
switch (state) {
case STATE_XOP_INCLUDE_START_ELEMENT:
if (index != 0) {
throw new IllegalArgumentException();
}
// We don't use full URL encoding here, because this might cause
// interoperability issues. The specs (RFC 2111 and 2392) are not very clear
// on which characters should be URL encoded, but one can consider that '%'
// is the only really unsafe character.
return "cid:" + currentContentID.replaceAll("%", "%25");
case STATE_XOP_INCLUDE_END_ELEMENT:
throw new IllegalStateException();
default:
return parent.getAttributeValue(index);
}
}
public boolean isAttributeSpecified(int index) {
switch (state) {
case STATE_XOP_INCLUDE_START_ELEMENT:
if (index != 0) {
throw new IllegalArgumentException();
}
return true;
case STATE_XOP_INCLUDE_END_ELEMENT:
throw new IllegalStateException();
default:
return parent.isAttributeSpecified(index);
}
}
public String getAttributeValue(String namespaceURI, String localName) {
switch (state) {
case STATE_XOP_INCLUDE_START_ELEMENT:
if ((namespaceURI == null || namespaceURI.length() == 0)
&& localName.equals(XOPConstants.HREF)) {
return "cid:" + currentContentID;
} else {
return null;
}
case STATE_XOP_INCLUDE_END_ELEMENT:
throw new IllegalStateException();
default:
return parent.getAttributeValue(namespaceURI, localName);
}
}
public String getElementText() throws XMLStreamException {
switch (state) {
case STATE_XOP_INCLUDE_START_ELEMENT:
state = STATE_XOP_INCLUDE_END_ELEMENT;
return "";
case STATE_XOP_INCLUDE_END_ELEMENT:
throw new IllegalStateException();
default:
return parent.getElementText();
}
}
public int getEventType() {
switch (state) {
case STATE_XOP_INCLUDE_START_ELEMENT:
return START_ELEMENT;
case STATE_XOP_INCLUDE_END_ELEMENT:
return END_ELEMENT;
default:
return parent.getEventType();
}
}
public String getNamespaceURI() {
return state == STATE_PASS_THROUGH ? parent.getNamespaceURI() : XOPConstants.NAMESPACE_URI;
}
public String getLocalName() {
return state == STATE_PASS_THROUGH ? parent.getLocalName() : XOPConstants.INCLUDE;
}
public String getPrefix() {
return state == STATE_PASS_THROUGH ? parent.getPrefix() : XOPConstants.DEFAULT_PREFIX;
}
public QName getName() {
return state == STATE_PASS_THROUGH ? parent.getName() : XOPConstants.INCLUDE_QNAME;
}
public NamespaceContext getNamespaceContext() {
NamespaceContext ctx = parent.getNamespaceContext();
if (state != STATE_PASS_THROUGH) {
ctx = new NamespaceContextWrapper(ctx);
}
return ctx;
}
public String getNamespaceURI(String prefix) {
if (state != STATE_PASS_THROUGH && XOPConstants.DEFAULT_PREFIX.equals(prefix)) {
return XOPConstants.NAMESPACE_URI;
} else {
return parent.getNamespaceURI(prefix);
}
}
public int getNamespaceCount() {
return state == STATE_PASS_THROUGH ? parent.getNamespaceCount() : 1;
}
public String getNamespacePrefix(int index) {
if (state == STATE_PASS_THROUGH) {
return parent.getNamespacePrefix(index);
} else if (index != 0) {
throw new IllegalArgumentException();
} else {
return XOPConstants.DEFAULT_PREFIX;
}
}
public String getNamespaceURI(int index) {
if (state == STATE_PASS_THROUGH) {
return parent.getNamespaceURI(index);
} else if (index != 0) {
throw new IllegalArgumentException();
} else {
return XOPConstants.NAMESPACE_URI;
}
}
public String getText() {
if (state == STATE_PASS_THROUGH) {
return parent.getText();
} else {
throw new IllegalStateException();
}
}
public int getTextStart() {
if (state == STATE_PASS_THROUGH) {
return parent.getTextStart();
} else {
throw new IllegalStateException();
}
}
public int getTextLength() {
if (state == STATE_PASS_THROUGH) {
return parent.getTextLength();
} else {
throw new IllegalStateException();
}
}
public char[] getTextCharacters() {
if (state == STATE_PASS_THROUGH) {
return parent.getTextCharacters();
} else {
throw new IllegalStateException();
}
}
public int getTextCharacters(int sourceStart, char[] target, int targetStart, int length)
throws XMLStreamException {
if (state == STATE_PASS_THROUGH) {
return parent.getTextCharacters(sourceStart, target, targetStart, length);
} else {
throw new IllegalStateException();
}
}
public boolean hasName() {
return state == STATE_PASS_THROUGH ? parent.hasName() : true;
}
public boolean hasText() {
return state == STATE_PASS_THROUGH ? parent.hasText() : false;
}
public boolean isCharacters() {
return state == STATE_PASS_THROUGH ? parent.isCharacters() : false;
}
public boolean isWhiteSpace() {
return state == STATE_PASS_THROUGH ? parent.isWhiteSpace() : false;
}
public boolean isStartElement() {
switch (state) {
case STATE_XOP_INCLUDE_START_ELEMENT: return true;
case STATE_XOP_INCLUDE_END_ELEMENT: return false;
default: return parent.isStartElement();
}
}
public boolean isEndElement() {
switch (state) {
case STATE_XOP_INCLUDE_START_ELEMENT: return false;
case STATE_XOP_INCLUDE_END_ELEMENT: return true;
default: return parent.isEndElement();
}
}
}