org.apache.axiom.om.util.OMXMLStreamReaderValidator Maven / Gradle / Ivy
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* 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.om.util;
import org.apache.axiom.om.OMException;
import org.apache.axiom.om.OMXMLStreamReader;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import javax.activation.DataHandler;
import javax.xml.namespace.NamespaceContext;
import javax.xml.namespace.QName;
import javax.xml.stream.Location;
import javax.xml.stream.XMLStreamConstants;
import javax.xml.stream.XMLStreamException;
import java.util.Stack;
/**
* There are several places in the code where events are passed from
* a source to a consumer using XMLStreamReader events.
*
* OMXMLStreamReader (impl)--> consumer of XMLStreamReader events
*
* This simple class can be interjected as a filter and used to do some simple validation.
* Validating the events coming from source (impl) can help find and correct errors
* when they occur. Otherwise the errors may be caught much further downstream and hard to fix.
*
* OMXMLStreamReader (impl)--> OMXMLStreamReaderValiator-> consumer of XMLStreamReader events
*
*
* In the initial version, the XMStreamValidator ensures that the start element events match the
* end element events.
*
*/
public class OMXMLStreamReaderValidator implements OMXMLStreamReader {
private static Log log = LogFactory.getLog(OMXMLStreamReaderValidator.class);
private static boolean IS_DEBUG_ENABLED = log.isDebugEnabled();
private static boolean IS_ADV_DEBUG_ENABLED = false; // Turn this on to trace every event
private final OMXMLStreamReader delegate; // Actual XMLStreamReader implementation
private boolean throwExceptions = false; // Indicates whether OMException should be thrown if errors are disovered
private Stack stack = new Stack(); // Stack keeps track of the nested element QName
/**
* @param delegate XMLStreamReader to validate
* @param throwExceptions (true if exceptions should be thrown when errors are encountered)
*/
public OMXMLStreamReaderValidator(OMXMLStreamReader delegate, boolean throwExceptions) {
super();
this.delegate = delegate;
this.throwExceptions = throwExceptions;
}
public int next() throws XMLStreamException {
int event = delegate.next();
logParserState();
// Make sure that the start element and end element events match.
// Mismatched events are a key indication that the delegate stream reader is
// broken or corrupted.
switch (event) {
case XMLStreamConstants.START_ELEMENT:
stack.push(delegate.getName());
break;
case XMLStreamConstants.END_ELEMENT:
QName delegateQName = delegate.getName();
if (stack.isEmpty()) {
reportMismatchedEndElement(null, delegateQName);
} else {
QName expectedQName = (QName) stack.pop();
if (!expectedQName.equals(delegateQName)) {
reportMismatchedEndElement(expectedQName, delegateQName);
}
}
break;
default :
}
return event;
}
/**
* Report a mismatched end element.
* @param expectedQName
* @param delegateQName
*/
private void reportMismatchedEndElement(QName expectedQName, QName delegateQName) {
String text = null;
if (expectedQName == null) {
text = "An END_ELEMENT event for " + delegateQName +
" was encountered, but the START_ELEMENT stack is empty.";
} else {
text = "An END_ELEMENT event for " + delegateQName +
" was encountered. But this does match the corresponding START_ELEMENT " +
expectedQName + " event.";
}
if (IS_DEBUG_ENABLED) {
log.debug(text);
}
if (throwExceptions) {
throw new OMException(text);
}
}
public void close() throws XMLStreamException {
delegate.close();
}
public int getAttributeCount() {
return delegate.getAttributeCount();
}
public String getAttributeLocalName(int arg0) {
return delegate.getAttributeLocalName(arg0);
}
public QName getAttributeName(int arg0) {
return delegate.getAttributeName(arg0);
}
public String getAttributeNamespace(int arg0) {
return delegate.getAttributeNamespace(arg0);
}
public String getAttributePrefix(int arg0) {
return delegate.getAttributePrefix(arg0);
}
public String getAttributeType(int arg0) {
return delegate.getAttributeType(arg0);
}
public String getAttributeValue(int arg0) {
return delegate.getAttributeValue(arg0);
}
public String getAttributeValue(String arg0, String arg1) {
return delegate.getAttributeValue(arg0, arg1);
}
public String getCharacterEncodingScheme() {
return delegate.getCharacterEncodingScheme();
}
public String getElementText() throws XMLStreamException {
return delegate.getElementText();
}
public String getEncoding() {
return delegate.getEncoding();
}
public int getEventType() {
return delegate.getEventType();
}
public String getLocalName() {
return delegate.getLocalName();
}
public Location getLocation() {
return delegate.getLocation();
}
public QName getName() {
return delegate.getName();
}
public NamespaceContext getNamespaceContext() {
return delegate.getNamespaceContext();
}
public int getNamespaceCount() {
return delegate.getNamespaceCount();
}
public String getNamespacePrefix(int arg0) {
return delegate.getNamespacePrefix(arg0);
}
public String getNamespaceURI() {
return delegate.getNamespaceURI();
}
public String getNamespaceURI(int arg0) {
return delegate.getNamespaceURI(arg0);
}
public String getNamespaceURI(String arg0) {
return delegate.getNamespaceURI(arg0);
}
public String getPIData() {
return delegate.getPIData();
}
public String getPITarget() {
return delegate.getPITarget();
}
public String getPrefix() {
return delegate.getPrefix();
}
public Object getProperty(String arg0) throws IllegalArgumentException {
return delegate.getProperty(arg0);
}
public String getText() {
return delegate.getText();
}
public char[] getTextCharacters() {
return delegate.getTextCharacters();
}
public int getTextCharacters(int arg0, char[] arg1, int arg2, int arg3) throws XMLStreamException {
return delegate.getTextCharacters(arg0, arg1, arg2, arg3);
}
public int getTextLength() {
return delegate.getTextLength();
}
public int getTextStart() {
return delegate.getTextStart();
}
public String getVersion() {
return delegate.getVersion();
}
public boolean hasName() {
return delegate.hasName();
}
public boolean hasNext() throws XMLStreamException {
return delegate.hasNext();
}
public boolean hasText() {
return delegate.hasText();
}
public boolean isAttributeSpecified(int arg0) {
return delegate.isAttributeSpecified(arg0);
}
public boolean isCharacters() {
return delegate.isCharacters();
}
public boolean isEndElement() {
return delegate.isEndElement();
}
public boolean isStandalone() {
return delegate.isStandalone();
}
public boolean isStartElement() {
return delegate.isStartElement();
}
public boolean isWhiteSpace() {
return delegate.isWhiteSpace();
}
public int nextTag() throws XMLStreamException {
return delegate.nextTag();
}
public void require(int arg0, String arg1, String arg2) throws XMLStreamException {
delegate.require(arg0, arg1, arg2);
}
public boolean standaloneSet() {
return delegate.standaloneSet();
}
/**
* Dump the current event of the delegate.
*/
protected void logParserState() {
if (IS_ADV_DEBUG_ENABLED) {
int currentEvent = delegate.getEventType();
switch (currentEvent) {
case XMLStreamConstants.START_ELEMENT:
log.trace("START_ELEMENT: ");
log.trace(" QName: " + delegate.getName());
break;
case XMLStreamConstants.START_DOCUMENT:
log.trace("START_DOCUMENT: ");
break;
case XMLStreamConstants.CHARACTERS:
log.trace("CHARACTERS: ");
log.trace( "[" + delegate.getText() + "]");
break;
case XMLStreamConstants.CDATA:
log.trace("CDATA: ");
log.trace( "[" + delegate.getText() + "]");
break;
case XMLStreamConstants.END_ELEMENT:
log.trace("END_ELEMENT: ");
log.trace(" QName: " + delegate.getName());
break;
case XMLStreamConstants.END_DOCUMENT:
log.trace("END_DOCUMENT: ");
break;
case XMLStreamConstants.SPACE:
log.trace("SPACE: ");
log.trace( "[" + delegate.getText() + "]");
break;
case XMLStreamConstants.COMMENT:
log.trace("COMMENT: ");
log.trace( "[" + delegate.getText() + "]");
break;
case XMLStreamConstants.DTD:
log.trace("DTD: ");
log.trace( "[" + delegate.getText() + "]");
break;
case XMLStreamConstants.PROCESSING_INSTRUCTION:
log.trace("PROCESSING_INSTRUCTION: ");
log.trace(" [" + delegate.getPITarget() + "][" +
delegate.getPIData() + "]");
break;
case XMLStreamConstants.ENTITY_REFERENCE:
log.trace("ENTITY_REFERENCE: ");
log.trace(" " + delegate.getLocalName() + "[" +
delegate.getText() + "]");
break;
default :
log.trace("UNKNOWN_STATE: " + currentEvent);
}
}
}
public DataHandler getDataHandler(String blobcid) {
return delegate.getDataHandler(blobcid);
}
public boolean isInlineMTOM() {
return delegate.isInlineMTOM();
}
public void setInlineMTOM(boolean value) {
delegate.setInlineMTOM(value);
}
}
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