| /* |
| * 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.debug; |
| |
| import org.apache.axiom.util.stax.wrapper.XMLStreamReaderWrapper; |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| import javax.xml.namespace.QName; |
| import javax.xml.stream.XMLStreamConstants; |
| import javax.xml.stream.XMLStreamException; |
| import javax.xml.stream.XMLStreamReader; |
| |
| import java.util.Stack; |
| |
| // TODO: this needs reformatting; the (generated) Javadoc is unreadable! |
| /** |
| * There are several places in the code where events are passed from |
| * a source to a consumer using XMLStreamReader events. |
| * |
| * XMLStreamReader (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. |
| * |
| * XMLStreamReader (impl)--> XMLStreamReaderValiator-> consumer of XMLStreamReader events |
| * |
| * |
| * In the initial version, the XMStreamValidator ensures that the start element events match the |
| * end element events. |
| */ |
| public class XMLStreamReaderValidator extends XMLStreamReaderWrapper { |
| |
| private static final Log log = LogFactory.getLog(XMLStreamReaderValidator.class); |
| private static boolean IS_ADV_DEBUG_ENABLED = false; // Turn this on to trace every event |
| |
| 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 XMLStreamReaderValidator(XMLStreamReader delegate, boolean throwExceptions) { |
| super(delegate); |
| this.throwExceptions = throwExceptions; |
| } |
| |
| |
| public int next() throws XMLStreamException { |
| int event = super.next(); |
| trackEvent(event); |
| return event; |
| } |
| |
| public String getElementText() throws XMLStreamException { |
| String text = super.getElementText(); |
| trackEvent(END_ELEMENT); |
| return text; |
| } |
| |
| public int nextTag() throws XMLStreamException { |
| int event = super.nextTag(); |
| trackEvent(event); |
| return event; |
| } |
| |
| private void trackEvent(int event) throws XMLStreamException { |
| 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(super.getName()); |
| break; |
| case XMLStreamConstants.END_ELEMENT: |
| QName delegateQName = super.getName(); |
| if (stack.isEmpty()) { |
| reportError("An END_ELEMENT event for " + delegateQName + |
| " was encountered, but the START_ELEMENT stack is empty."); |
| } else { |
| QName expectedQName = (QName) stack.pop(); |
| |
| if (!expectedQName.equals(delegateQName)) { |
| reportError("An END_ELEMENT event for " + delegateQName + |
| " was encountered, but this doesn't match the corresponding START_ELEMENT " + |
| expectedQName + " event."); |
| } |
| } |
| break; |
| case XMLStreamConstants.END_DOCUMENT: |
| if (!stack.isEmpty()) { |
| reportError("An unexpected END_DOCUMENT event was encountered; element stack: " + stack); |
| } |
| break; |
| default : |
| |
| } |
| } |
| |
| private void reportError(String message) throws XMLStreamException { |
| log.debug(message); |
| if (throwExceptions) { |
| throw new XMLStreamException(message); |
| } |
| } |
| |
| /** |
| * Dump the current event of the delegate. |
| */ |
| protected void logParserState() { |
| if (IS_ADV_DEBUG_ENABLED) { |
| int currentEvent = super.getEventType(); |
| |
| switch (currentEvent) { |
| case XMLStreamConstants.START_ELEMENT: |
| log.trace("START_ELEMENT: "); |
| log.trace(" QName: " + super.getName()); |
| break; |
| case XMLStreamConstants.START_DOCUMENT: |
| log.trace("START_DOCUMENT: "); |
| break; |
| case XMLStreamConstants.CHARACTERS: |
| log.trace("CHARACTERS: "); |
| log.trace( "[" + super.getText() + "]"); |
| break; |
| case XMLStreamConstants.CDATA: |
| log.trace("CDATA: "); |
| log.trace( "[" + super.getText() + "]"); |
| break; |
| case XMLStreamConstants.END_ELEMENT: |
| log.trace("END_ELEMENT: "); |
| log.trace(" QName: " + super.getName()); |
| break; |
| case XMLStreamConstants.END_DOCUMENT: |
| log.trace("END_DOCUMENT: "); |
| break; |
| case XMLStreamConstants.SPACE: |
| log.trace("SPACE: "); |
| log.trace( "[" + super.getText() + "]"); |
| break; |
| case XMLStreamConstants.COMMENT: |
| log.trace("COMMENT: "); |
| log.trace( "[" + super.getText() + "]"); |
| break; |
| case XMLStreamConstants.DTD: |
| log.trace("DTD: "); |
| log.trace( "[" + super.getText() + "]"); |
| break; |
| case XMLStreamConstants.PROCESSING_INSTRUCTION: |
| log.trace("PROCESSING_INSTRUCTION: "); |
| log.trace(" [" + super.getPITarget() + "][" + |
| super.getPIData() + "]"); |
| break; |
| case XMLStreamConstants.ENTITY_REFERENCE: |
| log.trace("ENTITY_REFERENCE: "); |
| log.trace(" " + super.getLocalName() + "[" + |
| super.getText() + "]"); |
| break; |
| default : |
| log.trace("UNKNOWN_STATE: " + currentEvent); |
| |
| } |
| } |
| } |
| } |