SafeXMLStreamReader (Axiom 1.2.8 API)

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org.apache.axiom.om.impl.builder
Class SafeXMLStreamReader

java.lang.Object
  javax.xml.stream.util.StreamReaderDelegate
      org.apache.axiom.om.impl.builder.SafeXMLStreamReader

All Implemented Interfaces:: javax.xml.stream.XMLStreamConstants, javax.xml.stream.XMLStreamReader

public class SafeXMLStreamReader
extends javax.xml.stream.util.StreamReaderDelegate
extends javax.xml.stream.util.StreamReaderDelegate

XMLStreamReader wrapper that prevents access to the underlying parser after the first error occurs.

Usually, code that uses StAX directly just stops processing of an XML document once the first parsing error has been reported. However, since Axiom uses deferred parsing, and client code accesses the XML infoset using an object model, things are more complicated. Indeed, if the XML document is not well formed, the corresponding error might be reported as a runtime exception by any call to a method of an OM node.

Typically the client code will have some error handling that will intercept runtime exceptions and take appropriate action. Very often this error handling code might want to access the object model again, for example to log the request that caused the failure. This causes no problem except if the runtime exception was caused by a parsing error, in which case Axiom would again try to pull events from the parser.

This would lead to a situation where Axiom accesses a parser that has reported a parsing error before. While one would expect that after a first error reported by the parser, all subsequent invocations of the parser will fail, this is not the case for all parsers (at least not in all situations). Instead, the parser might be left in an inconsistent state after the error. E.g. WSCOMMONS-372 describes a case where Woodstox encounters an error in XMLStreamReader.getText() but continues to return (incorrect) events afterwards. The explanation for this behaviour might be that the situation described here is quite uncommon when StAX is used directly (i.e. not through Axiom).

This class provides a simple way to prevent this type of issue by wrapping the underlying parser implementation. After the first parsing error occurs, the wrapper prevents any call to XMLStreamReader.next() and similar methods on the underlying parser. Any attempt to do so will immediately result in an error.

Field Summary

Fields inherited from interface javax.xml.stream.XMLStreamConstants
`ATTRIBUTE, CDATA, CHARACTERS, COMMENT, DTD, END_DOCUMENT, END_ELEMENT, ENTITY_DECLARATION, ENTITY_REFERENCE, NAMESPACE, NOTATION_DECLARATION, PROCESSING_INSTRUCTION, SPACE, START_DOCUMENT, START_ELEMENT`

Constructor Summary
`SafeXMLStreamReader(javax.xml.stream.XMLStreamReader reader)`

Method Summary
`String`	`getElementText()`
`String`	`getPIData()`
`String`	`getText()`
`char[]`	`getTextCharacters()`
`int`	`getTextCharacters(int sourceStart, char[] target, int targetStart, int length)`
`int`	`getTextLength()`
`int`	`getTextStart()`
`boolean`	`hasNext()`
`int`	`next()`
`int`	`nextTag()`

Methods inherited from class javax.xml.stream.util.StreamReaderDelegate
close, getAttributeCount, getAttributeLocalName, getAttributeName, getAttributeNamespace, getAttributePrefix, getAttributeType, getAttributeValue, getAttributeValue, getCharacterEncodingScheme, getEncoding, getEventType, getLocalName, getLocation, getName, getNamespaceContext, getNamespaceCount, getNamespacePrefix, getNamespaceURI, getNamespaceURI, getNamespaceURI, getParent, getPITarget, getPrefix, getProperty, getVersion, hasName, hasText, isAttributeSpecified, isCharacters, isEndElement, isStandalone, isStartElement, isWhiteSpace, require, setParent, standaloneSet

Methods inherited from class javax.xml.stream.util.StreamReaderDelegate

close, getAttributeCount, getAttributeLocalName, getAttributeName, getAttributeNamespace, getAttributePrefix, getAttributeType, getAttributeValue, getAttributeValue, getCharacterEncodingScheme, getEncoding, getEventType, getLocalName, getLocation, getName, getNamespaceContext, getNamespaceCount, getNamespacePrefix, getNamespaceURI, getNamespaceURI, getNamespaceURI, getParent, getPITarget, getPrefix, getProperty, getVersion, hasName, hasText, isAttributeSpecified, isCharacters, isEndElement, isStandalone, isStartElement, isWhiteSpace, require, setParent, standaloneSet

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail