org.apache.xml.utils
Class ListingErrorHandler

java.lang.Object
  org.apache.xml.utils.ListingErrorHandler

All Implemented Interfaces:

org.xml.sax.ErrorHandler, javax.xml.transform.ErrorListener

public class ListingErrorHandler

extends Object

implements org.xml.sax.ErrorHandler, javax.xml.transform.ErrorListener

Sample implementation of similar SAX ErrorHandler and JAXP ErrorListener.

This implementation is suitable for various use cases, and provides some basic configuration API's as well to control when we re-throw errors, etc.

Author:

shane_curcuru@us.ibm.com

Field Summary

protected PrintWriter	m_pw
protected boolean	throwOnError If we should throw exception on errors; default:true.
protected boolean	throwOnFatalError If we should throw exception on fatalErrors; default:true.
protected boolean	throwOnWarning If we should throw exception on warnings; default:false.

Constructor Summary

ListingErrorHandler()
Constructor ListingErrorHandler; uses System.err.

ListingErrorHandler(PrintWriter pw)
Constructor ListingErrorHandler; user-supplied PrintWriter.

Method Summary

void	error(org.xml.sax.SAXParseException exception) Receive notification of a recoverable error.
void	error(javax.xml.transform.TransformerException exception) Receive notification of a recoverable error.
void	fatalError(org.xml.sax.SAXParseException exception) Receive notification of a non-recoverable error.
void	fatalError(javax.xml.transform.TransformerException exception) Receive notification of a non-recoverable error.
protected static String	getSourceLine(String sourceUrl, int lineNum) Return the specific source line that caused the exception, if possible to load it; allow exceptions to be thrown.
boolean	getThrowOnError() User-settable behavior: when to re-throw exceptions.
boolean	getThrowOnFatalError() User-settable behavior: when to re-throw exceptions.
boolean	getThrowOnWarning() User-settable behavior: when to re-throw exceptions.
static void	logExceptionLocation(PrintWriter pw, Throwable exception) Print out location information about the exception.
static void	logSourceLine(PrintWriter pw, javax.xml.transform.SourceLocator locator) Print out the specific source line that caused the exception, if possible to load it.
void	setThrowOnError(boolean b) User-settable behavior: when to re-throw exceptions.
void	setThrowOnFatalError(boolean b) User-settable behavior: when to re-throw exceptions.
void	setThrowOnWarning(boolean b) User-settable behavior: when to re-throw exceptions.
void	warning(org.xml.sax.SAXParseException exception) Receive notification of a warning.
void	warning(javax.xml.transform.TransformerException exception) Receive notification of a warning.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

m_pw

protected PrintWriter m_pw

throwOnWarning

protected boolean throwOnWarning

If we should throw exception on warnings; default:false.

throwOnError

protected boolean throwOnError

If we should throw exception on errors; default:true.

throwOnFatalError

protected boolean throwOnFatalError

If we should throw exception on fatalErrors; default:true.

Constructor Detail

ListingErrorHandler

public ListingErrorHandler(PrintWriter pw)

Constructor ListingErrorHandler; user-supplied PrintWriter.

ListingErrorHandler

public ListingErrorHandler()

Constructor ListingErrorHandler; uses System.err.

Method Detail

warning

public void warning(org.xml.sax.SAXParseException exception)
             throws org.xml.sax.SAXException

Receive notification of a warning.

SAX parsers will use this method to report conditions that are not errors or fatal errors as defined by the XML 1.0 recommendation. The default behaviour is to take no action.

The SAX parser must continue to provide normal parsing events after invoking this method: it should still be possible for the application to process the document through to the end.

Filters may use this method to report other, non-XML warnings as well.

Specified by:

warning in interface org.xml.sax.ErrorHandler

Parameters:

exception - The warning information encapsulated in a SAX parse exception.

Throws:

org.xml.sax.SAXException - Any SAX exception, possibly wrapping another exception; only if setThrowOnWarning is true.

See Also:

SAXParseException

error

public void error(org.xml.sax.SAXParseException exception)
           throws org.xml.sax.SAXException

Receive notification of a recoverable error.

This corresponds to the definition of "error" in section 1.2 of the W3C XML 1.0 Recommendation. For example, a validating parser would use this callback to report the violation of a validity constraint. The default behaviour is to take no action.

The SAX parser must continue to provide normal parsing events after invoking this method: it should still be possible for the application to process the document through to the end. If the application cannot do so, then the parser should report a fatal error even if the XML 1.0 recommendation does not require it to do so.

Filters may use this method to report other, non-XML errors as well.

Specified by:

error in interface org.xml.sax.ErrorHandler

Parameters:

exception - The error information encapsulated in a SAX parse exception.

Throws:

org.xml.sax.SAXException - Any SAX exception, possibly wrapping another exception; only if setThrowOnErroris true.

See Also:

SAXParseException

fatalError

public void fatalError(org.xml.sax.SAXParseException exception)
                throws org.xml.sax.SAXException

Receive notification of a non-recoverable error.

This corresponds to the definition of "fatal error" in section 1.2 of the W3C XML 1.0 Recommendation. For example, a parser would use this callback to report the violation of a well-formedness constraint.

The application must assume that the document is unusable after the parser has invoked this method, and should continue (if at all) only for the sake of collecting addition error messages: in fact, SAX parsers are free to stop reporting any other events once this method has been invoked.

Specified by:

fatalError in interface org.xml.sax.ErrorHandler

Parameters:

exception - The error information encapsulated in a SAX parse exception.

Throws:

org.xml.sax.SAXException - Any SAX exception, possibly wrapping another exception; only if setThrowOnFatalError is true.

See Also:

SAXParseException

warning

public void warning(javax.xml.transform.TransformerException exception)
             throws javax.xml.transform.TransformerException

Receive notification of a warning.

Transformer can use this method to report conditions that are not errors or fatal errors. The default behaviour is to take no action.

After invoking this method, the Transformer must continue with the transformation. It should still be possible for the application to process the document through to the end.

Specified by:

warning in interface javax.xml.transform.ErrorListener

Parameters:

exception - The warning information encapsulated in a transformer exception.

Throws:

javax.xml.transform.TransformerException - only if setThrowOnWarning is true.

See Also:

TransformerException

error

public void error(javax.xml.transform.TransformerException exception)
           throws javax.xml.transform.TransformerException

Receive notification of a recoverable error.

The transformer must continue to try and provide normal transformation after invoking this method. It should still be possible for the application to process the document through to the end if no other errors are encountered.

Specified by:

error in interface javax.xml.transform.ErrorListener

Parameters:

exception - The error information encapsulated in a transformer exception.

Throws:

javax.xml.transform.TransformerException - only if setThrowOnError is true.

See Also:

TransformerException

fatalError

public void fatalError(javax.xml.transform.TransformerException exception)
                throws javax.xml.transform.TransformerException

Receive notification of a non-recoverable error.

The transformer must continue to try and provide normal transformation after invoking this method. It should still be possible for the application to process the document through to the end if no other errors are encountered, but there is no guarantee that the output will be useable.

Specified by:

fatalError in interface javax.xml.transform.ErrorListener

Parameters:

exception - The error information encapsulated in a transformer exception.

Throws:

javax.xml.transform.TransformerException - only if setThrowOnError is true.

See Also:

TransformerException

logExceptionLocation

public static void logExceptionLocation(PrintWriter pw,
                                        Throwable exception)

Print out location information about the exception. Cribbed from DefaultErrorHandler.printLocation()

Parameters:

pw - PrintWriter to send output to

exception - TransformerException or SAXParseException to log information about

logSourceLine

public static void logSourceLine(PrintWriter pw,
                                 javax.xml.transform.SourceLocator locator)

Print out the specific source line that caused the exception, if possible to load it.

Parameters:

pw - PrintWriter to send output to

locator - Xalan wrapper for either a JAXP or a SAX source location object

getSourceLine

protected static String getSourceLine(String sourceUrl,
                                      int lineNum)
                               throws Exception

Return the specific source line that caused the exception, if possible to load it; allow exceptions to be thrown.

Throws:

Exception

setThrowOnWarning

public void setThrowOnWarning(boolean b)

User-settable behavior: when to re-throw exceptions.

This allows per-instance configuration of ListingErrorHandlers. You can ask us to either throw an exception when we're called for various warning / error / fatalErrors, or simply log them and continue.

getThrowOnWarning

public boolean getThrowOnWarning()

User-settable behavior: when to re-throw exceptions.

Returns:

if we throw an exception on warnings

setThrowOnError

public void setThrowOnError(boolean b)

User-settable behavior: when to re-throw exceptions.

This allows per-instance configuration of ListingErrorHandlers. You can ask us to either throw an exception when we're called for various warning / error / fatalErrors, or simply log them and continue.

Note that the behavior of many parsers/transformers after an error is not necessarily defined!

getThrowOnError

public boolean getThrowOnError()

User-settable behavior: when to re-throw exceptions.

Returns:

if we throw an exception on errors

setThrowOnFatalError

public void setThrowOnFatalError(boolean b)

User-settable behavior: when to re-throw exceptions.

This allows per-instance configuration of ListingErrorHandlers. You can ask us to either throw an exception when we're called for various warning / error / fatalErrors, or simply log them and continue.

Note that the behavior of many parsers/transformers after a fatalError is not necessarily defined, most products will probably barf if you continue.

getThrowOnFatalError

public boolean getThrowOnFatalError()

User-settable behavior: when to re-throw exceptions.

Returns:

if we throw an exception on fatalErrors