net.sf.saxon.lib

Class StandardErrorListener

java.lang.Object

net.sf.saxon.lib.StandardDiagnostics

net.sf.saxon.lib.StandardErrorListener

All Implemented Interfaces:

javax.xml.transform.ErrorListener

public class StandardErrorListener
extends StandardDiagnostics
implements javax.xml.transform.ErrorListener

StandardErrorListener is the standard error handler for XSLT and XQuery processing errors, used if no other ErrorListener is nominated.

Field Summary

Fields

Modifier and Type	Field and Description
protected Logger	logger

Fields inherited from class net.sf.saxon.lib.StandardDiagnostics

MAX_MESSAGE_LENGTH, MAX_MESSAGE_LINE_LENGTH, MIN_MESSAGE_LINE_LENGTH, TARGET_MESSAGE_LINE_LENGTH

Constructor Summary

Constructors

Constructor and Description
StandardErrorListener() Create a Standard Error Listener

Method Summary

Modifier and Type	Method and Description
java.lang.String	constructFirstLine(javax.xml.transform.TransformerException exception, XPathException xe, java.lang.String langText, java.lang.String kind) Construct the first line of the error or warning message.
java.lang.String	constructMessage(javax.xml.transform.TransformerException exception, XPathException xe, java.lang.String langText, java.lang.String kind) Construct an error or warning message.
java.lang.String	constructSecondLine(javax.xml.transform.TransformerException err, XPathException xe) Construct the second line of the error message.
void	error(javax.xml.transform.TransformerException exception) Receive notification of a recoverable error.
java.lang.CharSequence	expandSpecialCharacters(java.lang.CharSequence in) Expand any special characters appearing in a message.
void	fatalError(javax.xml.transform.TransformerException exception) Receive notification of a non-recoverable error.
java.lang.String	formatErrorCode(javax.xml.transform.TransformerException err) Format the error code contained in the supplied exception object
java.lang.String	formatErrorObject(Sequence errorObject) Get a string representation of the error object associated with the exception (this represents the final argument to fn:error, in the case of error triggered by calls on the fn:error function).
java.lang.String	formatExtraContext(Expression failingExpression, java.lang.String nearBy) Create extra context information for locating the error from knowledge of the containing expression or the nearby text retained by the tokenizer
java.lang.String	formatNestedMessages(javax.xml.transform.TransformerException err, java.lang.String message) Construct a message by combining the message from the top-level exception plus any messages associated with nested exceptions
java.lang.String	getExpandedMessage(javax.xml.transform.TransformerException err) Get a string containing the message for this exception and all contained exceptions.
java.lang.String	getLocationMessage(javax.xml.transform.TransformerException err) Get a string identifying the location of an error.
Logger	getLogger() Get the error output stream
int	getMaximumNumberOfWarnings() Get the maximum number of warnings that are reported; further warnings after this limit are silently ignored
int	getMaxOrdinaryCharacter(int max) Set the maximum codepoint value for a character to be considered non-special.
int	getStackTraceDetail() Get the level of information to be included in a stack trace when a dynamic error occurs.
boolean	isReportingWarnings() Ask whether the error listener is reporting warnings.
StandardErrorListener	makeAnother(HostLanguage hostLanguage) Make a clean copy of this ErrorListener.
protected void	outputStackTrace(Logger out, XPathContext context) Generate a stack trace for a dynamic error.
void	setLogger(Logger logger) Set output destination for error messages (default is System.err)
void	setMaximumNumberOfWarnings(int max) Set the maximum number of warnings that are reported; further warnings after this limit are silently ignored
void	setMaxOrdinaryCharacter(int max) Set the maximum codepoint value for a character to be considered non-special.
void	setStackTraceDetail(int level) Set the level of information to be included in a stack trace when a dynamic error occurs.
void	warning(javax.xml.transform.TransformerException exception) Receive notification of a warning.

Methods inherited from class net.sf.saxon.lib.StandardDiagnostics

abbreviateLocationURI, abbreviateLocationURIDefault, expandSpecialCharacters, formatListOfOffendingNodes, getInstructionName, getInstructionNameDefault, getLocationMessageText, printStackTrace, showOriginator, wordWrap

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected transient Logger logger

Constructor Detail

StandardErrorListener

public StandardErrorListener()

Create a Standard Error Listener

Method Detail

makeAnother

public StandardErrorListener makeAnother(HostLanguage hostLanguage)

Make a clean copy of this ErrorListener. This is necessary because the standard error listener is stateful (it remembers how many errors there have been)

Parameters:

hostLanguage - the host language (not used by this implementation)

Returns:

a copy of this error listener

setLogger

public void setLogger(Logger logger)

Set output destination for error messages (default is System.err)

Parameters:

logger - The Logger to use for error messages

getLogger

public Logger getLogger()

Get the error output stream

Returns:

the error output stream

setMaximumNumberOfWarnings

public void setMaximumNumberOfWarnings(int max)

Set the maximum number of warnings that are reported; further warnings after this limit are silently ignored

Parameters:

max - the maximum number of warnings output

getMaximumNumberOfWarnings

public int getMaximumNumberOfWarnings()

Get the maximum number of warnings that are reported; further warnings after this limit are silently ignored

Returns:

the maximum number of warnings output

setStackTraceDetail

public void setStackTraceDetail(int level)

Set the level of information to be included in a stack trace when a dynamic error occurs.

Parameters:

level - set to 0 (zero) for no stack trace; 1 (one) for a stack trace showing the templates and functions being executed; 2 (two) to add values of local variables and parameters (available in Saxon-EE only) Default is the maximum level available.

getStackTraceDetail

public int getStackTraceDetail()

Get the level of information to be included in a stack trace when a dynamic error occurs.

Returns:

0 (zero) for no stack trace; 1 (one) for a stack trace showing the templates and functions being executed; 2 (two) to add values of local variables and parameters (available in Saxon-EE only) Default is the maximum level available.

setMaxOrdinaryCharacter

public void setMaxOrdinaryCharacter(int max)

Set the maximum codepoint value for a character to be considered non-special. Special characters (codepoints above this value) will be expanded in hex for extra clarity in the error message.

Parameters:

max - the highest codepoint considered non-special (defaults to 255)

getMaxOrdinaryCharacter

public int getMaxOrdinaryCharacter(int max)

Set the maximum codepoint value for a character to be considered non-special. Special characters (codepoints above this value) will be expanded in hex for extra clarity in the error message.

Parameters:

max - the highest codepoint considered non-special (defaults to 255)

warning

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

Receive notification of a warning.

Transformers 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.

See Also:

TransformerException

isReportingWarnings

public boolean isReportingWarnings()

Ask whether the error listener is reporting warnings. (If it isn't, the caller can save the effort of constructing one; which is significant because it's represented by an exception, and constructing exceptions is expensive).

Returns:

true if the error listener is ignoring warnings, perhaps because the threshold on the number of warnings has been exceeded.

error

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

Receive notification of a recoverable error.

The transformer 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.

The action of the standard error listener depends on the recovery policy that has been set, which may be one of RECOVER_SILENTLY, RECOVER_WITH_WARNING, or DO_NOT_RECOVER

Specified by:

error in interface javax.xml.transform.ErrorListener

Parameters:

exception - The error information encapsulated in a transformer exception.

See Also:

TransformerException

fatalError

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

Receive notification of a non-recoverable error.

The application must assume that the transformation cannot continue after the Transformer has invoked this method, and should continue (if at all) only to collect addition error messages. In fact, Transformers are free to stop reporting events once this method has been invoked.

Specified by:

fatalError in interface javax.xml.transform.ErrorListener

Parameters:

exception - The error information encapsulated in a transformer exception.

constructMessage

public java.lang.String constructMessage(javax.xml.transform.TransformerException exception,
                                         XPathException xe,
                                         java.lang.String langText,
                                         java.lang.String kind)

Construct an error or warning message.

The default implementation outputs a two-line message: the first line is obtained by calling constructFirstLine(TransformerException, XPathException, String, String), the second by calling constructSecondLine(TransformerException, XPathException); these are concatenated with a newline and two spaces separating them.

Parameters:

exception - the exception originally reported to the ErrorListener

xe - the result of converting the exception to an XPathException (possibly null). This may be the original exception, or an XPathException nested within it.

langText - a string such as "in expression" or "in query" identifying the kind of construct that is in error

kind - the kind of error, for example "Syntax error", "Static error", "Type error"

Returns:

the constructed message

constructFirstLine

public java.lang.String constructFirstLine(javax.xml.transform.TransformerException exception,
                                           XPathException xe,
                                           java.lang.String langText,
                                           java.lang.String kind)

Construct the first line of the error or warning message. This typically contains information about the kind of error that occurred, and the location where it occurred

Parameters:

exception - the exception originally reported to the ErrorListener

xe - the result of converting the exception to an XPathException (possibly null). This may be the original exception, or an XPathException nested within it.

langText - a string such as "in expression" or "in query" identifying the kind of construct that is in error

kind - the kind of error, for example "Syntax error", "Static error", "Type error"

Returns:

the constructed message

formatExtraContext

public java.lang.String formatExtraContext(Expression failingExpression,
                                           java.lang.String nearBy)

Create extra context information for locating the error from knowledge of the containing expression or the nearby text retained by the tokenizer

Parameters:

failingExpression - the subexpression in which the failure occurs (possibly null)

nearBy - text from the input buffer near the error, retained by the tokenizer (possible null)

Returns:

a message with extra context information, or an empty string if nothing is available.

constructSecondLine

public java.lang.String constructSecondLine(javax.xml.transform.TransformerException err,
                                            XPathException xe)

Construct the second line of the error message. This contains the error code, error object (if applicable) and the textual message.

The default implementation depends on the kind of exception:

• For a ValidationException, it constructs a message containing the error message together with explanations of which XSD Schema constraint was violated;
• For other exceptions, it returns a string comprising two characters of indentation, followed by the result of calling getExpandedMessage(TransformerException) and then formatting the result using StandardDiagnostics.wordWrap(String) and expandSpecialCharacters(CharSequence).

Parameters:

err - the original reported exception

Returns:

the string to be used as the second line of the error message

outputStackTrace

protected void outputStackTrace(Logger out,
                                XPathContext context)

Generate a stack trace for a dynamic error. The default implementation calls StandardDiagnostics.printStackTrace(XPathContext, Logger, int) supplying as the third argument the current setting of setStackTraceDetail(int), which defaults to 2.

Parameters:

out - the destination for the stack trace

context - the context (which holds the information to be output)

getLocationMessage

public java.lang.String getLocationMessage(javax.xml.transform.TransformerException err)

Get a string identifying the location of an error. The default implementation first tries to get a SourceLocator object from this exception or from any nested exception, and then, if a SourceLocator is found, calls StandardDiagnostics.getLocationMessageText(SourceLocator) to format the location information.

Parameters:

err - the exception containing the location information

Returns:

a message string describing the location

getExpandedMessage

public java.lang.String getExpandedMessage(javax.xml.transform.TransformerException err)

Get a string containing the message for this exception and all contained exceptions.

The default implementation outputs the concatenation (with space-separation) of:

• The error code, formatted using formatErrorCode(TransformerException)
• The error object, formatted using formatErrorObject(Sequence) (whose default implementation outputs nothing)
• The message associated with this exception, and with all nested exceptions, formatted using formatNestedMessages(TransformerException, String)

Parameters:

err - the exception containing the required information

Returns:

a message that concatenates the message of this exception with its contained exceptions, also including information about the error code and location.

formatNestedMessages

public java.lang.String formatNestedMessages(javax.xml.transform.TransformerException err,
                                             java.lang.String message)

Construct a message by combining the message from the top-level exception plus any messages associated with nested exceptions

The default implementation outputs the supplied message, followed by the messages from any nested (contained) exceptions, colon-separated, with some attempt to remove duplicated messages and certain redundant message prefixes (such as "net.sf.saxon.trans.XPathException: " and "TRaX Transform Exception")

Parameters:

err - the original reported exception

message - the message as constructed so far, containing the error code, error object, and the message from the original reported exception

Returns:

an expanded message containing the supplied message followed by messages from any contained exceptions.

formatErrorCode

public java.lang.String formatErrorCode(javax.xml.transform.TransformerException err)

Format the error code contained in the supplied exception object

Parameters:

err - the exception object. The default implementation looks for an error code both in this object (if it is an XPathException) or in any wrapped XPathException. The default implementation ignores the namespace part of the error code (which is in general a QName) if it is the standard namespace NamespaceConstant.ERR; otherwise it displays the code in the format prefix:localName.

Returns:

a string representation of the error code

formatErrorObject

public java.lang.String formatErrorObject(Sequence errorObject)

Get a string representation of the error object associated with the exception (this represents the final argument to fn:error, in the case of error triggered by calls on the fn:error function). The standard implementation returns null, meaning that the error object is not displayed; but the method can be overridden in a subclass to create a custom display of the error object, which is then appended to the message text.

Parameters:

errorObject - the error object passed as the last argument to fn:error. Note: this method is not called if the error object is absent/null

Returns:

a string representation of the error object to be appended to the message, or null if no output of the error object is required

expandSpecialCharacters

public java.lang.CharSequence expandSpecialCharacters(java.lang.CharSequence in)

Expand any special characters appearing in a message. Special characters will be output as themselves, followed by a hex codepoint in the form [xHHHHH]. Characters are considered special if they have a codepoint above the value set using setMaxOrdinaryCharacter(int). The default implementation returns the message unchanged if the registered Logger is unicode-aware.

This method is provided because a number of operating systems cannot display arbitrary Unicode characters on the system console, or cannot do so unless the console has been specially configured. The simplest way to prevent messages being expanded in this way is to mark the logger as being unicode-aware.

If messages are expanded, then they will be expanded using the method StandardDiagnostics.expandSpecialCharacters(CharSequence, int), which can be overridden to define the actual format in which special characters are displayed.

Parameters:

in - the message to be expanded

Returns:

the expanded message