tap.error

Class DefaultTAPErrorWriter

java.lang.Object

tap.error.DefaultTAPErrorWriter

All Implemented Interfaces:

ServiceErrorWriter

public class DefaultTAPErrorWriter
extends java.lang.Object
implements ServiceErrorWriter

Default implementation of ServiceErrorWriter for a TAP service.

On the contrary to the UWS standard, all errors must be formatted in VOTable. So, all errors given to this ServiceErrorWriter are formatted in VOTable using the structure defined by the IVOA. To do that, this class will use the function VOTableFormat.writeError(String, java.util.Map, java.io.PrintWriter).

The VOTableFormat will be got from the ServiceConnection using ServiceConnection.getOutputFormat(String) with "votable" as parameter. If the returned formatter is not a direct instance or an extension of VOTableFormat, a default instance of this class will be always used.

UWSExceptions and TAPExceptions may precise the HTTP error code to apply, which will be used to set the HTTP status of the response. If it is a different kind of exception, the HTTP status 500 (INTERNAL SERVER ERROR) will be used.

Besides, all exceptions except UWSException and TAPException will be logged as FATAL in the TAP context (with no event and no object). Thus the full stack trace is available to the administrator so that the error can be understood as easily and quickly as possible.

Version:

2.0 (04/2015)

Author:

Grégory Mantelet (CDS;ARI)

Field Summary

Fields

Modifier and Type	Field and Description
protected VOTableFormat	formatter Object to use to format an error message into VOTable.
protected TAPLog	logger Logger to use to report any unexpected error.
protected ServiceConnection	service Description of the TAP service using this ServiceErrorWriter.

Constructor Summary

Constructors

Constructor and Description
DefaultTAPErrorWriter(ServiceConnection service) Build an error writer for TAP.

Method Summary

Modifier and Type	Method and Description
java.lang.String	getErrorDetailsMIMEType() Get the MIME type of the error details written by ServiceErrorWriter.writeError(Throwable, ErrorSummary, UWSJob, OutputStream) in the error summary.
protected VOTableFormat	getFormatter() Get the VOTableFormat to use in order to format errors.
protected TAPLog	getLogger() Get the logger to use inside this ServiceErrorWriter.
protected void	putExceptionInfos(java.lang.Throwable t, java.util.Map<java.lang.String,java.lang.String> addInfos) Add all interesting additional information about the given exception inside the given map.
boolean	writeError(java.lang.String message, ErrorType type, int httpErrorCode, javax.servlet.http.HttpServletResponse response, javax.servlet.http.HttpServletRequest request, java.lang.String reqID, JobOwner user, java.lang.String action) Write the described error in the given response.
void	writeError(java.lang.Throwable t, ErrorSummary error, UWSJob job, java.io.OutputStream output) Write the given error in the given output stream.
boolean	writeError(java.lang.Throwable t, javax.servlet.http.HttpServletResponse response, javax.servlet.http.HttpServletRequest request, java.lang.String reqID, JobOwner user, java.lang.String action) Write the given exception in the given response.

Methods inherited from class java.lang.Object

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

Field Detail

service

protected final ServiceConnection service

Description of the TAP service using this ServiceErrorWriter.

logger

protected TAPLog logger

Logger to use to report any unexpected error. This attribute MUST NEVER be used directly, but only with its getter getLogger().

formatter

protected VOTableFormat formatter

Object to use to format an error message into VOTable. This attribute MUST NEVER be used directly, but only with its getter getFormatter().

Constructor Detail

DefaultTAPErrorWriter

public DefaultTAPErrorWriter(ServiceConnection service)
                      throws java.lang.NullPointerException

Build an error writer for TAP.

On the contrary to the UWS standard, TAP standard defines a format for error reporting. Errors should be reported as VOTable document with a defined structure. This one is well managed by VOTableFormat which is actually called by this class when an error must be written.

Parameters:

service - Description of the TAP service.

Throws:

java.lang.NullPointerException - If no service description is provided.

Method Detail

getFormatter

protected VOTableFormat getFormatter()

Get the VOTableFormat to use in order to format errors.

Note: If not yet set, the formatter of this ServiceErrorWriter is set to the formatter of VOTable results returned by the ServiceConnection. However this formatter should be a VOTableFormat instance or an extension (because the function VOTableFormat.writeError(String, java.util.Map, PrintWriter) is needed). Otherwise a default VOTableFormat instance will be created and always used by this ServiceErrorWriter.

Returns:

A VOTable formatter.

Since:

2.0

getLogger

protected TAPLog getLogger()

Get the logger to use inside this ServiceErrorWriter.

Note: If not yet set, the logger of this ServiceErrorWriter is set to the logger used by the ServiceConnection. If none is returned by the ServiceConnection, a default TAPLog instance writing logs in System.err will be created and always used by this ServiceErrorWriter.

Returns:

A logger.

Since:

2.0

writeError

public boolean writeError(java.lang.Throwable t,
                          javax.servlet.http.HttpServletResponse response,
                          javax.servlet.http.HttpServletRequest request,
                          java.lang.String reqID,
                          JobOwner user,
                          java.lang.String action)

Description copied from interface: ServiceErrorWriter

Write the given exception in the given response.

Note: If this function is called without at least an exception and an HTTP response, nothing should be done. No error may be thrown.

IMPORTANT: If any IOException occurs while writing the error in the given HttpServletResponse output stream, this function should stop and return false. In such case, the error which was supposed to be written may be logged.

Specified by:

writeError in interface ServiceErrorWriter

Parameters:

t - Exception to write/format.

response - Response in which the given exception must be written.

request - Request at the origin of the error (MAY BE NULL).

reqID - ID of the request (which let the user and the administrator identify the failed request). (MAY BE NULL if the request is not provided)

user - User which sends the given request (which generates the error) (MAY BE NULL).

action - Type/Name of the action which generates the error (MAY BE NULL).

Returns:

true if the given error message has been successfully written in the given HttpServletResponse, false otherwise.

writeError

public boolean writeError(java.lang.String message,
                          ErrorType type,
                          int httpErrorCode,
                          javax.servlet.http.HttpServletResponse response,
                          javax.servlet.http.HttpServletRequest request,
                          java.lang.String reqID,
                          JobOwner user,
                          java.lang.String action)

Description copied from interface: ServiceErrorWriter

Write the described error in the given response.

Note: If this function is called without at least a message and an HTTP response, nothing should be done. No error may be thrown.

IMPORTANT: If any IOException occurs while writing the error in the given HttpServletResponse output stream, this function should stop and return false. In such case, the error which was supposed to be written may be logged.

Specified by:

writeError in interface ServiceErrorWriter

Parameters:

message - Message to display.

type - Type of the error: FATAL or TRANSIENT.

httpErrorCode - HTTP error code (i.e. 404, 500).

response - Response in which the described error must be written.

request - Request which causes this error.

reqID - ID of the request (which let the user and the administrator identify the failed request).

user - User which sends the HTTP request.

action - Action corresponding to the given request.

Returns:

true if the given error message has been successfully written in the given HttpServletResponse, false otherwise.

writeError

public void writeError(java.lang.Throwable t,
                       ErrorSummary error,
                       UWSJob job,
                       java.io.OutputStream output)
                throws java.io.IOException

Description copied from interface: ServiceErrorWriter

Write the given error in the given output stream.

This function is used only for the error summary of a job (that's to say to report in the ../error/details parameter any error which occurs while executing a job).

Important note: The error details written in the given output MUST always have the same MIME type. This latter MUST be returned by ServiceErrorWriter.getErrorDetailsMIMEType().

Specified by:

writeError in interface ServiceErrorWriter

Parameters:

t - Error to write. If error is not null, it will be displayed instead of the message of this throwable.

error - Summary of the error. It may particularly contain a message different from the one of the given exception. In this case, it will displayed instead of the exception's message.

job - The job which fails.

output - Stream in which the error must be written.

Throws:

java.io.IOException - If there an error while writing the error in the given stream.

See Also:

ServiceErrorWriter.getErrorDetailsMIMEType()

putExceptionInfos

protected void putExceptionInfos(java.lang.Throwable t,
                                 java.util.Map<java.lang.String,java.lang.String> addInfos)

Add all interesting additional information about the given exception inside the given map.

Parameters:

t - Exception whose some details must be added inside the given map.

addInfos - Map of all additional information.

Since:

2.0

getErrorDetailsMIMEType

public java.lang.String getErrorDetailsMIMEType()

Description copied from interface: ServiceErrorWriter

Get the MIME type of the error details written by ServiceErrorWriter.writeError(Throwable, ErrorSummary, UWSJob, OutputStream) in the error summary.

Important note: If NULL is returned, the MIME type will be considered as text/plain.

Specified by:

getErrorDetailsMIMEType in interface ServiceErrorWriter

Returns:

MIME type of the error details document. If NULL, it will be considered as text/plain.

See Also:

ServiceErrorWriter.writeError(Throwable, ErrorSummary, UWSJob, OutputStream)