cascading.tap
Class TrapProps

java.lang.Object
  cascading.property.Props
      cascading.tap.TrapProps

public class TrapProps
extends Props

Class TrapProps is a fluent helper class to set properties which control the behaviour of Tap instances used as traps on a given Flow.

A Tap trap is used to capture bad data that has triggered an unhandled Throwable within a Cascading Operation or Tap (either as a source or sink).

When a trap captures a failure, the Tuple arguments to the Operation or Tap will be captured and the Flow will continue executing with the next Tuple in the stream. Otherwise a Flow would typically fail.

Due to the variability of data in the stream at any given point, a Tap trap should be configured with a Scheme that sinks Fields.ALL, or is guaranteed to sink known fields common to all Operations within the branch the trap has been bound too.

Optionally diagnostic information, with the given field names, may be captured along with the argument Tuple.

• element-trace - the file and line number the failed operation was instantiated
• throwable-message - the Throwable.getMessage() value
• throwable-stacktrace - the Throwable.printStackTrace() value, cleansed

By default, if the Throwable stacktrace is captured, each line of the trace will be trimmed (to remove the TAB character (\t) and each new line (\n) will be replaced with a pipe character (|).

Each value is prepended to the argument Tuple in the order given above. Since the argument Tuple may vary in size, prepending the diagnostic value deterministically allows for simple grep and sed like commands to be applied to the files.

Trap properties can be applied to a given Flow by calling Props.buildProperties() on the properties instance handed to the target FlowConnector or directly to any given Tap via the Tap.getConfigDef() using Props.setProperties(cascading.property.ConfigDef).

It should be noted that traps are not intended for 'flow control' of a data stream. They are for exceptional cases that when reached should not cause a Flow to fail. Flow control (sending known bad data down a different branch) should be part of the application. Traps capture the values that are unaccounted for and cause errors, if missing them doesn't compromise the integrity of the application.

Field Summary

static String	LOG_THROWABLE_STACK_TRACE
protected boolean	logThrowableStackTrace
static String	RECORD_ELEMENT_TRACE
static String	RECORD_THROWABLE_MESSAGE
static String	RECORD_THROWABLE_STACK_TRACE
protected boolean	recordElementTrace
protected boolean	recordThrowableMessage
protected boolean	recordThrowableStackTrace
static String	STACK_TRACE_LINE_DELIMITER
static String	STACK_TRACE_LINE_TRIM
protected String	stackTraceLineDelimiter
protected boolean	stackTraceTrimLine

Constructor Summary

TrapProps()

Method Summary

protected void	addPropertiesTo(Properties properties)
String	getStackTraceLineDelimiter()
boolean	isLogThrowableStackTrace()
boolean	isRecordElementTrace()
boolean	isRecordThrowableMessage()
boolean	isRecordThrowableStackTrace()
boolean	isStackTraceTrimLine()
TrapProps	recordAllDiagnostics() Method recordAllDiagnostics enables recording of all configurable diagnostic values.
TrapProps	setLogThrowableStackTrace(boolean logThrowableStackTrace) Method setLogThrowableStackTrace will disable logging of the Throwable stacktrace value if set to false.
TrapProps	setRecordElementTrace(boolean recordElementTrace) Method setRecordElementTrace will enable recording the element trace value if set to true.
TrapProps	setRecordThrowableMessage(boolean recordThrowableMessage) Method setRecordThrowableMessage will enable recording the Throwable message value if set to true.
TrapProps	setRecordThrowableStackTrace(boolean recordThrowableStackTrace) Method setRecordThrowableStackTrace will enable recording the Throwable stacktrace value if set to true.
TrapProps	setStackTraceLineDelimiter(String stackTraceLineDelimiter) Method setStackTraceLineDelimiter will set the text delimiter used to denote stacktrace lines.
TrapProps	setStackTraceTrimLine(boolean stackTraceTrimLine) Method setStackTraceTrimLine will disable trimming of whitespace on every recorded stacktrace line if set to false.
static TrapProps	trapProps()

Methods inherited from class cascading.property.Props

buildProperties, buildProperties, buildProperties, buildProperties, setProperties, setProperties

Methods inherited from class java.lang.Object

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

Field Detail

RECORD_ELEMENT_TRACE

public static final String RECORD_ELEMENT_TRACE

See Also:

Constant Field Values

RECORD_THROWABLE_MESSAGE

public static final String RECORD_THROWABLE_MESSAGE

See Also:

Constant Field Values

RECORD_THROWABLE_STACK_TRACE

public static final String RECORD_THROWABLE_STACK_TRACE

See Also:

Constant Field Values

LOG_THROWABLE_STACK_TRACE

public static final String LOG_THROWABLE_STACK_TRACE

See Also:

Constant Field Values

STACK_TRACE_LINE_TRIM

public static final String STACK_TRACE_LINE_TRIM

See Also:

Constant Field Values

STACK_TRACE_LINE_DELIMITER

public static final String STACK_TRACE_LINE_DELIMITER

See Also:

Constant Field Values

recordElementTrace

protected boolean recordElementTrace

recordThrowableMessage

protected boolean recordThrowableMessage

recordThrowableStackTrace

protected boolean recordThrowableStackTrace

logThrowableStackTrace

protected boolean logThrowableStackTrace

stackTraceTrimLine

protected boolean stackTraceTrimLine

stackTraceLineDelimiter

protected String stackTraceLineDelimiter

Constructor Detail

TrapProps

public TrapProps()

Method Detail

trapProps

public static TrapProps trapProps()

recordAllDiagnostics

public TrapProps recordAllDiagnostics()

Method recordAllDiagnostics enables recording of all configurable diagnostic values.

Returns:

this

isRecordElementTrace

public boolean isRecordElementTrace()

setRecordElementTrace

public TrapProps setRecordElementTrace(boolean recordElementTrace)

Method setRecordElementTrace will enable recording the element trace value if set to true.

The default is false.

Parameters:

recordElementTrace - of type boolean

Returns:

this

isRecordThrowableMessage

public boolean isRecordThrowableMessage()

setRecordThrowableMessage

public TrapProps setRecordThrowableMessage(boolean recordThrowableMessage)

Method setRecordThrowableMessage will enable recording the Throwable message value if set to true.

The default is false.

Parameters:

recordThrowableMessage - of type boolean

Returns:

this

isRecordThrowableStackTrace

public boolean isRecordThrowableStackTrace()

setRecordThrowableStackTrace

public TrapProps setRecordThrowableStackTrace(boolean recordThrowableStackTrace)

Method setRecordThrowableStackTrace will enable recording the Throwable stacktrace value if set to true.

The default is false.

Parameters:

recordThrowableStackTrace - of type boolean

Returns:

this

isLogThrowableStackTrace

public boolean isLogThrowableStackTrace()

setLogThrowableStackTrace

public TrapProps setLogThrowableStackTrace(boolean logThrowableStackTrace)

Method setLogThrowableStackTrace will disable logging of the Throwable stacktrace value if set to false.

The default is true.

Parameters:

logThrowableStackTrace - of type boolean

Returns:

this

isStackTraceTrimLine

public boolean isStackTraceTrimLine()

setStackTraceTrimLine

public TrapProps setStackTraceTrimLine(boolean stackTraceTrimLine)

Method setStackTraceTrimLine will disable trimming of whitespace on every recorded stacktrace line if set to false.

The default is true.

Parameters:

stackTraceTrimLine - of type boolean

Returns:

this

getStackTraceLineDelimiter

public String getStackTraceLineDelimiter()

setStackTraceLineDelimiter

public TrapProps setStackTraceLineDelimiter(String stackTraceLineDelimiter)

Method setStackTraceLineDelimiter will set the text delimiter used to denote stacktrace lines.

The default is | (the pipe character).

Parameters:

stackTraceLineDelimiter - of type boolean

Returns:

this

addPropertiesTo

protected void addPropertiesTo(Properties properties)

Specified by:

addPropertiesTo in class Props