cascading.tap.hadoop
Class TemplateTap

java.lang.Object
  cascading.tap.Tap<Config,Void,Output>
      cascading.tap.SinkTap<Config,Output>
          cascading.tap.BaseTemplateTap<JobConf,OutputCollector>
              cascading.tap.hadoop.TemplateTap

All Implemented Interfaces:

FlowElement, Serializable

Deprecated.

@Deprecated
public class TemplateTap
extends BaseTemplateTap<JobConf,OutputCollector>

Class TemplateTap can be used to write tuple streams out to sub-directories based on the values in the Tuple instance.

The constructor takes a Hfs Tap and a Formatter format syntax String. This allows Tuple values at given positions to be used as directory names. Note that Hadoop can only sink to directories, and all files in those directories are "part-xxxxx" files.

openTapsThreshold limits the number of open files to be output to. This value defaults to 300 files. Each time the threshold is exceeded, 10% of the least recently used open files will be closed.

TemplateTap will populate a given pathTemplate without regard to case of the values being used. Thus the resulting paths 2012/June/ and 2012/june/ will likely result in two open files into the same location. Forcing the case to be consistent with an upstream Function is recommended, see ExpressionFunction.

Though Hadoop has no mechanism to prevent simultaneous writes to a directory from multiple jobs, it doesn't mean its safe to do so. Same is true with the TemplateTap. Interleaving writes to a common parent (root) directory across multiple flows will very likely lead to data loss.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class cascading.tap.BaseTemplateTap

BaseTemplateTap.Counters, BaseTemplateTap.TemplateScheme<Config,Output>

Field Summary

Fields inherited from class cascading.tap.BaseTemplateTap

keepParentOnDelete, OPEN_TAPS_THRESHOLD_DEFAULT, openTapsThreshold, parent, pathTemplate

Constructor Summary

TemplateTap(Hfs parent, String pathTemplate)
Deprecated. Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String.

TemplateTap(Hfs parent, String pathTemplate, Fields pathFields)
Deprecated. Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String.

TemplateTap(Hfs parent, String pathTemplate, Fields pathFields, int openTapsThreshold)
Deprecated. Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String.

TemplateTap(Hfs parent, String pathTemplate, Fields pathFields, SinkMode sinkMode)
Deprecated. Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String.

TemplateTap(Hfs parent, String pathTemplate, Fields pathFields, SinkMode sinkMode, boolean keepParentOnDelete)
Deprecated. Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String.

TemplateTap(Hfs parent, String pathTemplate, Fields pathFields, SinkMode sinkMode, boolean keepParentOnDelete, int openTapsThreshold)
Deprecated. Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String.

TemplateTap(Hfs parent, String pathTemplate, int openTapsThreshold)
Deprecated. Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String.

TemplateTap(Hfs parent, String pathTemplate, SinkMode sinkMode)
Deprecated. Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String.

TemplateTap(Hfs parent, String pathTemplate, SinkMode sinkMode, boolean keepParentOnDelete)
Deprecated. Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String.

TemplateTap(Hfs parent, String pathTemplate, SinkMode sinkMode, boolean keepParentOnDelete, int openTapsThreshold)
Deprecated. Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String.

Method Summary

protected TupleEntrySchemeCollector

createTupleEntrySchemeCollector(FlowProcess<JobConf> flowProcess, Tap parent, String path) Deprecated.

Methods inherited from class cascading.tap.BaseTemplateTap

commitResource, createResource, deleteResource, equals, getIdentifier, getModifiedTime, getOpenTapsThreshold, getParent, getPathTemplate, hashCode, openForWrite, resourceExists, rollbackResource, toString

Methods inherited from class cascading.tap.SinkTap

getSourceFields, isSource, openForRead, sourceConfInit

Methods inherited from class cascading.tap.Tap

createResource, deleteResource, flowConfInit, getConfigDef, getFullIdentifier, getFullIdentifier, getModifiedTime, getScheme, getSinkFields, getSinkMode, getStepConfigDef, getTrace, hasConfigDef, hasStepConfigDef, id, isEquivalentTo, isKeep, isReplace, isSink, isTemporary, isUpdate, openForRead, openForWrite, outgoingScopeFor, presentSinkFields, presentSourceFields, resolveIncomingOperationArgumentFields, resolveIncomingOperationPassThroughFields, resourceExists, retrieveSinkFields, retrieveSourceFields, setScheme, sinkConfInit, taps

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

TemplateTap

@ConstructorProperties(value={"parent","pathTemplate"})
public TemplateTap(Hfs parent,
                                              String pathTemplate)

Deprecated.

Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String.

Parameters:

parent - of type Tap

pathTemplate - of type String

TemplateTap

@ConstructorProperties(value={"parent","pathTemplate","openTapsThreshold"})
public TemplateTap(Hfs parent,
                                              String pathTemplate,
                                              int openTapsThreshold)

Deprecated.

Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String.

openTapsThreshold limits the number of open files to be output to.

Parameters:

parent - of type Hfs

pathTemplate - of type String

openTapsThreshold - of type int

TemplateTap

@ConstructorProperties(value={"parent","pathTemplate","sinkMode"})
public TemplateTap(Hfs parent,
                                              String pathTemplate,
                                              SinkMode sinkMode)

Deprecated.

Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String.

Parameters:

parent - of type Tap

pathTemplate - of type String

sinkMode - of type SinkMode

TemplateTap

@ConstructorProperties(value={"parent","pathTemplate","sinkMode","keepParentOnDelete"})
public TemplateTap(Hfs parent,
                                              String pathTemplate,
                                              SinkMode sinkMode,
                                              boolean keepParentOnDelete)

Deprecated.

Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String.

keepParentOnDelete, when set to true, prevents the parent Tap from being deleted when BaseTemplateTap.deleteResource(Object) is called, typically an issue when used inside a Cascade.

Parameters:

parent - of type Tap

pathTemplate - of type String

sinkMode - of type SinkMode

keepParentOnDelete - of type boolean

TemplateTap

@ConstructorProperties(value={"parent","pathTemplate","sinkMode","keepParentOnDelete","openTapsThreshold"})
public TemplateTap(Hfs parent,
                                              String pathTemplate,
                                              SinkMode sinkMode,
                                              boolean keepParentOnDelete,
                                              int openTapsThreshold)

Deprecated.

Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String.

keepParentOnDelete, when set to true, prevents the parent Tap from being deleted when BaseTemplateTap.deleteResource(Object) is called, typically an issue when used inside a Cascade.

openTapsThreshold limits the number of open files to be output to.

Parameters:

parent - of type Tap

pathTemplate - of type String

sinkMode - of type SinkMode

keepParentOnDelete - of type boolean

openTapsThreshold - of type int

TemplateTap

@ConstructorProperties(value={"parent","pathTemplate","pathFields"})
public TemplateTap(Hfs parent,
                                              String pathTemplate,
                                              Fields pathFields)

Deprecated.

Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String. The pathFields is a selector that selects and orders the fields to be used in the given pathTemplate.

This constructor also allows the sinkFields of the parent Tap to be independent of the pathFields. Thus allowing data not in the result file to be used in the template path name.

Parameters:

parent - of type Tap

pathTemplate - of type String

pathFields - of type Fields

TemplateTap

@ConstructorProperties(value={"parent","pathTemplate","pathFields","openTapsThreshold"})
public TemplateTap(Hfs parent,
                                              String pathTemplate,
                                              Fields pathFields,
                                              int openTapsThreshold)

Deprecated.

Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String. The pathFields is a selector that selects and orders the fields to be used in the given pathTemplate.

This constructor also allows the sinkFields of the parent Tap to be independent of the pathFields. Thus allowing data not in the result file to be used in the template path name.

openTapsThreshold limits the number of open files to be output to.

Parameters:

parent - of type Hfs

pathTemplate - of type String

pathFields - of type Fields

openTapsThreshold - of type int

TemplateTap

@ConstructorProperties(value={"parent","pathTemplate","pathFields","sinkMode"})
public TemplateTap(Hfs parent,
                                              String pathTemplate,
                                              Fields pathFields,
                                              SinkMode sinkMode)

Deprecated.

Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String. The pathFields is a selector that selects and orders the fields to be used in the given pathTemplate.

This constructor also allows the sinkFields of the parent Tap to be independent of the pathFields. Thus allowing data not in the result file to be used in the template path name.

Parameters:

parent - of type Tap

pathTemplate - of type String

pathFields - of type Fields

sinkMode - of type SinkMode

TemplateTap

@ConstructorProperties(value={"parent","pathTemplate","pathFields","sinkMode","keepParentOnDelete"})
public TemplateTap(Hfs parent,
                                              String pathTemplate,
                                              Fields pathFields,
                                              SinkMode sinkMode,
                                              boolean keepParentOnDelete)

Deprecated.

Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String. The pathFields is a selector that selects and orders the fields to be used in the given pathTemplate.

This constructor also allows the sinkFields of the parent Tap to be independent of the pathFields. Thus allowing data not in the result file to be used in the template path name.

keepParentOnDelete, when set to true, prevents the parent Tap from being deleted when BaseTemplateTap.deleteResource(Object) is called, typically an issue when used inside a Cascade.

Parameters:

parent - of type Tap

pathTemplate - of type String

pathFields - of type Fields

sinkMode - of type SinkMode

keepParentOnDelete - of type boolean

TemplateTap

@ConstructorProperties(value={"parent","pathTemplate","pathFields","sinkMode","keepParentOnDelete","openTapsThreshold"})
public TemplateTap(Hfs parent,
                                              String pathTemplate,
                                              Fields pathFields,
                                              SinkMode sinkMode,
                                              boolean keepParentOnDelete,
                                              int openTapsThreshold)

Deprecated.

Constructor TemplateTap creates a new TemplateTap instance using the given parent Hfs Tap as the base path and default Scheme, and the pathTemplate as the Formatter format String. The pathFields is a selector that selects and orders the fields to be used in the given pathTemplate.

This constructor also allows the sinkFields of the parent Tap to be independent of the pathFields. Thus allowing data not in the result file to be used in the template path name.

keepParentOnDelete, when set to true, prevents the parent Tap from being deleted when BaseTemplateTap.deleteResource(Object) is called, typically an issue when used inside a Cascade.

openTapsThreshold limits the number of open files to be output to.

Parameters:

parent - of type Hfs

pathTemplate - of type String

pathFields - of type Fields

sinkMode - of type SinkMode

keepParentOnDelete - of type boolean

openTapsThreshold - of type int

Method Detail

createTupleEntrySchemeCollector

protected TupleEntrySchemeCollector createTupleEntrySchemeCollector(FlowProcess<JobConf> flowProcess,
                                                                    Tap parent,
                                                                    String path)
                                                             throws IOException

Deprecated.

Specified by:

createTupleEntrySchemeCollector in class BaseTemplateTap<JobConf,OutputCollector>

Throws:

IOException