Tap (Cascading 3.1.2)

java.lang.Object
- cascading.tap.Tap<Config,Input,Output>

All Implemented Interfaces:

FlowElement, ScopedElement, Traceable, Serializable

Direct Known Subclasses:

BasePartitionTap, DecoratorTap, SinkTap, SourceTap
```
public abstract class Tap<Config,Input,Output>
extends Object
implements ScopedElement, FlowElement, Serializable, Traceable
```
A Tap represents the physical data source or sink in a connected Flow.
That is, a source Tap is the head end of a connected Pipe and Tuple stream, and a sink Tap is the tail end. Kinds of Tap types are used to manage files from a local disk, distributed disk, remote storage like Amazon S3, or via FTP. It simply abstracts out the complexity of connecting to these types of data sources.
A Tap takes a Scheme instance, which is used to identify the type of resource (text file, binary file, etc). A Tap is responsible for how the resource is reached.
By default when planning a Flow, Tap equality is a function of the getIdentifier() and getScheme() values. That is, two Tap instances are the same Tap instance if they sink/source the same resource and sink/source the same fields.
Some more advanced taps, like a database tap, may need to extend equality to include any filtering, like the where clause in a SQL statement so two taps reading from the same SQL table aren't considered equal.
Taps are also used to determine dependencies between two or more Flow instances when used with a Cascade. In that case the getFullIdentifier(Object) value is used and the Scheme is ignored.

See Also:
Serialized Form

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`Tap()`
`protected`	`Tap(Scheme<Config,Input,Output,?,?> scheme)`
`protected`	`Tap(Scheme<Config,Input,Output,?,?> scheme, SinkMode sinkMode)`

Method Summary

Methods
Modifier and Type	Method and Description
`boolean`	`commitResource(Config conf)` Method commitResource allows the underlying resource to be notified when all write processing is successful so that any additional cleanup or processing may be completed.
`abstract boolean`	`createResource(Config conf)` Method createResource creates the underlying resource.
`boolean`	`createResource(FlowProcess<? extends Config> flowProcess)` Method createResource creates the underlying resource.
`abstract boolean`	`deleteResource(Config conf)` Method deleteResource deletes the resource represented by this instance.
`boolean`	`deleteResource(FlowProcess<? extends Config> flowProcess)` Method deleteResource deletes the resource represented by this instance.
`boolean`	`equals(Object object)`
`void`	`flowConfInit(Flow<Config> flow)` Method flowInit allows this Tap instance to initialize itself in context of the given `Flow` instance.
`ConfigDef`	`getConfigDef()` Returns a `ConfigDef` instance that allows for local properties to be set and made available via a resulting `FlowProcess` instance when the tap is invoked.
`String`	`getFullIdentifier(Config conf)` Method getFullIdentifier returns a fully qualified resource identifier.
`String`	`getFullIdentifier(FlowProcess<? extends Config> flowProcess)` Method getFullIdentifier returns a fully qualified resource identifier.
`abstract String`	`getIdentifier()` Method getIdentifier returns a String representing the resource this Tap instance represents.
`abstract long`	`getModifiedTime(Config conf)` Method getModifiedTime returns the date this resource was last modified.
`long`	`getModifiedTime(FlowProcess<? extends Config> flowProcess)` Method getModifiedTime returns the date this resource was last modified.
`ConfigDef`	`getNodeConfigDef()` Returns a `ConfigDef` instance that allows for process level properties to be set and made available via a resulting `FlowProcess` instance when the tap is invoked.
`Scheme<Config,Input,Output,?,?>`	`getScheme()` Method getScheme returns the scheme of this Tap object.
`Fields`	`getSinkFields()` Method getSinkFields returns the sinkFields of this Tap object.
`SinkMode`	`getSinkMode()` Method getSinkMode returns the `SinkMode` }of this Tap object.
`Fields`	`getSourceFields()` Method getSourceFields returns the sourceFields of this Tap object.
`ConfigDef`	`getStepConfigDef()` Returns a `ConfigDef` instance that allows for process level properties to be set and made available via a resulting `FlowProcess` instance when the tap is invoked.
`String`	`getTrace()` Method getTrace returns a String that pinpoints the caller that created this instance.
`boolean`	`hasConfigDef()` Returns `true` if there are properties in the configDef instance.
`int`	`hashCode()`
`boolean`	`hasNodeConfigDef()` Returns `true` if there are properties in the nodeConfigDef instance.
`boolean`	`hasStepConfigDef()` Returns `true` if there are properties in the stepConfigDef instance.
`static String`	`id(Tap tap)` Creates and returns a unique ID for the given Tap, this value is cached and may be used to uniquely identify the Tap instance in properties files etc.
`boolean`	`isKeep()` Method isKeep indicates whether the resource represented by this instance should be kept if it already exists when the Flow is started.
`boolean`	`isReplace()` Method isReplace indicates whether the resource represented by this instance should be deleted if it already exists when the Flow is started.
`boolean`	`isSink()` Method isSink returns true if this Tap instance can be used as a sink.
`boolean`	`isSource()` Method isSource returns true if this Tap instance can be used as a source.
`boolean`	`isTemporary()` Method isTemporary returns true if this Tap is temporary (used for intermediate results).
`boolean`	`isUpdate()` Method isUpdate indicates whether the resource represented by this instance should be updated if it already exists.
`TupleEntryIterator`	`openForRead(FlowProcess<? extends Config> flowProcess)` Method openForRead opens the resource represented by this Tap instance for reading.
`abstract TupleEntryIterator`	`openForRead(FlowProcess<? extends Config> flowProcess, Input input)` Method openForRead opens the resource represented by this Tap instance for reading.
`TupleEntryCollector`	`openForWrite(FlowProcess<? extends Config> flowProcess)` Method openForWrite opens the resource represented by this Tap instance for writing.
`abstract TupleEntryCollector`	`openForWrite(FlowProcess<? extends Config> flowProcess, Output output)` Method openForWrite opens the resource represented by this Tap instance for writing.
`Scope`	`outgoingScopeFor(Set<Scope> incomingScopes)` Method outgoingScopeFor returns the Scope this FlowElement hands off to the next FlowElement.
`boolean`	`prepareResourceForRead(Config conf)` Method prepareResourceForRead allows the underlying resource to be notified when reading will begin.
`boolean`	`prepareResourceForWrite(Config conf)` Method prepareResourceForWrite allows the underlying resource to be notified when writing will begin.
`void`	`presentSinkFields(FlowProcess<? extends Config> flowProcess, Fields fields)`
`void`	`presentSourceFields(FlowProcess<? extends Config> flowProcess, Fields fields)`
`Fields`	`resolveIncomingOperationArgumentFields(Scope incomingScope)` Method resolveIncomingOperationArgumentFields returns the Fields outgoing from the previous FlowElement that are consumable by this FlowElement when preparing Operation arguments.
`Fields`	`resolveIncomingOperationPassThroughFields(Scope incomingScope)` Method resolveIncomingOperationPassThroughFields returns the Fields outgoing from the previous FlowElement that are consumable by this FlowElement when preparing the Pipe outgoing tuple.
`abstract boolean`	`resourceExists(Config conf)` Method resourceExists returns true if the path represented by this instance exists.
`boolean`	`resourceExists(FlowProcess<? extends Config> flowProcess)` Method resourceExists returns true if the path represented by this instance exists.
`Fields`	`retrieveSinkFields(FlowProcess<? extends Config> flowProcess)` A hook for allowing a Scheme to lazily retrieve its sink fields.
`Fields`	`retrieveSourceFields(FlowProcess<? extends Config> flowProcess)` A hook for allowing a Scheme to lazily retrieve its source fields.
`boolean`	`rollbackResource(Config conf)` Method rollbackResource allows the underlying resource to be notified when any write processing has failed or was stopped so that any cleanup may be started.
`protected void`	`setScheme(Scheme<Config,Input,Output,?,?> scheme)`
`void`	`sinkConfInit(FlowProcess<? extends Config> flowProcess, Config conf)` Method sinkConfInit initializes this instance as a sink.
`void`	`sourceConfInit(FlowProcess<? extends Config> flowProcess, Config conf)` Method sourceConfInit initializes this instance as a source.
`static Tap[]`	`taps(Tap... taps)` Convenience function to make an array of Tap instances.
`String`	`toString()`

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - Tap
```
protected Tap()
```
  - Tap
```
protected Tap(Scheme<Config,Input,Output,?,?> scheme)
```
  - Tap
```
protected Tap(Scheme<Config,Input,Output,?,?> scheme,
   SinkMode sinkMode)
```
- Method Detail
  - taps
```
public static Tap[] taps(Tap... taps)
```
    Convenience function to make an array of Tap instances.
    
    Parameters:
    taps - of type Tap
    
    Returns:
    Tap array
  - id
```
public static String id(Tap tap)
```
    Creates and returns a unique ID for the given Tap, this value is cached and may be used to uniquely identify the Tap instance in properties files etc.
    This value is generally reproducible assuming the Tap identifier and the Scheme source and sink Fields remain consistent.
    
    Parameters:
    tap - of type Tap
    
    Returns:
    of type String
  - setScheme
```
protected void setScheme(Scheme<Config,Input,Output,?,?> scheme)
```
  - getScheme
```
public Scheme<Config,Input,Output,?,?> getScheme()
```
    Method getScheme returns the scheme of this Tap object.
    
    Returns:
    the scheme (type Scheme) of this Tap object.
  - getTrace
```
public String getTrace()
```
    Description copied from interface: Traceable
    
    Method getTrace returns a String that pinpoints the caller that created this instance.
    
    Specified by:
    
    getTrace in interface Traceable
    
    Returns:
    String
  - flowConfInit
```
public void flowConfInit(Flow<Config> flow)
```
    Method flowInit allows this Tap instance to initialize itself in context of the given Flow instance. This method is guaranteed to be called before the Flow is started and the FlowListener.onStarting(cascading.flow.Flow) event is fired.
    This method will be called once per Flow, and before sourceConfInit(cascading.flow.FlowProcess, Object) and sinkConfInit(cascading.flow.FlowProcess, Object) methods.
    
    Parameters:
    flow - of type Flow
  - sourceConfInit
```
public void sourceConfInit(FlowProcess<? extends Config> flowProcess,
                  Config conf)
```
    Method sourceConfInit initializes this instance as a source.
    This method maybe called more than once if this Tap instance is used outside the scope of a Flow instance or if it participates in multiple times in a given Flow or across different Flows in a Cascade.
    In the context of a Flow, it will be called after FlowListener.onStarting(cascading.flow.Flow)
    Note that no resources or services should be modified by this method.
    
    Parameters:
    flowProcess - of type FlowProcess
    conf - of type Config
  - sinkConfInit
```
public void sinkConfInit(FlowProcess<? extends Config> flowProcess,
                Config conf)
```
    Method sinkConfInit initializes this instance as a sink.
    This method maybe called more than once if this Tap instance is used outside the scope of a Flow instance or if it participates in multiple times in a given Flow or across different Flows in a Cascade.
    Note this method will be called in context of this Tap being used as a traditional 'sink' and as a 'trap'.
    In the context of a Flow, it will be called after FlowListener.onStarting(cascading.flow.Flow)
    Note that no resources or services should be modified by this method. If this Tap instance returns true for isReplace(), then deleteResource(Object) will be called by the parent Flow.
    
    Parameters:
    flowProcess - of type FlowProcess
    conf - of type Config
  - getIdentifier
```
public abstract String getIdentifier()
```
    Method getIdentifier returns a String representing the resource this Tap instance represents.
    Often, if the tap accesses a filesystem, the identifier is nothing more than the path to the file or directory. In other cases it may be a an URL or URI representing a connection string or remote resource.
    Any two Tap instances having the same value for the identifier are considered equal.
    
    Returns:
    String
  - getSourceFields
```
public Fields getSourceFields()
```
    Method getSourceFields returns the sourceFields of this Tap object.
    
    Returns:
    the sourceFields (type Fields) of this Tap object.
  - getSinkFields
```
public Fields getSinkFields()
```
    Method getSinkFields returns the sinkFields of this Tap object.
    
    Returns:
    the sinkFields (type Fields) of this Tap object.
  - openForRead
```
public abstract TupleEntryIterator openForRead(FlowProcess<? extends Config> flowProcess,
                             Input input)
                                        throws IOException
```
    Method openForRead opens the resource represented by this Tap instance for reading.
    input value may be null, if so, sub-classes must inquire with the underlying Scheme via Scheme.sourceConfInit(cascading.flow.FlowProcess, Tap, Object) to get the proper input type and instantiate it before calling super.openForRead().
    Note the returned iterator will return the same instance of TupleEntry on every call, thus a copy must be made of either the TupleEntry or the underlying Tuple instance if they are to be stored in a Collection.
    
    Parameters:
    flowProcess - of type FlowProcess
    input - of type Input
    
    Returns:
    TupleEntryIterator
    
    Throws:
    
    IOException - when the resource cannot be opened
  - openForRead
```
public TupleEntryIterator openForRead(FlowProcess<? extends Config> flowProcess)
                               throws IOException
```
    Method openForRead opens the resource represented by this Tap instance for reading.
    Note the returned iterator will return the same instance of TupleEntry on every call, thus a copy must be made of either the TupleEntry or the underlying Tuple instance if they are to be stored in a Collection.
    
    Parameters:
    flowProcess - of type FlowProcess
    
    Returns:
    TupleEntryIterator
    
    Throws:
    
    IOException - when the resource cannot be opened
  - openForWrite
```
public abstract TupleEntryCollector openForWrite(FlowProcess<? extends Config> flowProcess,
                               Output output)
                                          throws IOException
```
    Method openForWrite opens the resource represented by this Tap instance for writing.
    This method is used internally and does not honor the SinkMode setting. If SinkMode is SinkMode.REPLACE, this call may fail. See openForWrite(cascading.flow.FlowProcess).
    output value may be null, if so, sub-classes must inquire with the underlying Scheme via Scheme.sinkConfInit(cascading.flow.FlowProcess, Tap, Object) to get the proper output type and instantiate it before calling super.openForWrite().
    
    Parameters:
    flowProcess - of type FlowProcess
    output - of type Output
    
    Returns:
    TupleEntryCollector
    
    Throws:
    
    IOException - when the resource cannot be opened
  - openForWrite
```
public TupleEntryCollector openForWrite(FlowProcess<? extends Config> flowProcess)
                                 throws IOException
```
    Method openForWrite opens the resource represented by this Tap instance for writing.
    This method is for user application use and does honor the SinkMode.REPLACE settings. That is, if SinkMode is set to SinkMode.REPLACE the underlying resource will be deleted.
    Note if SinkMode.UPDATE is set, the resource will not be deleted.
    
    Parameters:
    flowProcess - of type FlowProcess
    
    Returns:
    TupleEntryCollector
    
    Throws:
    
    IOException - when the resource cannot be opened
  - outgoingScopeFor
```
public Scope outgoingScopeFor(Set<Scope> incomingScopes)
```
    Description copied from interface: ScopedElement
    
    Method outgoingScopeFor returns the Scope this FlowElement hands off to the next FlowElement.
    
    Specified by:
    
    outgoingScopeFor in interface ScopedElement
    
    Parameters:
    incomingScopes - of type Set
    
    Returns:
    Scope
  - retrieveSourceFields
```
public Fields retrieveSourceFields(FlowProcess<? extends Config> flowProcess)
```
    A hook for allowing a Scheme to lazily retrieve its source fields.
    
    Parameters:
    flowProcess - of type FlowProcess
    
    Returns:
    the found Fields
  - presentSourceFields
```
public void presentSourceFields(FlowProcess<? extends Config> flowProcess,
                       Fields fields)
```
  - retrieveSinkFields
```
public Fields retrieveSinkFields(FlowProcess<? extends Config> flowProcess)
```
    A hook for allowing a Scheme to lazily retrieve its sink fields.
    
    Parameters:
    flowProcess - of type FlowProcess
    
    Returns:
    the found Fields
  - presentSinkFields
```
public void presentSinkFields(FlowProcess<? extends Config> flowProcess,
                     Fields fields)
```
  - resolveIncomingOperationArgumentFields
```
public Fields resolveIncomingOperationArgumentFields(Scope incomingScope)
```
    Description copied from interface: ScopedElement
    
    Method resolveIncomingOperationArgumentFields returns the Fields outgoing from the previous FlowElement that are consumable by this FlowElement when preparing Operation arguments.
    
    Specified by:
    
    resolveIncomingOperationArgumentFields in interface ScopedElement
    
    Parameters:
    incomingScope - of type Scope
    
    Returns:
    Fields
  - resolveIncomingOperationPassThroughFields
```
public Fields resolveIncomingOperationPassThroughFields(Scope incomingScope)
```
    Description copied from interface: ScopedElement
    
    Method resolveIncomingOperationPassThroughFields returns the Fields outgoing from the previous FlowElement that are consumable by this FlowElement when preparing the Pipe outgoing tuple.
    
    Specified by:
    
    resolveIncomingOperationPassThroughFields in interface ScopedElement
    
    Parameters:
    incomingScope - of type Scope
    
    Returns:
    Fields
  - getFullIdentifier
```
public String getFullIdentifier(FlowProcess<? extends Config> flowProcess)
```
    Method getFullIdentifier returns a fully qualified resource identifier.
    
    Parameters:
    flowProcess - of type FlowProcess
    
    Returns:
    String
  - getFullIdentifier
```
public String getFullIdentifier(Config conf)
```
    Method getFullIdentifier returns a fully qualified resource identifier.
    
    Parameters:
    conf - of type Config
    
    Returns:
    String
  - createResource
```
public boolean createResource(FlowProcess<? extends Config> flowProcess)
                       throws IOException
```
    Method createResource creates the underlying resource.
    
    Parameters:
    flowProcess - of type FlowProcess
    
    Returns:
    boolean
    
    Throws:
    
    IOException - when there is an error making directories
  - createResource
```
public abstract boolean createResource(Config conf)
                                throws IOException
```
    Method createResource creates the underlying resource.
    
    Parameters:
    conf - of type Config
    
    Returns:
    boolean
    
    Throws:
    
    IOException - when there is an error making directories
  - deleteResource
```
public boolean deleteResource(FlowProcess<? extends Config> flowProcess)
                       throws IOException
```
    Method deleteResource deletes the resource represented by this instance.
    
    Parameters:
    flowProcess - of type FlowProcess
    
    Returns:
    boolean
    
    Throws:
    
    IOException - when the resource cannot be deleted
  - deleteResource
```
public abstract boolean deleteResource(Config conf)
                                throws IOException
```
    Method deleteResource deletes the resource represented by this instance.
    
    Parameters:
    conf - of type Config
    
    Returns:
    boolean
    
    Throws:
    
    IOException - when the resource cannot be deleted
  - prepareResourceForRead
```
public boolean prepareResourceForRead(Config conf)
                               throws IOException
```
    Method prepareResourceForRead allows the underlying resource to be notified when reading will begin.
    This method will be called client side so that any remote or external resources can be initialized.
    If this method returns false, an exception will be thrown halting the current Flow.
    In most cases, resource initialization should happen in the openForRead(FlowProcess, Object) method.
    This allows for initialization of cluster side resources, like a JDBC driver used to read data from a database, that cannot be passed client to cluster.
    
    Parameters:
    conf - of type Config
    
    Returns:
    returns true if successful
    
    Throws:
    
    IOException
  - prepareResourceForWrite
```
public boolean prepareResourceForWrite(Config conf)
                                throws IOException
```
    Method prepareResourceForWrite allows the underlying resource to be notified when writing will begin.
    This method will be called once client side so that any remote or external resources can be initialized.
    If this method returns false, an exception will be thrown halting the current Flow.
    In most cases, resource initialization should happen in the openForWrite(FlowProcess, Object) method.
    This allows for initialization of cluster side resources, like a JDBC driver used to write data to a database, that cannot be passed client to cluster.
    In the above JDBC example, overriding this method will allow for testing for the existence of and/or creating a remote table used by all individual cluster side tasks.
    
    Parameters:
    conf - of type Config
    
    Returns:
    returns true if successful
    
    Throws:
    
    IOException
  - commitResource
```
public boolean commitResource(Config conf)
                       throws IOException
```
    Method commitResource allows the underlying resource to be notified when all write processing is successful so that any additional cleanup or processing may be completed.
    See rollbackResource(Object) to handle cleanup in the face of failures.
    This method is invoked once client side and not in the cluster, if any.
    If other sink Tap instance in a given Flow fail on commitResource after called on this instance, rollbackResource will not be called.
    
    Parameters:
    conf - of type Config
    
    Returns:
    returns true if successful
    
    Throws:
    
    IOException
  - rollbackResource
```
public boolean rollbackResource(Config conf)
                         throws IOException
```
    Method rollbackResource allows the underlying resource to be notified when any write processing has failed or was stopped so that any cleanup may be started.
    See commitResource(Object) to handle cleanup when the write has successfully completed.
    This method is invoked once client side and not in the cluster, if any.
    
    Parameters:
    conf - of type Config
    
    Returns:
    returns true if successful
    
    Throws:
    
    IOException
  - resourceExists
```
public boolean resourceExists(FlowProcess<? extends Config> flowProcess)
                       throws IOException
```
    Method resourceExists returns true if the path represented by this instance exists.
    
    Parameters:
    flowProcess - of type FlowProcess
    
    Returns:
    true if the underlying resource already exists
    
    Throws:
    
    IOException - when the status cannot be determined
  - resourceExists
```
public abstract boolean resourceExists(Config conf)
                                throws IOException
```
    Method resourceExists returns true if the path represented by this instance exists.
    
    Parameters:
    conf - of type Config
    
    Returns:
    true if the underlying resource already exists
    
    Throws:
    
    IOException - when the status cannot be determined
  - getModifiedTime
```
public long getModifiedTime(FlowProcess<? extends Config> flowProcess)
                     throws IOException
```
    Method getModifiedTime returns the date this resource was last modified.
    
    Parameters:
    flowProcess - of type FlowProcess
    
    Returns:
    The date this resource was last modified.
    
    Throws:
    
    IOException
  - getModifiedTime
```
public abstract long getModifiedTime(Config conf)
                              throws IOException
```
    Method getModifiedTime returns the date this resource was last modified.
    
    Parameters:
    conf - of type Config
    
    Returns:
    The date this resource was last modified.
    
    Throws:
    
    IOException
  - getSinkMode
```
public SinkMode getSinkMode()
```
    Method getSinkMode returns the SinkMode }of this Tap object.
    
    Returns:
    the sinkMode (type SinkMode) of this Tap object.
  - isKeep
```
public boolean isKeep()
```
    Method isKeep indicates whether the resource represented by this instance should be kept if it already exists when the Flow is started.
    
    Returns:
    boolean
  - isReplace
```
public boolean isReplace()
```
    Method isReplace indicates whether the resource represented by this instance should be deleted if it already exists when the Flow is started.
    
    Returns:
    boolean
  - isUpdate
```
public boolean isUpdate()
```
    Method isUpdate indicates whether the resource represented by this instance should be updated if it already exists. Otherwise a new resource will be created, via createResource(Object), when the Flow is started.
    
    Returns:
    boolean
  - isSink
```
public boolean isSink()
```
    Method isSink returns true if this Tap instance can be used as a sink.
    
    Returns:
    boolean
  - isSource
```
public boolean isSource()
```
    Method isSource returns true if this Tap instance can be used as a source.
    
    Returns:
    boolean
  - isTemporary
```
public boolean isTemporary()
```
    Method isTemporary returns true if this Tap is temporary (used for intermediate results).
    
    Returns:
    the temporary (type boolean) of this Tap object.
  - getConfigDef
```
public ConfigDef getConfigDef()
```
    Returns a ConfigDef instance that allows for local properties to be set and made available via a resulting FlowProcess instance when the tap is invoked.
    Any properties set on the configDef will not show up in any Flow or FlowStep process level configuration, but will override any of those values as seen by the current Tap instance method call where a FlowProcess is provided except for the sourceConfInit(cascading.flow.FlowProcess, Object) and sinkConfInit(cascading.flow.FlowProcess, Object) methods.
    That is, the *confInit methods are called before any ConfigDef is applied, so any values placed into a ConfigDef instance will not be visible to them.
    
    Specified by:
    
    getConfigDef in interface ScopedElement
    
    Returns:
    an instance of ConfigDef
  - hasConfigDef
```
public boolean hasConfigDef()
```
    Returns true if there are properties in the configDef instance.
    
    Specified by:
    
    hasConfigDef in interface ScopedElement
    
    Returns:
    true if there are configDef properties
  - getNodeConfigDef
```
public ConfigDef getNodeConfigDef()
```
    Returns a ConfigDef instance that allows for process level properties to be set and made available via a resulting FlowProcess instance when the tap is invoked.
    Any properties set on the nodeConfigDef will not show up in any Flow configuration, but will show up in the current process FlowNode (in Apache Tez the Vertex configuration). Any value set in the nodeConfigDef will be overridden by the pipe local #getConfigDef instance.
    Use this method to tweak properties in the process node this tap instance is planned into.
    
    Specified by:
    
    getNodeConfigDef in interface ScopedElement
    
    Returns:
    an instance of ConfigDef
  - hasNodeConfigDef
```
public boolean hasNodeConfigDef()
```
    Returns true if there are properties in the nodeConfigDef instance.
    
    Specified by:
    
    hasNodeConfigDef in interface ScopedElement
    
    Returns:
    true if there are nodeConfigDef properties
  - getStepConfigDef
```
public ConfigDef getStepConfigDef()
```
    Returns a ConfigDef instance that allows for process level properties to be set and made available via a resulting FlowProcess instance when the tap is invoked.
    Any properties set on the stepConfigDef will not show up in any Flow configuration, but will show up in the current process FlowStep (in Hadoop the MapReduce jobconf). Any value set in the stepConfigDef will be overridden by the tap local #getConfigDef instance.
    Use this method to tweak properties in the process step this tap instance is planned into.
    Note the *confInit methods are called before any ConfigDef is applied, so any values placed into a ConfigDef instance will not be visible to them.
    
    Specified by:
    
    getStepConfigDef in interface ScopedElement
    
    Returns:
    an instance of ConfigDef
  - hasStepConfigDef
```
public boolean hasStepConfigDef()
```
    Returns true if there are properties in the stepConfigDef instance.
    
    Specified by:
    
    hasStepConfigDef in interface ScopedElement
    
    Returns:
    true if there are stepConfigDef properties
  - equals
```
public boolean equals(Object object)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object

Class Tap<Config,Input,Output>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Tap

Tap

Tap

Method Detail

taps

id

setScheme

getScheme

getTrace

flowConfInit

sourceConfInit

sinkConfInit

getIdentifier

getSourceFields

getSinkFields

openForRead

openForRead

openForWrite

openForWrite

outgoingScopeFor

retrieveSourceFields

presentSourceFields

retrieveSinkFields

presentSinkFields

resolveIncomingOperationArgumentFields

resolveIncomingOperationPassThroughFields

getFullIdentifier

getFullIdentifier

createResource

createResource

deleteResource

deleteResource

prepareResourceForRead

prepareResourceForWrite

commitResource

rollbackResource

resourceExists

resourceExists

getModifiedTime

getModifiedTime

getSinkMode

isKeep

isReplace

isUpdate

isSink

isSource

isTemporary

getConfigDef

hasConfigDef

getNodeConfigDef

hasNodeConfigDef

getStepConfigDef

hasStepConfigDef

equals

hashCode

toString