cascading.operation

Class ConcreteCall<C>

java.lang.Object

cascading.operation.ConcreteCall<C>

All Implemented Interfaces:

AggregatorCall<C>, BufferCall<C>, FilterCall<C>, FunctionCall<C>, GroupAssertionCall<C>, OperationCall<C>, ValueAssertionCall<C>

public class ConcreteCall<C>
extends java.lang.Object
implements FunctionCall<C>, FilterCall<C>, AggregatorCall<C>, BufferCall<C>, ValueAssertionCall<C>, GroupAssertionCall<C>

Class OperationCall is the common base class for FunctionCall, FilterCall, AggregatorCall, ValueAssertionCall, and GroupAssertionCall.

Constructor Summary

Constructors

Constructor and Description
ConcreteCall() Constructor OperationCall creates a new OperationCall instance.
ConcreteCall(ConcreteCall<C> concreteCall)
ConcreteCall(Fields argumentFields) Constructor ConcreteCall creates a new ConcreteCall instance.
ConcreteCall(Fields argumentFields, Fields declaredFields) Constructor ConcreteCall creates a new ConcreteCall instance.
ConcreteCall(TupleEntry arguments, TupleEntryCollector outputCollector) Constructor OperationCall creates a new OperationCall instance.

Method Summary

Modifier and Type	Method and Description
Fields	getArgumentFields() Returns the Fields of the expected arguments TupleEntry.
TupleEntry	getArguments() Returns TupleEntry of argument values.
java.util.Iterator<TupleEntry>	getArgumentsIterator() Returns an Iterator of TupleEntry instances representing the arguments for the called Buffer.operate(cascading.flow.FlowProcess, BufferCall) method.
C	getContext() Returns the user set context object, C.
Fields	getDeclaredFields() Return the resolved Fields declared by the current Operation.
TupleEntry	getGroup() Returns the current grouping TupleEntry.
JoinerClosure	getJoinerClosure() Returns the current instance of a JoinerClosure, if any.
TupleEntryCollector	getOutputCollector() Returns the TupleEntryCollector used to emit result values.
boolean	isRetainValues() Returns true if non-grouping fields will not be nulled after the argumentsIterator is completed.
void	setArgumentFields(Fields argumentFields)
void	setArguments(TupleEntry arguments)
void	setArgumentsIterator(java.util.Iterator<TupleEntry> argumentsIterator)
void	setContext(C context) Sets the user defined 'context' object.
void	setGroup(TupleEntry group)
void	setJoinerClosure(JoinerClosure joinerClosure)
void	setOutputCollector(TupleEntryCollector outputCollector)
void	setRetainValues(boolean retainValues) Set to false if at the end of all values iterated over in the argumentsIterator, the last seen argument tuple values should not be nulled out.

Methods inherited from class java.lang.Object

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

Constructor Detail

ConcreteCall

public ConcreteCall()

Constructor OperationCall creates a new OperationCall instance.

ConcreteCall

public ConcreteCall(Fields argumentFields)

Constructor ConcreteCall creates a new ConcreteCall instance.

Parameters:

argumentFields - of type Fields

ConcreteCall

public ConcreteCall(Fields argumentFields,
                    Fields declaredFields)

Constructor ConcreteCall creates a new ConcreteCall instance.

Parameters:

argumentFields - of type Fields

declaredFields - of type Fields

ConcreteCall

public ConcreteCall(TupleEntry arguments,
                    TupleEntryCollector outputCollector)

Constructor OperationCall creates a new OperationCall instance.

Parameters:

arguments - of type TupleEntry

outputCollector - of type TupleCollector

ConcreteCall

public ConcreteCall(ConcreteCall<C> concreteCall)

Method Detail

getContext

public C getContext()

Description copied from interface: OperationCall

Returns the user set context object, C.

Specified by:

getContext in interface OperationCall<C>

Returns:

user defined object

See Also:

OperationCall.getContext()

setContext

public void setContext(C context)

Description copied from interface: OperationCall

Sets the user defined 'context' object.

Specified by:

setContext in interface OperationCall<C>

Parameters:

context - user defined object

getGroup

public TupleEntry getGroup()

Description copied from interface: AggregatorCall

Returns the current grouping TupleEntry.

Specified by:

getGroup in interface AggregatorCall<C>

Specified by:

getGroup in interface BufferCall<C>

Specified by:

getGroup in interface GroupAssertionCall<C>

Returns:

TupleEntry

See Also:

AggregatorCall.getGroup()

setGroup

public void setGroup(TupleEntry group)

getArgumentFields

public Fields getArgumentFields()

Description copied from interface: OperationCall

Returns the Fields of the expected arguments TupleEntry.

Specified by:

getArgumentFields in interface OperationCall<C>

Returns:

the argumentFields (type Fields) of this OperationCall object.

setArgumentFields

public void setArgumentFields(Fields argumentFields)

getArgumentsIterator

public java.util.Iterator<TupleEntry> getArgumentsIterator()

Description copied from interface: BufferCall

Returns an Iterator of TupleEntry instances representing the arguments for the called Buffer.operate(cascading.flow.FlowProcess, BufferCall) method.

The return value may be null if the previous CoGroup declares BufferJoin as the Joiner.

See BufferCall.getJoinerClosure().

Note that the returned TupleEntry should not be cached (stored in a Collection), nor should the underlying Tuple instance. Where possible Cascading will re-use both TupleEntry and Tuple instances.

To get a safe copy that can be cached, use TupleEntry.getTupleCopy().

Specified by:

getArgumentsIterator in interface BufferCall<C>

Returns:

Iterator

See Also:

BufferCall.getArgumentsIterator()

setArgumentsIterator

public void setArgumentsIterator(java.util.Iterator<TupleEntry> argumentsIterator)

getArguments

public TupleEntry getArguments()

Description copied from interface: FunctionCall

Returns TupleEntry of argument values.

Note that the returned TupleEntry should not be cached (stored in a Collection), nor should the underlying Tuple instance. Where possible Cascading will re-use both TupleEntry and Tuple instances.

To get a safe copy that can be cached, use TupleEntry.getTupleCopy().

Specified by:

getArguments in interface AggregatorCall<C>

Specified by:

getArguments in interface FilterCall<C>

Specified by:

getArguments in interface FunctionCall<C>

Specified by:

getArguments in interface GroupAssertionCall<C>

Specified by:

getArguments in interface ValueAssertionCall<C>

Returns:

TupleEntry

See Also:

FunctionCall.getArguments()

setArguments

public void setArguments(TupleEntry arguments)

getDeclaredFields

public Fields getDeclaredFields()

Description copied from interface: FunctionCall

Return the resolved Fields declared by the current Operation.

Specified by:

getDeclaredFields in interface AggregatorCall<C>

Specified by:

getDeclaredFields in interface BufferCall<C>

Specified by:

getDeclaredFields in interface FunctionCall<C>

Specified by:

getDeclaredFields in interface OperationCall<C>

Returns:

Fields

getOutputCollector

public TupleEntryCollector getOutputCollector()

Description copied from interface: FunctionCall

Returns the TupleEntryCollector used to emit result values.

Specified by:

getOutputCollector in interface AggregatorCall<C>

Specified by:

getOutputCollector in interface BufferCall<C>

Specified by:

getOutputCollector in interface FunctionCall<C>

Returns:

TupleCollector

See Also:

FunctionCall.getOutputCollector()

setOutputCollector

public void setOutputCollector(TupleEntryCollector outputCollector)

setRetainValues

public void setRetainValues(boolean retainValues)

Description copied from interface: BufferCall

Set to false if at the end of all values iterated over in the argumentsIterator, the last seen argument tuple values should not be nulled out.

By default, if a result is emitted from the Buffer before and after the argumentsIterator is started or completed, the last seen non-grouping values are null. When false, the values are not nulled after completion.

The default is true.

Specified by:

setRetainValues in interface BufferCall<C>

Parameters:

retainValues - of type boolean

isRetainValues

public boolean isRetainValues()

Description copied from interface: BufferCall

Returns true if non-grouping fields will not be nulled after the argumentsIterator is completed.

Specified by:

isRetainValues in interface BufferCall<C>

Returns:

true

setJoinerClosure

public void setJoinerClosure(JoinerClosure joinerClosure)

getJoinerClosure

public JoinerClosure getJoinerClosure()

Description copied from interface: BufferCall

Returns the current instance of a JoinerClosure, if any. This allows a Buffer to implement its own join strategy against the incoming tuple streams.

The return value is always null unless the declared fields on the CoGroup are Fields.NONE.

Note this method is provided as a means to bypass some of the Cascading internals in order to improve the implementations (performance or maintainability) behind some algorithms.

Consider it only if you are an advanced user. Or more robustly, consider implementing a custom Joiner.

Specified by:

getJoinerClosure in interface BufferCall<C>

Returns:

JoinerClosure