cascading.operation
Class Identity

java.lang.Object
  cascading.operation.BaseOperation
      cascading.operation.Identity

All Implemented Interfaces:

Function, Operation, Serializable

public class Identity
extends BaseOperation
implements Function

The Identity function simply passes incoming arguments back out again. Optionally argument fields can be renamed, and/or coerced into specfic types.

See Also:

Serialized Form

Field Summary

Fields inherited from class cascading.operation.BaseOperation

fieldDeclaration, numArgs, trace

Fields inherited from interface cascading.operation.Operation

ANY

Constructor Summary

Identity()
Constructor Identity creates a new Identity instance that will pass the argument values to its output.

Identity(Class... types)
Constructor Identity creates a new Identity instance that will coerce the values to the give types.

Identity(Fields fieldDeclaration)
Constructor Identity creates a new Identity instance that will rename the argument fields to the given fieldDeclaration.

Identity(Fields fieldDeclaration, Class... types)
Constructor Identity creates a new Identity instance that will rename the argument fields to the given fieldDeclaration, and coerce the values to the give types.

Method Summary

void	operate(FlowProcess flowProcess, FunctionCall functionCall) Method operate provides the implementation of this Function.

Methods inherited from class cascading.operation.BaseOperation

cleanup, getFieldDeclaration, getNumArgs, getTrace, prepare, printOperationInternal, toString, toStringInternal

Methods inherited from class java.lang.Object

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

Methods inherited from interface cascading.operation.Operation

cleanup, getFieldDeclaration, getNumArgs, prepare

Constructor Detail

Identity

public Identity()

Constructor Identity creates a new Identity instance that will pass the argument values to its output. Use this constructor for a simple copy Pipe.

Identity

public Identity(Class... types)

Constructor Identity creates a new Identity instance that will coerce the values to the give types.

Parameters:

types - of type Class...

Identity

public Identity(Fields fieldDeclaration)

Constructor Identity creates a new Identity instance that will rename the argument fields to the given fieldDeclaration.

Parameters:

fieldDeclaration - of type Fields

Identity

public Identity(Fields fieldDeclaration,
                Class... types)

Constructor Identity creates a new Identity instance that will rename the argument fields to the given fieldDeclaration, and coerce the values to the give types.

Parameters:

fieldDeclaration - of type Fields

types - of type Class...

Method Detail

operate

public void operate(FlowProcess flowProcess,
                    FunctionCall functionCall)

Description copied from interface: Function

Method operate provides the implementation of this Function.

Specified by:

operate in interface Function

Parameters:

flowProcess - of type FlowProcess

functionCall - of type FunctionCall

See Also:

Function.operate(cascading.flow.FlowProcess, FunctionCall)