cascading.operation.filter

Class Limit

java.lang.Object

cascading.operation.BaseOperation<Limit.Context>

cascading.operation.filter.Limit

All Implemented Interfaces:

DeclaresResults, Filter<Limit.Context>, Operation<Limit.Context>, Traceable, java.io.Serializable

public class Limit
extends BaseOperation<Limit.Context>
implements Filter<Limit.Context>

Class Limit is a Filter that will limit the number of Tuple instances that it will allow to pass.
Note that the limit value is roughly a suggestion. It attempts to divide the limit number by the number of concurrent tasks, but knowing the number of tasks isn't easily available from configuration information provided to individual tasks. Further, the number of records/lines available to a task may be less than the limit amount.
More consistent results will be received from using Sample.

See Also:

Sample, Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Limit.Context

Field Summary

Fields inherited from class cascading.operation.BaseOperation

fieldDeclaration, numArgs, trace

Fields inherited from interface cascading.operation.Operation

ANY

Constructor Summary

Constructors

Constructor and Description
Limit(long limit) Creates a new Limit class that only allows limit number of Tuple instances to pass.

Method Summary

Modifier and Type	Method and Description
boolean	equals(java.lang.Object object)
long	getLimit()
int	hashCode()
boolean	isRemove(FlowProcess flowProcess, FilterCall<Limit.Context> filterCall) Method isRemove returns true if input should be removed from the tuple stream.
void	prepare(FlowProcess flowProcess, OperationCall<Limit.Context> operationCall) Method prepare does nothing, and may safely be overridden.

Methods inherited from class cascading.operation.BaseOperation

cleanup, flush, getFieldDeclaration, getNumArgs, getTrace, isSafe, printOperationInternal, toString, toStringInternal

Methods inherited from class java.lang.Object

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

Methods inherited from interface cascading.operation.Operation

cleanup, flush, getFieldDeclaration, getNumArgs, isSafe

Constructor Detail

Limit

@ConstructorProperties(value="limit")
public Limit(long limit)

Creates a new Limit class that only allows limit number of Tuple instances to pass.

Parameters:

limit - the number of tuples to let pass

Method Detail

getLimit

public long getLimit()

prepare

public void prepare(FlowProcess flowProcess,
                    OperationCall<Limit.Context> operationCall)

Description copied from class: BaseOperation

Method prepare does nothing, and may safely be overridden.

Specified by:

prepare in interface Operation<Limit.Context>

Overrides:

prepare in class BaseOperation<Limit.Context>

isRemove

public boolean isRemove(FlowProcess flowProcess,
                        FilterCall<Limit.Context> filterCall)

Description copied from interface: Filter

Method isRemove returns true if input should be removed from the tuple stream.

Specified by:

isRemove in interface Filter<Limit.Context>

Parameters:

flowProcess - of type FlowProcess

filterCall - of type FilterCall

Returns:

boolean

equals

public boolean equals(java.lang.Object object)

Overrides:

equals in class BaseOperation<Limit.Context>

hashCode

public int hashCode()

Overrides:

hashCode in class BaseOperation<Limit.Context>