cascading.operation
Interface GroupAssertion<C>
- All Superinterfaces:
- Assertion<C>, Operation<C>, PlannedOperation<C>
- All Known Implementing Classes:
- AssertGroupBase, AssertGroupSizeEquals, AssertGroupSizeLessThan, AssertGroupSizeMoreThan
public interface GroupAssertion<C>
- extends Assertion<C>
Class GroupAssertion is a kind of Assertion
used with the Every
pipe Operator.
Implementers should also extend BaseOperation
.
- See Also:
Aggregator
Fields inherited from interface cascading.operation.Operation |
ANY |
start
void start(FlowProcess flowProcess,
GroupAssertionCall<C> assertionCall)
- Method start initializes the aggregation procedure and is called for every unique grouping.
The AggregatorCall context should be initialized here if necessary.
The first time this method is called for a given 'process', the AggregatorCall context will be null. This method should
set a new instance of the user defined context object. When the AggregatorCall context is not null, it is up to
the developer to create a new instance, or 'recycle' the given instance. If recycled, it must be re-initialized to
remove any previous state/values.
For example, if a Map is used to hold the intermediate data for each subsequent
aggregate(cascading.flow.FlowProcess, GroupAssertionCall)
call,
new HashMap() should be set on the AggregatorCall instance when OperationCall.getContext()
is null.
On the next grouping, start() will be called again, but this time with the old Map instance. In this case,
map.clear() should be invoked before returning.
- Parameters:
flowProcess
- of type FlowProcessassertionCall
- of type GroupAssertionCall
aggregate
void aggregate(FlowProcess flowProcess,
GroupAssertionCall<C> assertionCall)
- Method aggregate is called for each
TupleEntry
value in the current grouping.
- Parameters:
flowProcess
- of type FlowProcessassertionCall
- of type GroupAssertionCall
doAssert
void doAssert(FlowProcess flowProcess,
GroupAssertionCall<C> assertionCall)
- Method doAssert performs the assertion.
- Parameters:
flowProcess
- of type FlowProcessassertionCall
- of type GroupAssertionCall
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