com.splicemachine.db.impl.sql.compile

Class RowNumberFunctionDefinition

java.lang.Object

com.splicemachine.db.impl.sql.compile.RowNumberFunctionDefinition

All Implemented Interfaces:

AggregateDefinition

public class RowNumberFunctionDefinition
extends java.lang.Object
implements AggregateDefinition

Nested Class Summary

Nested classes/interfaces inherited from interface com.splicemachine.db.iapi.sql.compile.AggregateDefinition

AggregateDefinition.FunctionType

Constructor Summary

Constructors

Constructor and Description
RowNumberFunctionDefinition()

Method Summary

Modifier and Type	Method and Description
DataTypeDescriptor	getAggregator(DataTypeDescriptor inputType, java.lang.StringBuffer aggregatorClassName) Get the aggregator that performs the aggregation on the input datatype at execution time.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.splicemachine.db.iapi.sql.compile.AggregateDefinition

fromString

Constructor Detail

RowNumberFunctionDefinition

public RowNumberFunctionDefinition()

Method Detail

getAggregator

public DataTypeDescriptor getAggregator(DataTypeDescriptor inputType,
                                        java.lang.StringBuffer aggregatorClassName)
                                 throws StandardException

Description copied from interface: AggregateDefinition

Get the aggregator that performs the aggregation on the input datatype at execution time. If the input type can be handled, return a type descriptor with the resultant type information and fill in the string buffer with the name of the class that is used to perform the aggregation over the input type. If the aggregate cannot be performed on this type, then a null should be returned.

The aggregator class must implement a zero argument constructor. The aggregator class can be the same class as the AggregateDefinition if it implements both interfaces.

The result datatype may be the same as the input datatype or a different datatype. To create your own type descriptor to return to this method, see com.ibm.db2j.types.TypeFactory.

Specified by:

getAggregator in interface AggregateDefinition

Parameters:

inputType - the input type descriptor

aggregatorClassName - output parameter, filled in with the class name that implements com.ibm.db2j.aggregates.Aggregator

Returns:

the output type descriptor (which may or may not be the same as the input type -- it is ok to simply return the input type). Null is returned if the aggregate cannot process the input type. Note that the output type may be a type that maps directly to a standard SQL (e.g. java.lang.Integer) or any other java type (e.g. java.sql.ResultSet, java.util.Vector, java.util.TimeZone or whatever). To construct a type descriptor see com.ibm.db2j.types.TypeFactory.

Throws:

StandardException

See Also:

TypeDescriptor