Class MaxMinAggregateDefinition
java.lang.Object
org.apache.derby.impl.sql.compile.MaxMinAggregateDefinition
- All Implemented Interfaces:
AggregateDefinition
Defintion for the MAX()/MIN() aggregates.
-
Field Summary
Fields -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionfinal DataTypeDescriptor
getAggregator
(DataTypeDescriptor inputType, StringBuffer aggregatorClass) Determines the result datatype.(package private) final boolean
isMax()
Return if the aggregator class is for min/max.(package private) final void
setMaxOrMin
(boolean isMax) This is set by the parser.
-
Field Details
-
isMax
private boolean isMax
-
-
Constructor Details
-
MaxMinAggregateDefinition
public MaxMinAggregateDefinition()Niladic constructor. Does nothing. For ease Of use, only.
-
-
Method Details
-
getAggregator
public final DataTypeDescriptor getAggregator(DataTypeDescriptor inputType, StringBuffer aggregatorClass) Determines the result datatype. Accept NumberDataValues only.Note: In the future you should be able to do a sum user data types. One option would be to run sum on anything that implements divide().
- Specified by:
getAggregator
in interfaceAggregateDefinition
- Parameters:
inputType
- the input type, either a user type or a java.lang objectaggregatorClass
- output parameter, filled in with the class name that implements com.ibm.db2j.aggregates.Aggregator- Returns:
- the output Class (null if cannot operate on value expression of this type.
- See Also:
-
setMaxOrMin
final void setMaxOrMin(boolean isMax) This is set by the parser. -
isMax
final boolean isMax()Return if the aggregator class is for min/max.- Returns:
- boolean true/false
-