Class MaxMinAggregateDefinition
- java.lang.Object
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- org.apache.derby.impl.sql.compile.MaxMinAggregateDefinition
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- All Implemented Interfaces:
AggregateDefinition
class MaxMinAggregateDefinition extends java.lang.Object implements AggregateDefinition
Defintion for the MAX()/MIN() aggregates.
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Field Summary
Fields Modifier and Type Field Description private boolean
isMax
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Constructor Summary
Constructors Constructor Description MaxMinAggregateDefinition()
Niladic constructor.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description DataTypeDescriptor
getAggregator(DataTypeDescriptor inputType, java.lang.StringBuffer aggregatorClass)
Determines the result datatype.(package private) boolean
isMax()
Return if the aggregator class is for min/max.(package private) void
setMaxOrMin(boolean isMax)
This is set by the parser.
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Method Detail
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getAggregator
public final DataTypeDescriptor getAggregator(DataTypeDescriptor inputType, java.lang.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:
TypeDescriptor
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setMaxOrMin
final void setMaxOrMin(boolean isMax)
This is set by the parser.
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isMax
final boolean isMax()
Return if the aggregator class is for min/max.- Returns:
- boolean true/false
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