org.apache.derby.impl.sql.execute
Class SystemAggregator
java.lang.Object
org.apache.derby.impl.sql.execute.SystemAggregator
- All Implemented Interfaces:
- java.io.Externalizable, java.io.Serializable, Formatable, TypedFormat, ExecAggregator
- Direct Known Subclasses:
- CountAggregator, OrderableAggregator
abstract class SystemAggregator
- extends java.lang.Object
- implements ExecAggregator
Abstract aggregator that is extended by all internal
(system) aggregators.
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
eliminatedNulls
private boolean eliminatedNulls
SystemAggregator
SystemAggregator()
didEliminateNulls
public boolean didEliminateNulls()
- Description copied from interface:
ExecAggregator
- Return true if the aggregation eliminated at least one
null from the input data set.
- Specified by:
didEliminateNulls
in interface ExecAggregator
accumulate
public void accumulate(DataValueDescriptor addend,
java.lang.Object ga)
throws StandardException
- Description copied from interface:
ExecAggregator
- Iteratively accumulates the addend into the aggregator.
Called on each member of the set of values that is being
aggregated.
- Specified by:
accumulate
in interface ExecAggregator
- Parameters:
addend
- the DataValueDescriptor addend (current input to
the aggregation)ga
- a result set getter
- Throws:
StandardException
- on error
accumulate
protected abstract void accumulate(DataValueDescriptor addend)
throws StandardException
- Throws:
StandardException
writeExternal
public void writeExternal(java.io.ObjectOutput out)
throws java.io.IOException
- Specified by:
writeExternal
in interface java.io.Externalizable
- Throws:
java.io.IOException
readExternal
public void readExternal(java.io.ObjectInput in)
throws java.io.IOException,
java.lang.ClassNotFoundException
- Specified by:
readExternal
in interface java.io.Externalizable
- Throws:
java.io.IOException
java.lang.ClassNotFoundException
toString
public java.lang.String toString()
- Overrides:
toString
in class java.lang.Object
Apache Derby V10.6 Internals - Copyright © 2004,2007 The Apache Software Foundation. All Rights Reserved.