uk.ac.ed.epcc.safe.accounting

Class ReductionTarget<T>

java.lang.Object

uk.ac.ed.epcc.safe.accounting.ReductionTarget<T>

Type Parameters:

T -

Direct Known Subclasses:

DateReductionTarget, IndexReduction, NumberReductionTarget

public abstract class ReductionTarget<T>
extends java.lang.Object

A ReductionTarget represents a Reduction of a PropExpression over set of records.

Author:

spb

Constructor Summary

Constructors

Constructor and Description
ReductionTarget(java.lang.Class<T> target, Reduction op, PropExpression<? extends T> tag)

Method Summary

Methods

Modifier and Type	Method and Description
abstract T	combine(T a, T b) Combine two partial values.
boolean	equals(java.lang.Object obj)
T	getDefault() value to return if no records combined,
PropExpression<? extends T>	getExpression()
Reduction	getReduction()
java.lang.Class<T>	getTarget()
int	hashCode()
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ReductionTarget

public ReductionTarget(java.lang.Class<T> target,
               Reduction op,
               PropExpression<? extends T> tag)
                throws IllegalReductionException

Throws:

IllegalReductionException

Method Detail

getReduction

public final Reduction getReduction()

getExpression

public PropExpression<? extends T> getExpression()

getTarget

public final java.lang.Class<T> getTarget()

combine

public abstract T combine(T a,
        T b)

Combine two partial values. The default value must be a legal input

Parameters:

a -

b -

Returns:

combined result

getDefault

public T getDefault()

value to return if no records combined,

Returns:

default value

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object