Package org.datanucleus.store.rdbms.sql.method

Class AvgFunction

java.lang.Object

org.datanucleus.store.rdbms.sql.method.SimpleNumericAggregateMethod

org.datanucleus.store.rdbms.sql.method.AvgFunction

All Implemented Interfaces:

SQLMethod

Direct Known Subclasses:

AvgWithCastFunction

public class AvgFunction
extends SimpleNumericAggregateMethod

Expression handler to invoke the SQL AVG aggregation function. For use in evaluating AVG({expr}) where the RDBMS supports this function. Returns a NumericExpression "AVG({numericExpr})".

Constructor Summary

Constructors

Constructor	Description
AvgFunction()

Method Summary

Modifier and Type	Method	Description
protected SQLExpression	getAggregateExpression(SQLStatement stmt, List args, JavaTypeMapping m)
protected Class	getClassForMapping()
SQLExpression	getExpression(SQLStatement stmt, SQLExpression expr, List args)	Return the expression for this SQL function.
protected String	getFunctionName()

Methods inherited from class java.lang.Object

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

Constructor Detail

AvgFunction

public AvgFunction()

Method Detail

getFunctionName

protected String getFunctionName()

Specified by:

getFunctionName in class SimpleNumericAggregateMethod

getExpression

public SQLExpression getExpression(SQLStatement stmt,
                                   SQLExpression expr,
                                   List args)

Description copied from interface: SQLMethod

Return the expression for this SQL function.

Specified by:

getExpression in interface SQLMethod

Overrides:

getExpression in class SimpleNumericAggregateMethod

Parameters:

stmt - SQLStatement that this expression is for

expr - The expression that it is invoked on

args - Arguments passed in

Returns:

The SQL expression using the SQL function

getAggregateExpression

protected SQLExpression getAggregateExpression(SQLStatement stmt,
                                               List args,
                                               JavaTypeMapping m)

getClassForMapping

protected Class getClassForMapping()

Specified by:

getClassForMapping in class SimpleNumericAggregateMethod