org.datanucleus.store.rdbms.sql.method
Class SimpleOrderableAggregateMethod

java.lang.Object
  org.datanucleus.store.rdbms.sql.method.AbstractSQLMethod
      org.datanucleus.store.rdbms.sql.method.SimpleOrderableAggregateMethod

All Implemented Interfaces:

SQLMethod

Direct Known Subclasses:

MaxFunction, MinFunction

public abstract class SimpleOrderableAggregateMethod
extends AbstractSQLMethod

Expression handler to invoke an SQL aggregated function.

• The expression should be null and will return an AggregateXXXExpression

  {functionName}({argExpr})

  when processing a result clause
• If the compilation component is something else then will generate a subquery expression

Field Summary

Fields inherited from class org.datanucleus.store.rdbms.sql.method.AbstractSQLMethod

clr, exprFactory, LOCALISER, stmt

Constructor Summary

SimpleOrderableAggregateMethod()

Method Summary

SQLExpression	getExpression(SQLExpression expr, List args) Return the expression for this SQL function.
protected abstract String	getFunctionName()

Methods inherited from class org.datanucleus.store.rdbms.sql.method.AbstractSQLMethod

getMappingForClass, setStatement

Methods inherited from class java.lang.Object

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

Constructor Detail

SimpleOrderableAggregateMethod

public SimpleOrderableAggregateMethod()

Method Detail

getFunctionName

protected abstract String getFunctionName()

getExpression

public SQLExpression getExpression(SQLExpression expr,
                                   List args)

Description copied from interface: SQLMethod

Return the expression for this SQL function.

Parameters:

expr - The expression that it is invoked on

args - Arguments passed in

Returns:

The SQL expression using the SQL function