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

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

All Implemented Interfaces:

SQLMethod

public class ListGetMethod
extends AbstractSQLMethod

Method for evaluating {listExpr}.get(idxExpr). Returns an ObjectExpression representing the element

Field Summary

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

clr, exprFactory, LOCALISER, stmt

Constructor Summary

ListGetMethod()

Method Summary

protected SQLExpression	getAsInnerJoin(CollectionExpression listExpr, SQLExpression idxExpr) Implementation of List.get() using an inner join to the table representing the list, adding a condition on the index and returning the element.
protected SQLExpression	getAsSubquery(CollectionExpression listExpr, SQLExpression idxExpr) Implementation of Collection.get() using a subquery on the table representing the collection, adding a condition on the index and returning the element.
SQLExpression	getExpression(SQLExpression expr, List args) Return the expression for this SQL function.

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

ListGetMethod

public ListGetMethod()

Method Detail

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

getAsSubquery

protected SQLExpression getAsSubquery(CollectionExpression listExpr,
                                      SQLExpression idxExpr)

Implementation of Collection.get() using a subquery on the table representing the collection, adding a condition on the index and returning the element.

Parameters:

listExpr - The list expression

idxExpr - The index expression

Returns:

The element expression

getAsInnerJoin

protected SQLExpression getAsInnerJoin(CollectionExpression listExpr,
                                       SQLExpression idxExpr)

Implementation of List.get() using an inner join to the table representing the list, adding a condition on the index and returning the element.

Parameters:

listExpr - The list expression

idxExpr - The index expression

Returns:

The element expression