org.datanucleus.store.rdbms.sql.method

Class ListGetMethod

java.lang.Object

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

All Implemented Interfaces:

SQLMethod

public class ListGetMethod
extends Object
implements SQLMethod

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

Constructor Summary

Constructors

Constructor and Description
ListGetMethod()

Method Summary

Modifier and Type	Method and Description
protected SQLExpression	getAsInnerJoin(SQLStatement stmt, 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(SQLStatement stmt, 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(SQLStatement stmt, SQLExpression expr, List<SQLExpression> args) Return the expression for this SQL function.

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(SQLStatement stmt,
                                   SQLExpression expr,
                                   List<SQLExpression> args)

Description copied from interface: SQLMethod

Return the expression for this SQL function.

Specified by:

getExpression in interface SQLMethod

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

getAsSubquery

protected SQLExpression getAsSubquery(SQLStatement stmt,
                                      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:

stmt - SQLStatement

listExpr - The list expression

idxExpr - The index expression

Returns:

The element expression

getAsInnerJoin

protected SQLExpression getAsInnerJoin(SQLStatement stmt,
                                       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:

stmt - SQLStatement

listExpr - The list expression

idxExpr - The index expression

Returns:

The element expression