org.datanucleus.store.rdbms.sql.method

Class MapGetMethod

java.lang.Object

org.datanucleus.store.rdbms.sql.method.MapGetMethod

All Implemented Interfaces:

SQLMethod

public class MapGetMethod
extends Object
implements SQLMethod

Method for evaluating {mapExpr}.get(keyExpr). Returns an ObjectExpression representing the value

Constructor Summary

Constructors

Constructor and Description
MapGetMethod()

Method Summary

Modifier and Type	Method and Description
protected SQLExpression	getAsInnerJoin(SQLStatement stmt, MapExpression mapExpr, SQLExpression keyValExpr) Implementation of Map.get() using an inner join to the table representing the map, adding a condition on the key and returning the value.
protected SQLExpression	getAsSubquery(SQLStatement stmt, MapExpression mapExpr, SQLExpression keyValExpr) Implementation of Map.get() using a subquery on the table representing the map, adding a condition on the key and returning the value.
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

MapGetMethod

public MapGetMethod()

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,
                                      MapExpression mapExpr,
                                      SQLExpression keyValExpr)

Implementation of Map.get() using a subquery on the table representing the map, adding a condition on the key and returning the value.

Parameters:

stmt - SQLStatement

mapExpr - The map expression

keyValExpr - The key value expression

Returns:

The value expression

getAsInnerJoin

protected SQLExpression getAsInnerJoin(SQLStatement stmt,
                                       MapExpression mapExpr,
                                       SQLExpression keyValExpr)

Implementation of Map.get() using an inner join to the table representing the map, adding a condition on the key and returning the value.

Parameters:

stmt - SQLStatement

mapExpr - The map expression

keyValExpr - The key value expression

Returns:

The value expression