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

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

All Implemented Interfaces:

SQLMethod

public class MapGetMethod
extends AbstractSQLMethod

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

Field Summary

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

clr, exprFactory, LOCALISER, stmt

Constructor Summary

MapGetMethod()

Method Summary

protected SQLExpression	getAsInnerJoin(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(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(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

MapGetMethod

public MapGetMethod()

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(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:

mapExpr - The map expression

keyValExpr - The key value expression

Returns:

The value expression

getAsInnerJoin

protected SQLExpression getAsInnerJoin(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:

mapExpr - The map expression

keyValExpr - The key value expression

Returns:

The value expression