net.sf.basedb.core
Class ExtraValueJoin

java.lang.Object
  net.sf.basedb.core.ExtraValueJoin

All Implemented Interfaces:

Join, QueryElement

 class ExtraValueJoin
extends Object
implements Join

Represents a join to an extra value in a dynamic query: leftTable JOIN extraValueTable ON ...

This class is used by, for example, DynamicSpotQuery.joinExtraValue(ExtraValue, JoinType) to create the Join query element that is needed. After the extra value has been join it can be used in expressions in the query.

Version:

2.0

Author:

Nicklas

See Also:

ExtraValueExpression, Dynamic.extraValue(ExtraValue)

Last modified

$Date: 2010-04-21 11:48:29 +0200 (Wed, 21 Apr 2010) $

Field Summary

private VirtualColumn[]	columns
private ExtraValue	extraValue
private JoinType	joinType
private VirtualTable	left
private VirtualTable	right
private VirtualDb	vdb

Constructor Summary

ExtraValueJoin(ExtraValue extraValue, JoinType joinType)
Create a new join using the root entity table as the left table.

Method Summary

boolean	equals(Object other) This join is equal to another ExtraValueJoin if they join to the same extra value with the same join type.
Collection<? extends QueryElement>	getChildren() Get the children of this query element or null if it has no children.
String	getThetaJoin(Query query, DbControl dc)
String	getThetaJoinCondition(Query query, DbControl dc)
int	hashCode()
String	toQl(Query query, DbControl dc) Create a query language string of the query element.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

extraValue

private final ExtraValue extraValue

vdb

private final VirtualDb vdb

joinType

private final JoinType joinType

left

private final VirtualTable left

right

private final VirtualTable right

columns

private final VirtualColumn[] columns

Constructor Detail

ExtraValueJoin

ExtraValueJoin(ExtraValue extraValue,
               JoinType joinType)

Create a new join using the root entity table as the left table. SELECT ... FROM rootTable JOIN extraValueTable.

The extra value table and which columns should be used in the join is found by examining the extra value properties, ie. value type and coordinate type.

Parameters:

extraValue - The extra value to join

joinType - The type of join

Method Detail

toQl

public String toQl(Query query,
                   DbControl dc)
            throws BaseException

Description copied from interface: QueryElement

Create a query language string of the query element. Use the Query.getQueryType() method to find out which query language is wanted in case the element requires different syntax for different languages.

Specified by:

toQl in interface QueryElement

Parameters:

query - The query that is about to be executed

dc - The DbControl object used to execute the query

Throws:

BaseException - If there is any other error

getChildren

public Collection<? extends QueryElement> getChildren()

Description copied from interface: QueryElement

Get the children of this query element or null if it has no children. For example the AddExpression has two children, the expression beeing added.

Specified by:

getChildren in interface QueryElement

Returns:

Always null

getThetaJoin

public String getThetaJoin(Query query,
                           DbControl dc)
                    throws BaseException

Specified by:

getThetaJoin in interface Join

Throws:

BaseException

getThetaJoinCondition

public String getThetaJoinCondition(Query query,
                                    DbControl dc)
                             throws BaseException

Specified by:

getThetaJoinCondition in interface Join

Throws:

BaseException

toString

public String toString()

Overrides:

toString in class Object

equals

public boolean equals(Object other)

This join is equal to another ExtraValueJoin if they join to the same extra value with the same join type.

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object