net.sf.basedb.core
Class DynamicJoin

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

All Implemented Interfaces:

Join, QueryElement

 class DynamicJoin
extends Object
implements Join

Represents a join between two virtual tables in a dynamic query: leftTable JOIN rightTable ON columns.

This class is used by, for example, DynamicSpotQuery.joinReporters(JoinType) to create the Join query element that is needed.

Version:

2.0

Author:

Nicklas

Last modified

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

Field Summary

private VirtualColumn[]	columns
private int	hashCode
private JoinType	joinType
private VirtualTable	left
private VirtualTable	right
private VirtualDb	vdb

Constructor Summary

DynamicJoin(VirtualDb vdb, JoinType joinType, VirtualTable right, VirtualColumn... columns)
Create a new join using the root entity table as the left table.

DynamicJoin(VirtualDb vdb, JoinType joinType, VirtualTable left, VirtualTable right, VirtualColumn... columns)
Create a new join between two tables.

Method Summary

boolean	equals(Object other) This join is equal to another DynamicJoin if they join between the same tables using the same columns and join types.
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

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

hashCode

private int hashCode

Constructor Detail

DynamicJoin

DynamicJoin(VirtualDb vdb,
            JoinType joinType,
            VirtualTable right,
            VirtualColumn... columns)

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

Parameters:

vdb - The virtual database where the joined table is located

joinType - The type of join

right - The table to join to

columns - The columns to join on, all columns must exists in the root table and the joined table

DynamicJoin

DynamicJoin(VirtualDb vdb,
            JoinType joinType,
            VirtualTable left,
            VirtualTable right,
            VirtualColumn... columns)

Create a new join between two tables. The left table must already have been joined to the root table or to another joined table. SELECT ... FROM rootTable ... JOIN left ... JOIN right ON columns

Parameters:

vdb - The virtual database where the joined table is located

joinType - The type of join

left - The table to join from

right - The table to join to

columns - The columns to join on, all columns must exists in the left table and the right table

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 DynamicJoin if they join between the same tables using the same columns and join types.

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object