org.hibernate.criterion
Class Distinct

java.lang.Object
  org.hibernate.criterion.Distinct

All Implemented Interfaces:

Serializable, Projection

public class Distinct
extends Object
implements Projection

Author:

Gavin King

See Also:

Serialized Form

Constructor Summary

Distinct(Projection proj)

Method Summary

String[]	getAliases() Get the criteria-level aliases for this projection (ie.
String[]	getColumnAliases(int loc) Get the SQL column aliases used by this projection for the columns it writes for inclusion into the SELECT clause (Projection.toSqlString(org.hibernate.Criteria, int, org.hibernate.criterion.CriteriaQuery).
String[]	getColumnAliases(String alias, int loc) Get the SQL column aliases used by this projection for the columns it writes for inclusion into the SELECT clause (Projection.toSqlString(org.hibernate.Criteria, int, org.hibernate.criterion.CriteriaQuery) for a particular criteria-level alias.
Type[]	getTypes(Criteria criteria, CriteriaQuery criteriaQuery) Types returned by the rendered SQL fragment.
Type[]	getTypes(String alias, Criteria criteria, CriteriaQuery criteriaQuery) Get the return types for a particular user-visible alias.
boolean	isGrouped() Is this projection fragment (SELECT clause) also part of the GROUP BY
String	toGroupSqlString(Criteria criteria, CriteriaQuery criteriaQuery) Render the SQL fragment to be used in the GROUP BY clause
String	toSqlString(Criteria criteria, int position, CriteriaQuery criteriaQuery) Render the SQL fragment to be used in the SELECT clause.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Distinct

public Distinct(Projection proj)

Method Detail

toSqlString

public String toSqlString(Criteria criteria,
                          int position,
                          CriteriaQuery criteriaQuery)
                   throws HibernateException

Description copied from interface: Projection

Render the SQL fragment to be used in the SELECT clause.

Specified by:

toSqlString in interface Projection

Parameters:

criteria - The local criteria to which this project is attached (for resolution).

position - The number of columns rendered in the SELECT clause before this projection. Generally speaking this is useful to ensure uniqueness of the individual columns aliases.

criteriaQuery - The overall criteria query instance.

Returns:

The SQL fragment to plug into the SELECT

Throws:

HibernateException - Indicates a problem performing the rendering

toGroupSqlString

public String toGroupSqlString(Criteria criteria,
                               CriteriaQuery criteriaQuery)
                        throws HibernateException

Description copied from interface: Projection

Render the SQL fragment to be used in the GROUP BY clause

Specified by:

toGroupSqlString in interface Projection

Parameters:

criteria - The local criteria to which this project is attached (for resolution).

criteriaQuery - The overall criteria query instance.

Returns:

The SQL fragment to plug into the GROUP BY

Throws:

HibernateException - Indicates a problem performing the rendering

getTypes

public Type[] getTypes(Criteria criteria,
                       CriteriaQuery criteriaQuery)
                throws HibernateException

Description copied from interface: Projection

Types returned by the rendered SQL fragment. In other words what are the types that would represent the values this projection asked to be pulled into the result set?

Specified by:

getTypes in interface Projection

Parameters:

criteria - The local criteria to which this project is attached (for resolution).

criteriaQuery - The overall criteria query instance.

Returns:

The return types.

Throws:

HibernateException - Indicates a problem resolving the types

getTypes

public Type[] getTypes(String alias,
                       Criteria criteria,
                       CriteriaQuery criteriaQuery)
                throws HibernateException

Description copied from interface: Projection

Get the return types for a particular user-visible alias.

Differs from Projection.getTypes(org.hibernate.Criteria, CriteriaQuery) in that here we are only interested in the types related to the given criteria-level alias.

Specified by:

getTypes in interface Projection

Parameters:

alias - The criteria-level alias for which to find types.

criteria - The local criteria to which this project is attached (for resolution).

criteriaQuery - The overall criteria query instance.

Returns:

The return types; expected to return null if this projection does not understand this alias.

Throws:

HibernateException - Indicates a problem resolving the types

getColumnAliases

public String[] getColumnAliases(int loc)

Description copied from interface: Projection

Get the SQL column aliases used by this projection for the columns it writes for inclusion into the SELECT clause (Projection.toSqlString(org.hibernate.Criteria, int, org.hibernate.criterion.CriteriaQuery). Hibernate always uses column aliases to extract data from the JDBC ResultSet, so it is important that these be implemented correctly in order for Hibernate to be able to extract these val;ues correctly.

Specified by:

getColumnAliases in interface Projection

Parameters:

loc - Just as in Projection.toSqlString(org.hibernate.Criteria, int, org.hibernate.criterion.CriteriaQuery), represents the number of columns rendered prior to this projection.

Returns:

The columns aliases.

getColumnAliases

public String[] getColumnAliases(String alias,
                                 int loc)

Description copied from interface: Projection

Get the SQL column aliases used by this projection for the columns it writes for inclusion into the SELECT clause (Projection.toSqlString(org.hibernate.Criteria, int, org.hibernate.criterion.CriteriaQuery) for a particular criteria-level alias.

Specified by:

getColumnAliases in interface Projection

Parameters:

alias - The criteria-level alias

loc - Just as in Projection.toSqlString(org.hibernate.Criteria, int, org.hibernate.criterion.CriteriaQuery), represents the number of columns rendered prior to this projection.

Returns:

The columns aliases pertaining to a particular criteria-level alias; expected to return null if this projection does not understand this alias.

getAliases

public String[] getAliases()

Description copied from interface: Projection

Get the criteria-level aliases for this projection (ie. the ones that will be passed to the ResultTransformer)

Specified by:

getAliases in interface Projection

Returns:

The aliases

isGrouped

public boolean isGrouped()

Description copied from interface: Projection

Is this projection fragment (SELECT clause) also part of the GROUP BY

Specified by:

isGrouped in interface Projection

Returns:

True if the projection is also part of the GROUP BY; false otherwise.

toString

public String toString()

Overrides:

toString in class Object