org.hibernate.criterion
Class SimpleProjection

java.lang.Object
  org.hibernate.criterion.SimpleProjection

All Implemented Interfaces:

java.io.Serializable, Projection

Direct Known Subclasses:

AggregateProjection, IdentifierProjection, PropertyProjection, RowCountProjection

public abstract class SimpleProjection
extends java.lang.Object
implements Projection

A single-column projection that may be aliased

Author:

Gavin King

See Also:

Serialized Form

Constructor Summary

SimpleProjection()

Method Summary

Projection	as(java.lang.String alias)
java.lang.String[]	getAliases() Get the criteria-level aliases for this projection (ie.
java.lang.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).
java.lang.String[]	getColumnAliases(java.lang.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(java.lang.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
java.lang.String	toGroupSqlString(Criteria criteria, CriteriaQuery criteriaQuery) Render the SQL fragment to be used in the GROUP BY clause

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.hibernate.criterion.Projection

getTypes, toSqlString

Constructor Detail

SimpleProjection

public SimpleProjection()

Method Detail

as

public Projection as(java.lang.String alias)

getColumnAliases

public java.lang.String[] getColumnAliases(java.lang.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.

getTypes

public Type[] getTypes(java.lang.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 java.lang.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.

getAliases

public java.lang.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

toGroupSqlString

public java.lang.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

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.