org.hibernate.criterion

Class Projections

java.lang.Object

org.hibernate.criterion.Projections

public final class Projections
extends Object

The criterion package may be used by applications as a framework for building new kinds of Projection. However, it is intended that most applications will simply use the built-in projection types via the static factory methods of this class. The factory methods that take an alias allow the projected value to be referred to by criterion and order instances. See also the Restrictions factory methods for generating Criterion instances

Author:

Gavin King, Steve Ebersole

See Also:

Criteria

Method Summary

Modifier and Type	Method and Description
static Projection	alias(Projection projection, String alias) Assign an alias to a projection, by wrapping it
static AggregateProjection	avg(String propertyName) A property average value projection
static CountProjection	count(String propertyName) A property value count projection
static CountProjection	countDistinct(String propertyName) A distinct property value count projection
static Projection	distinct(Projection projection) Create a distinct projection from a projection.
static PropertyProjection	groupProperty(String propertyName) A grouping property value projection
static IdentifierProjection	id() An identifier value projection.
static AggregateProjection	max(String propertyName) A property maximum value projection
static AggregateProjection	min(String propertyName) A property minimum value projection
static ProjectionList	projectionList() Create a new projection list.
static PropertyProjection	property(String propertyName) A property value projection
static Projection	rowCount() The query row count, ie.
static Projection	sqlGroupProjection(String sql, String groupBy, String[] columnAliases, Type[] types) A grouping SQL projection, specifying both select clause and group by clause fragments
static Projection	sqlProjection(String sql, String[] columnAliases, Type[] types) A SQL projection, a typed select clause fragment
static AggregateProjection	sum(String propertyName) A property value sum projection

Methods inherited from class java.lang.Object

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

Method Detail

property

public static PropertyProjection property(String propertyName)

A property value projection

Parameters:

propertyName - The name of the property whose values should be projected

Returns:

The property projection

See Also:

PropertyProjection

groupProperty

public static PropertyProjection groupProperty(String propertyName)

A grouping property value projection

Parameters:

propertyName - The name of the property to group

Returns:

The grouped projection

See Also:

PropertyProjection

id

public static IdentifierProjection id()

An identifier value projection.

Returns:

The identifier projection

See Also:

IdentifierProjection

distinct

public static Projection distinct(Projection projection)

Create a distinct projection from a projection.

Parameters:

projection - The project to treat distinctly

Returns:

The distinct projection

See Also:

Distinct

projectionList

public static ProjectionList projectionList()

Create a new projection list.

Returns:

The projection list

rowCount

public static Projection rowCount()

The query row count, ie. count(*)

Returns:

The projection representing the row count

See Also:

RowCountProjection

count

public static CountProjection count(String propertyName)

A property value count projection

Parameters:

propertyName - The name of the property to count over

Returns:

The count projection

See Also:

CountProjection

countDistinct

public static CountProjection countDistinct(String propertyName)

A distinct property value count projection

Parameters:

propertyName - The name of the property to count over

Returns:

The count projection

See Also:

CountProjection

max

public static AggregateProjection max(String propertyName)

A property maximum value projection

Parameters:

propertyName - The property for which to find the max

Returns:

the max projection

See Also:

AggregateProjection

min

public static AggregateProjection min(String propertyName)

A property minimum value projection

Parameters:

propertyName - The property for which to find the min

Returns:

the min projection

See Also:

AggregateProjection

avg

public static AggregateProjection avg(String propertyName)

A property average value projection

Parameters:

propertyName - The property over which to find the average

Returns:

the avg projection

See Also:

AvgProjection

sum

public static AggregateProjection sum(String propertyName)

A property value sum projection

Parameters:

propertyName - The property over which to sum

Returns:

the sum projection

See Also:

AggregateProjection

alias

public static Projection alias(Projection projection,
                               String alias)

Assign an alias to a projection, by wrapping it

Parameters:

projection - The projection to be aliased

alias - The alias to apply

Returns:

The aliased projection

See Also:

AliasedProjection

sqlProjection

public static Projection sqlProjection(String sql,
                                       String[] columnAliases,
                                       Type[] types)

A SQL projection, a typed select clause fragment

Parameters:

sql - The SQL fragment

columnAliases - The column aliases

types - The resulting types

Returns:

The SQL projection

See Also:

SQLProjection

sqlGroupProjection

public static Projection sqlGroupProjection(String sql,
                                            String groupBy,
                                            String[] columnAliases,
                                            Type[] types)

A grouping SQL projection, specifying both select clause and group by clause fragments

Parameters:

sql - The SQL SELECT fragment

groupBy - The SQL GROUP BY fragment

columnAliases - The column aliases

types - The resulting types

Returns:

The SQL projection

See Also:

SQLProjection