com.mysema.query

Interface Projectable

All Known Subinterfaces:

JDOQLQuery, JPQLQuery

All Known Implementing Classes:

AbstractCollQuery, AbstractHibernateQuery, AbstractHibernateSQLQuery, AbstractJDOQuery, AbstractJPAQuery, AbstractJPASQLQuery, AbstractSQLQuery, AbstractSQLQuery, AbstractSQLQuery, CollQuery, HibernateQuery, HibernateSQLQuery, JDOQuery, JDOSQLQuery, JPAQuery, JPAQueryBase, JPASQLQuery, MySQLQuery, OracleQuery, PostgresQuery, ProjectableAdapter, ProjectableQuery, ProjectableSQLQuery, SQLQuery, SQLServerQuery, TeradataQuery

public interface Projectable

Projectable defines default projection methods for Query implementations. All Querydsl query implementations should implement either this interface or SimpleProjectable.

Author:

tiwe

See Also:

SimpleProjectable

Method Summary

Modifier and Type	Method and Description
long	count() return the amount of matched rows
boolean	exists()
com.mysema.commons.lang.CloseableIterator<Tuple>	iterate(Expression<?>... args) iterate over the results for the given projection
<RT> com.mysema.commons.lang.CloseableIterator<RT>	iterate(Expression<RT> projection) iterate over the results for the given projection
List<Tuple>	list(Expression<?>... args) list the results for the given projection An empty list is returned for no results.
<RT> List<RT>	list(Expression<RT> projection) list the results for the given projection An empty list is returned for no results.
SearchResults<Tuple>	listResults(Expression<?>... args) list the results for the given projection
<RT> SearchResults<RT>	listResults(Expression<RT> projection) list the results for the given projection
<K,V> Map<K,V>	map(Expression<K> key, Expression<V> value) return the given projection as a Map instance using key and value for Map population An empty map is returned for no results.
boolean	notExists()
Tuple	singleResult(Expression<?>... args) return a single result for the given projection or null if no result is found
<RT> RT	singleResult(Expression<RT> projection) return a single result for the given projection or null if no result is found
<T> T	transform(ResultTransformer<T> transformer) Apply the given transformer to this Projectable instance and return the results
Tuple	uniqueResult(Expression<?>... args) return a unique result for the given projection or null if no result is found
<RT> RT	uniqueResult(Expression<RT> projection) return a unique result for the given projection or null if no result is found

Method Detail

count

@Nonnegative
long count()

return the amount of matched rows

exists

boolean exists()

Returns:

true, if rows matching the given criteria exist, otherwise false

notExists

boolean notExists()

Returns:

true, if no rows matching the given criteria exist, otherwise false

iterate

com.mysema.commons.lang.CloseableIterator<Tuple> iterate(Expression<?>... args)

iterate over the results for the given projection

Parameters:

args -

Returns:

iterate

<RT> com.mysema.commons.lang.CloseableIterator<RT> iterate(Expression<RT> projection)

iterate over the results for the given projection

Type Parameters:

RT - generic type of the Iterator

Parameters:

projection -

Returns:

an Iterator over the projection

list

List<Tuple> list(Expression<?>... args)

list the results for the given projection An empty list is returned for no results.

Parameters:

args -

Returns:

list

<RT> List<RT> list(Expression<RT> projection)

list the results for the given projection An empty list is returned for no results.

Type Parameters:

RT - generic type of the List

Parameters:

projection -

Returns:

a List over the projection

listResults

SearchResults<Tuple> listResults(Expression<?>... args)

list the results for the given projection

Parameters:

args -

Returns:

listResults

<RT> SearchResults<RT> listResults(Expression<RT> projection)

list the results for the given projection

Type Parameters:

RT -

Parameters:

projection -

Returns:

map

<K,V> Map<K,V> map(Expression<K> key,
                   Expression<V> value)

return the given projection as a Map instance using key and value for Map population An empty map is returned for no results.

Type Parameters:

K -

V -

Parameters:

key -

value -

Returns:

singleResult

@Nullable
Tuple singleResult(Expression<?>... args)

return a single result for the given projection or null if no result is found

There is some ambiguity for missing results and null valued results, for disambiguation use the list or iterate methods instead.

for multiple results only the first one is returned

Parameters:

args -

Returns:

singleResult

@Nullable
<RT> RT singleResult(Expression<RT> projection)

return a single result for the given projection or null if no result is found

There is some ambiguity for missing results and null valued results, for disambiguation use the list or iterate methods instead.

for multiple results only the first one is returned

Type Parameters:

RT - return type

Parameters:

projection -

Returns:

the result or null for an empty result

transform

<T> T transform(ResultTransformer<T> transformer)

Apply the given transformer to this Projectable instance and return the results

Type Parameters:

T -

Parameters:

transformer -

Returns:

uniqueResult

@Nullable
Tuple uniqueResult(Expression<?>... args)

return a unique result for the given projection or null if no result is found

There is some ambiguity for missing results and null valued results, for disambiguation use the list or iterate methods instead.

Parameters:

args -

Returns:

Throws:

NonUniqueResultException - if there is more than one matching result

uniqueResult

@Nullable
<RT> RT uniqueResult(Expression<RT> projection)

return a unique result for the given projection or null if no result is found

There is some ambiguity for missing results and null valued results, for disambiguation use the list or iterate methods instead.

Type Parameters:

RT - return type

Parameters:

projection -

Returns:

the result or null for an empty result

Throws:

NonUniqueResultException - if there is more than one matching result