org.apache.cayenne.query

Class ObjectSelect<T>

java.lang.Object

org.apache.cayenne.query.IndirectQuery

org.apache.cayenne.query.ObjectSelect<T>

All Implemented Interfaces:

Serializable, ConfigurationNode, Query, Select<T>

public class ObjectSelect<T>
extends IndirectQuery
implements Select<T>

A selecting query providing chainable API. Can be viewed as an alternative to SelectQuery.

Since:

4.0

See Also:

Serialized Form

Field Summary

Fields inherited from class org.apache.cayenne.query.IndirectQuery

dataMap, lastResolver, name, replacementQuery

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ObjectSelect()

Method Summary

Methods

Modifier and Type	Method and Description
ObjectSelect<T>	addOrderBy(Collection<Ordering> orderings) Adds new orderings to the list of orderings.
ObjectSelect<T>	addOrderBy(Ordering... orderings) Adds new orderings to the list of the existing orderings.
ObjectSelect<T>	addOrderBy(String property) Adds a single ascending ordering on a given property to the existing ordering clause of this query.
ObjectSelect<T>	addOrderBy(String property, SortOrder sortOrder) Adds a single ordering on a given property to the existing ordering clause of this query.
ObjectSelect<T>	addPrefetch(PrefetchTreeNode prefetch) Merges prefetch into the query prefetch tree.
ObjectSelect<T>	addPrefetch(String path, int semantics) Merges a prefetch path with specified semantics into the query prefetch tree.
ObjectSelect<T>	and(Collection<Expression> expressions) AND's provided expressions to the existing WHERE clause expression.
ObjectSelect<T>	and(Expression... expressions) AND's provided expressions to the existing WHERE clause expression.
ObjectSelect<T>	cacheGroups(Collection<String> cacheGroups)
ObjectSelect<T>	cacheGroups(String... cacheGroups)
ObjectSelect<T>	cacheStrategy(QueryCacheStrategy strategy, String... cacheGroups)
protected Query	createReplacementQuery(EntityResolver resolver) Translates self to a SelectQuery.
static ObjectSelect<DataRow>	dataRowQuery(Class<?> entityType) Creates a ObjectSelect that fetches data for an ObjEntity determined from a provided class.
static ObjectSelect<DataRow>	dataRowQuery(Class<?> entityType, Expression expression) Creates a ObjectSelect that fetches data for an ObjEntity determined from a provided class and uses provided expression for its qualifier.
ObjectSelect<T>	dbEntityName(String dbEntityName) Sets the DbEntity name to fetch without changing the return type of the query.
static ObjectSelect<DataRow>	dbQuery(String dbEntityName) Creates a ObjectSelect that fetches DataRows for a DbEntity determined from provided "dbEntityName".
static ObjectSelect<DataRow>	dbQuery(String dbEntityName, Expression expression) Creates a ObjectSelect that fetches DataRows for a DbEntity determined from provided "dbEntityName" and uses provided expression for its qualifier.
ObjectSelect<T>	entityName(String entityName) Sets the ObjEntity name to fetch without changing the return type of the query.
ObjectSelect<T>	entityType(Class<?> entityType) Sets the type of the entity to fetch without changing the return type of the query.
ObjectSelect<DataRow>	fetchDataRows() Forces query to fetch DataRows.
String[]	getCacheGroups()
QueryCacheStrategy	getCacheStrategy()
String	getDbEntityName()
String	getEntityName()
Class<?>	getEntityType()
int	getLimit()
int	getOffset()
Collection<Ordering>	getOrderings()
int	getPageSize()
PrefetchTreeNode	getPrefetches()
int	getStatementFetchSize()
Expression	getWhere() Returns a WHERE clause Expression of this query.
boolean	isFetchingDataRows()
ObjectSelect<T>	limit(int fetchLimit) Resets query fetch limit - a parameter that defines max number of objects that should be ever be fetched from the database.
ObjectSelect<T>	localCache(String... cacheGroups) Instructs Cayenne to look for query results in the "local" cache when running the query.
ObjectSelect<T>	offset(int fetchOffset) Resets query fetch offset - a parameter that defines how many objects should be skipped when reading data from the database.
ObjectSelect<T>	or(Collection<Expression> expressions) OR's provided expressions to the existing WHERE clause expression.
ObjectSelect<T>	or(Expression... expressions) OR's provided expressions to the existing WHERE clause expression.
ObjectSelect<T>	orderBy(Collection<Ordering> orderings) Initializes or resets a list of orderings of this query.
ObjectSelect<T>	orderBy(Ordering... orderings) Initializes or resets a list of orderings of this query.
ObjectSelect<T>	orderBy(String property) Initializes ordering clause of this query with a single ascending ordering on a given property.
ObjectSelect<T>	orderBy(String property, SortOrder sortOrder) Initializes ordering clause of this query with a single ordering on a given property.
ObjectSelect<T>	pageSize(int pageSize) Resets query page size.
ObjectSelect<T>	prefetch(PrefetchTreeNode prefetch) Resets internal prefetches to the new value.
ObjectSelect<T>	prefetch(String path, int semantics) Resets internal prefetches to the new value, which is a single prefetch with specified semantics.
static <T> ObjectSelect<T>	query(Class<T> entityType) Creates a ObjectSelect that selects objects of a given persistent class.
static <T> ObjectSelect<T>	query(Class<T> entityType, Expression expression) Creates a ObjectSelect that selects objects of a given persistent class and uses provided expression for its qualifier.
static <T> ObjectSelect<T>	query(Class<T> entityType, Expression expression, List<Ordering> orderings) Creates a ObjectSelect that selects objects of a given persistent class and uses provided expression for its qualifier.
static <T> ObjectSelect<T>	query(Class<T> resultType, String entityName) Creates a ObjectSelect that fetches data for ObjEntity determined from provided "entityName", but fetches the result of a provided type.
List<T>	select(ObjectContext context) Selects objects using provided context.
T	selectFirst(ObjectContext context) Selects a single object using provided context.
T	selectOne(ObjectContext context) Selects a single object using provided context.
ObjectSelect<T>	sharedCache(String... cacheGroups) Instructs Cayenne to look for query results in the "shared" cache when running the query.
ObjectSelect<T>	statementFetchSize(int size) Sets fetch size of the PreparedStatement generated for this query.
ObjectSelect<T>	where(Expression expression) Initializes or resets a qualifier expression of this query.
ObjectSelect<T>	where(String expressionString, Object... parameters) Initializes or resets a qualifier expression of this query, using provided expression String and an array of position parameters.

Methods inherited from class org.apache.cayenne.query.IndirectQuery

acceptVisitor, createSQLAction, getDataMap, getMetaData, getName, getReplacementQuery, route, setDataMap, setName

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.cayenne.query.Query

createSQLAction, getDataMap, getMetaData, getName, route

Methods inherited from interface org.apache.cayenne.configuration.ConfigurationNode

acceptVisitor

Constructor Detail

ObjectSelect

protected ObjectSelect()

Method Detail

query

public static <T> ObjectSelect<T> query(Class<T> entityType)

Creates a ObjectSelect that selects objects of a given persistent class.

query

public static <T> ObjectSelect<T> query(Class<T> entityType,
                        Expression expression)

Creates a ObjectSelect that selects objects of a given persistent class and uses provided expression for its qualifier.

query

public static <T> ObjectSelect<T> query(Class<T> entityType,
                        Expression expression,
                        List<Ordering> orderings)

Creates a ObjectSelect that selects objects of a given persistent class and uses provided expression for its qualifier.

dataRowQuery

public static ObjectSelect<DataRow> dataRowQuery(Class<?> entityType)

Creates a ObjectSelect that fetches data for an ObjEntity determined from a provided class.

dataRowQuery

public static ObjectSelect<DataRow> dataRowQuery(Class<?> entityType,
                                 Expression expression)

Creates a ObjectSelect that fetches data for an ObjEntity determined from a provided class and uses provided expression for its qualifier.

query

public static <T> ObjectSelect<T> query(Class<T> resultType,
                        String entityName)

Creates a ObjectSelect that fetches data for ObjEntity determined from provided "entityName", but fetches the result of a provided type. This factory method is most often used with generic classes that by themselves are not enough to resolve the entity to fetch.

dbQuery

public static ObjectSelect<DataRow> dbQuery(String dbEntityName)

Creates a ObjectSelect that fetches DataRows for a DbEntity determined from provided "dbEntityName".

dbQuery

public static ObjectSelect<DataRow> dbQuery(String dbEntityName,
                            Expression expression)

Creates a ObjectSelect that fetches DataRows for a DbEntity determined from provided "dbEntityName" and uses provided expression for its qualifier.

Returns:

this object

createReplacementQuery

protected Query createReplacementQuery(EntityResolver resolver)

Translates self to a SelectQuery.

Specified by:

createReplacementQuery in class IndirectQuery

entityType

public ObjectSelect<T> entityType(Class<?> entityType)

Sets the type of the entity to fetch without changing the return type of the query.

Returns:

this object

entityName

public ObjectSelect<T> entityName(String entityName)

Sets the ObjEntity name to fetch without changing the return type of the query. This form is most often used for generic entities that don't map to a distinct class.

Returns:

this object

dbEntityName

public ObjectSelect<T> dbEntityName(String dbEntityName)

Sets the DbEntity name to fetch without changing the return type of the query. This form is most often used for generic entities that don't map to a distinct class.

Returns:

this object

fetchDataRows

public ObjectSelect<DataRow> fetchDataRows()

Forces query to fetch DataRows. This automatically changes whatever result type was set previously to "DataRow".

Returns:

this object

where

public ObjectSelect<T> where(Expression expression)

Initializes or resets a qualifier expression of this query.

Returns:

this object

where

public ObjectSelect<T> where(String expressionString,
                    Object... parameters)

Initializes or resets a qualifier expression of this query, using provided expression String and an array of position parameters.

Returns:

this object

and

public ObjectSelect<T> and(Expression... expressions)

AND's provided expressions to the existing WHERE clause expression.

Returns:

this object

and

public ObjectSelect<T> and(Collection<Expression> expressions)

AND's provided expressions to the existing WHERE clause expression.

Returns:

this object

or

public ObjectSelect<T> or(Expression... expressions)

OR's provided expressions to the existing WHERE clause expression.

Returns:

this object

or

public ObjectSelect<T> or(Collection<Expression> expressions)

OR's provided expressions to the existing WHERE clause expression.

Returns:

this object

orderBy

public ObjectSelect<T> orderBy(String property)

Initializes ordering clause of this query with a single ascending ordering on a given property.

Returns:

this object

orderBy

public ObjectSelect<T> orderBy(String property,
                      SortOrder sortOrder)

Initializes ordering clause of this query with a single ordering on a given property.

Returns:

this object

orderBy

public ObjectSelect<T> orderBy(Ordering... orderings)

Initializes or resets a list of orderings of this query.

Returns:

this object

orderBy

public ObjectSelect<T> orderBy(Collection<Ordering> orderings)

Initializes or resets a list of orderings of this query.

Returns:

this object

addOrderBy

public ObjectSelect<T> addOrderBy(String property)

Adds a single ascending ordering on a given property to the existing ordering clause of this query.

Returns:

this object

addOrderBy

public ObjectSelect<T> addOrderBy(String property,
                         SortOrder sortOrder)

Adds a single ordering on a given property to the existing ordering clause of this query.

Returns:

this object

addOrderBy

public ObjectSelect<T> addOrderBy(Ordering... orderings)

Adds new orderings to the list of the existing orderings.

Returns:

this object

addOrderBy

public ObjectSelect<T> addOrderBy(Collection<Ordering> orderings)

Adds new orderings to the list of orderings.

Returns:

this object

prefetch

public ObjectSelect<T> prefetch(String path,
                       int semantics)

Resets internal prefetches to the new value, which is a single prefetch with specified semantics.

Returns:

this object

prefetch

public ObjectSelect<T> prefetch(PrefetchTreeNode prefetch)

Resets internal prefetches to the new value.

Returns:

this object

addPrefetch

public ObjectSelect<T> addPrefetch(PrefetchTreeNode prefetch)

Merges prefetch into the query prefetch tree.

Returns:

this object

addPrefetch

public ObjectSelect<T> addPrefetch(String path,
                          int semantics)

Merges a prefetch path with specified semantics into the query prefetch tree.

Returns:

this object

limit

public ObjectSelect<T> limit(int fetchLimit)

Resets query fetch limit - a parameter that defines max number of objects that should be ever be fetched from the database.

offset

public ObjectSelect<T> offset(int fetchOffset)

Resets query fetch offset - a parameter that defines how many objects should be skipped when reading data from the database.

pageSize

public ObjectSelect<T> pageSize(int pageSize)

Resets query page size. A non-negative page size enables query result pagination that saves memory and processing time for large lists if only parts of the result are ever going to be accessed.

statementFetchSize

public ObjectSelect<T> statementFetchSize(int size)

Sets fetch size of the PreparedStatement generated for this query. Only non-negative values would change the default size.

See Also:

Statement.setFetchSize(int)

cacheStrategy

public ObjectSelect<T> cacheStrategy(QueryCacheStrategy strategy,
                            String... cacheGroups)

cacheGroups

public ObjectSelect<T> cacheGroups(String... cacheGroups)

cacheGroups

public ObjectSelect<T> cacheGroups(Collection<String> cacheGroups)

localCache

public ObjectSelect<T> localCache(String... cacheGroups)

Instructs Cayenne to look for query results in the "local" cache when running the query. This is a short-hand notation for:

 query.cacheStrategy(QueryCacheStrategy.LOCAL_CACHE, cacheGroups);
 

sharedCache

public ObjectSelect<T> sharedCache(String... cacheGroups)

Instructs Cayenne to look for query results in the "shared" cache when running the query. This is a short-hand notation for:

 query.cacheStrategy(QueryCacheStrategy.SHARED_CACHE, cacheGroups);
 

getCacheGroups

public String[] getCacheGroups()

getCacheStrategy

public QueryCacheStrategy getCacheStrategy()

getStatementFetchSize

public int getStatementFetchSize()

getPageSize

public int getPageSize()

getLimit

public int getLimit()

getOffset

public int getOffset()

isFetchingDataRows

public boolean isFetchingDataRows()

getEntityType

public Class<?> getEntityType()

getEntityName

public String getEntityName()

getDbEntityName

public String getDbEntityName()

getWhere

public Expression getWhere()

Returns a WHERE clause Expression of this query.

getOrderings

public Collection<Ordering> getOrderings()

getPrefetches

public PrefetchTreeNode getPrefetches()

select

public List<T> select(ObjectContext context)

Selects objects using provided context. Essentially the inversion of "ObjectContext.select(query)".

selectOne

public T selectOne(ObjectContext context)

Selects a single object using provided context. The query is expected to match zero or one object. It returns null if no objects were matched. If query matched more than one object, CayenneRuntimeException is thrown.

Essentially the inversion of "ObjectContext.selectOne(Select)".

selectFirst

public T selectFirst(ObjectContext context)

Selects a single object using provided context. The query itself can match any number of objects, but will return only the first one. It returns null if no objects were matched.

If it matched more than one object, the first object from the list is returned. This makes 'selectFirst' different from selectOne(ObjectContext), which would throw in this situation. 'selectFirst' is useful e.g. when the query is ordered and we only want to see the first object (e.g. "most recent news article"), etc.

This method is equivalent to calling "limit(1).selectOne(context)".