Package org.apache.cayenne.query

Class SelectById<T>

java.lang.Object

org.apache.cayenne.query.IndirectQuery

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

All Implemented Interfaces:

Serializable, Query, Select<T>

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

A query to select objects by id.

Since:

4.0

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static interface	SelectById.IdSpec
protected static class	SelectById.MultiMapIdSpec
protected static class	SelectById.MultiScalarIdSpec
protected static interface	SelectById.QueryRoot
protected static class	SelectById.SingleMapIdSpec
protected static class	SelectById.SingleScalarIdSpec

Field Summary

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

dataMap, lastResolver, name, replacementQuery

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	SelectById(SelectById.QueryRoot root, SelectById.IdSpec idSpec)
protected	SelectById(SelectById.QueryRoot root, SelectById.IdSpec idSpec, boolean fetchingDataRows)

Method Summary

Modifier and Type	Method	Description
ResultBatchIterator<T>	batchIterator(ObjectContext context, int size)	Creates a ResultBatchIterator based on the provided context and batch size.
SelectById<T>	cacheGroup(String cacheGroup)
SelectById<T>	cacheStrategy(QueryCacheStrategy strategy)
SelectById<T>	cacheStrategy(QueryCacheStrategy strategy, String cacheGroup)
protected Query	createReplacementQuery(EntityResolver resolver)	Creates a substitute query.
static SelectById<DataRow>	dataRowQuery(Class<?> entityType, Object id)
static SelectById<DataRow>	dataRowQuery(Class<?> entityType, Object firstId, Object... otherIds)
static SelectById<DataRow>	dataRowQuery(Class<?> entityType, Map<String,?> id)
static SelectById<DataRow>	dataRowQuery(Class<?> entityType, Map<String,?> firstId, Map<String,?>... otherIds)
static SelectById<DataRow>	dataRowQuery(ObjectId id)
static SelectById<DataRow>	dataRowQuery(ObjectId firstId, ObjectId... otherIds)
String	getCacheGroup()
QueryCacheStrategy	getCacheStrategy()
PrefetchTreeNode	getPrefetches()
boolean	isFetchingDataRows()
void	iterate(ObjectContext context, ResultIteratorCallback<T> callback)	Creates a ResultIterator based on the provided context and passes it to a callback for processing.
ResultIterator<T>	iterator(ObjectContext context)	Creates a ResultIterator based on the provided context.
SelectById<T>	localCache()	Instructs Cayenne to look for query results in the "local" cache when running the query.
SelectById<T>	localCache(String cacheGroup)	Instructs Cayenne to look for query results in the "local" cache when running the query.
SelectById<T>	prefetch(String path, int semantics)	Merges a prefetch path with specified semantics into the query prefetch tree.
SelectById<T>	prefetch(PrefetchTreeNode prefetch)	Merges prefetch into the query prefetch tree.
static <T> SelectById<T>	query(Class<T> entityType, Object id)
static <T> SelectById<T>	query(Class<T> entityType, Object firstId, Object... otherIds)
static <T> SelectById<T>	query(Class<T> entityType, Collection<Object> ids)
static <T> SelectById<T>	query(Class<T> entityType, Map<String,?> id)
static <T> SelectById<T>	query(Class<T> entityType, Map<String,?> firstId, Map<String,?>... otherIds)
static <T> SelectById<T>	query(Class<T> entityType, ObjectId id)
static <T> SelectById<T>	query(Class<T> entityType, ObjectId firstId, ObjectId... otherIds)
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.
SelectById<T>	sharedCache()	Instructs Cayenne to look for query results in the "shared" cache when running the query.
SelectById<T>	sharedCache(String cacheGroup)	Instructs Cayenne to look for query results in the "shared" cache when running the query.

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

createSQLAction, getMetaData, getReplacementQuery, route

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, getMetaData, route

Constructor Detail

SelectById

protected SelectById(SelectById.QueryRoot root,
                     SelectById.IdSpec idSpec,
                     boolean fetchingDataRows)

SelectById

protected SelectById(SelectById.QueryRoot root,
                     SelectById.IdSpec idSpec)

Method Detail

query

public static <T> SelectById<T> query(Class<T> entityType,
                                      Object id)

query

public static <T> SelectById<T> query(Class<T> entityType,
                                      Map<String,?> id)

query

public static <T> SelectById<T> query(Class<T> entityType,
                                      ObjectId id)

query

public static <T> SelectById<T> query(Class<T> entityType,
                                      Object firstId,
                                      Object... otherIds)

Since:

4.2

query

public static <T> SelectById<T> query(Class<T> entityType,
                                      Collection<Object> ids)

Since:

4.2

query

@SafeVarargs
public static <T> SelectById<T> query(Class<T> entityType,
                                      Map<String,?> firstId,
                                      Map<String,?>... otherIds)

Since:

4.2

query

public static <T> SelectById<T> query(Class<T> entityType,
                                      ObjectId firstId,
                                      ObjectId... otherIds)

Since:

4.2

dataRowQuery

public static SelectById<DataRow> dataRowQuery(Class<?> entityType,
                                               Object id)

dataRowQuery

public static SelectById<DataRow> dataRowQuery(Class<?> entityType,
                                               Map<String,?> id)

dataRowQuery

public static SelectById<DataRow> dataRowQuery(ObjectId id)

dataRowQuery

public static SelectById<DataRow> dataRowQuery(Class<?> entityType,
                                               Object firstId,
                                               Object... otherIds)

Since:

4.2

dataRowQuery

@SafeVarargs
public static SelectById<DataRow> dataRowQuery(Class<?> entityType,
                                               Map<String,?> firstId,
                                               Map<String,?>... otherIds)

Since:

4.2

dataRowQuery

public static SelectById<DataRow> dataRowQuery(ObjectId firstId,
                                               ObjectId... otherIds)

Since:

4.2

select

public List<T> select(ObjectContext context)

Description copied from interface: Select

Selects objects using provided context.

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

Specified by:

select in interface Select<T>

selectOne

public T selectOne(ObjectContext context)

Description copied from interface: Select

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)".

Specified by:

selectOne in interface Select<T>

selectFirst

public T selectFirst(ObjectContext context)

Description copied from interface: Select

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 Select.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.

Selecting the first object via "Select.selectFirst(ObjectContext)" is more comprehensible than selecting via "ObjectContext.selectFirst(Select)", because implementations of "Select" set fetch size limit to one.

Specified by:

selectFirst in interface Select<T>

iterate

public void iterate(ObjectContext context,
                    ResultIteratorCallback<T> callback)

Description copied from interface: Select

Creates a ResultIterator based on the provided context and passes it to a callback for processing. The caller does not need to worry about closing the iterator. This method takes care of it.

Essentially the inversion of "ObjectContext.iterate(Select, ResultIteratorCallback)".

Specified by:

iterate in interface Select<T>

iterator

public ResultIterator<T> iterator(ObjectContext context)

Description copied from interface: Select

Creates a ResultIterator based on the provided context. It is usually backed by an open result set and is useful for processing of large data sets, preserving a constant memory footprint. The caller must wrap iteration in try/finally (or try-with-resources for Java 1.7 and higher) and close the ResultIterator explicitly. Or use Select.iterate(ObjectContext, ResultIteratorCallback) as an alternative.

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

Specified by:

iterator in interface Select<T>

batchIterator

public ResultBatchIterator<T> batchIterator(ObjectContext context,
                                            int size)

Description copied from interface: Select

Creates a ResultBatchIterator based on the provided context and batch size. It is usually backed by an open result set and is useful for processing of large data sets, preserving a constant memory footprint. The caller must wrap iteration in try/finally (or try-with-resources for Java 1.7 and higher) and close the ResultBatchIterator explicitly.

Specified by:

batchIterator in interface Select<T>

localCache

public SelectById<T> localCache(String cacheGroup)

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, cacheGroup);
 

localCache

public SelectById<T> localCache()

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);
 

sharedCache

public SelectById<T> sharedCache(String cacheGroup)

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, cacheGroup);
 

sharedCache

public SelectById<T> sharedCache()

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);
 

getCacheStrategy

public QueryCacheStrategy getCacheStrategy()

cacheStrategy

public SelectById<T> cacheStrategy(QueryCacheStrategy strategy)

cacheStrategy

public SelectById<T> cacheStrategy(QueryCacheStrategy strategy,
                                   String cacheGroup)

getCacheGroup

public String getCacheGroup()

cacheGroup

public SelectById<T> cacheGroup(String cacheGroup)

isFetchingDataRows

public boolean isFetchingDataRows()

prefetch

public SelectById<T> prefetch(PrefetchTreeNode prefetch)

Merges prefetch into the query prefetch tree.

Returns:

this object

prefetch

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

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

Returns:

this object

getPrefetches

public PrefetchTreeNode getPrefetches()

createReplacementQuery

protected Query createReplacementQuery(EntityResolver resolver)

Description copied from class: IndirectQuery

Creates a substitute query. An implementor is free to provide an arbitrary replacement query.

Specified by:

createReplacementQuery in class IndirectQuery