Class SelectById<T>
- java.lang.Object
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- org.apache.cayenne.query.IndirectQuery
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- org.apache.cayenne.query.SelectById<T>
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- All Implemented Interfaces:
Serializable
,Query
,Select<T>
public class SelectById<T> extends IndirectQuery implements Select<T>
A query to select single objects by id.- Since:
- 4.0
- See Also:
- Serialized Form
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Field Summary
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Fields inherited from class org.apache.cayenne.query.IndirectQuery
dataMap, lastResolver, name, replacementQuery
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Constructor Summary
Constructors Constructor Description SelectById()
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods 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, Map<String,Object> id)
static SelectById<DataRow>
dataRowQuery(ObjectId id)
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, Map<String,?> id)
static <T> SelectById<T>
query(Class<T> entityType, ObjectId id)
protected ObjEntity
resolveEntity(EntityResolver resolver)
protected Map<String,?>
resolveId(ObjEntity entity)
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
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface org.apache.cayenne.query.Query
createSQLAction, getMetaData, route
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Method Detail
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query
public static <T> SelectById<T> query(Class<T> entityType, Object id)
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query
public static <T> SelectById<T> query(Class<T> entityType, Map<String,?> id)
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query
public static <T> SelectById<T> query(Class<T> entityType, ObjectId id)
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dataRowQuery
public static SelectById<DataRow> dataRowQuery(Class<?> entityType, Object id)
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dataRowQuery
public static SelectById<DataRow> dataRowQuery(Class<?> entityType, Map<String,Object> id)
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dataRowQuery
public static SelectById<DataRow> dataRowQuery(ObjectId id)
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select
public List<T> select(ObjectContext context)
Description copied from interface:Select
Selects objects using provided context.Essentially the inversion of "ObjectContext.select(Select)".
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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)".
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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 interfaceSelect<T>
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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)".
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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 useSelect.iterate(ObjectContext, ResultIteratorCallback)
as an alternative.Essentially the inversion of "ObjectContext.iterator(Select)".
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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 interfaceSelect<T>
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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);
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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);
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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);
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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);
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getCacheStrategy
public QueryCacheStrategy getCacheStrategy()
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cacheStrategy
public SelectById<T> cacheStrategy(QueryCacheStrategy strategy)
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cacheStrategy
public SelectById<T> cacheStrategy(QueryCacheStrategy strategy, String cacheGroup)
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getCacheGroup
public String getCacheGroup()
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cacheGroup
public SelectById<T> cacheGroup(String cacheGroup)
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isFetchingDataRows
public boolean isFetchingDataRows()
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prefetch
public SelectById<T> prefetch(PrefetchTreeNode prefetch)
Merges prefetch into the query prefetch tree.- Returns:
- this object
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prefetch
public SelectById<T> prefetch(String path, int semantics)
Merges a prefetch path with specified semantics into the query prefetch tree.- Returns:
- this object
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getPrefetches
public PrefetchTreeNode getPrefetches()
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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 classIndirectQuery
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resolveEntity
protected ObjEntity resolveEntity(EntityResolver resolver)
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