org.apache.cayenne

Interface ObjectContext

All Superinterfaces:

DataChannel, Serializable

All Known Implementing Classes:

BaseContext, CayenneContext, DataContext

public interface ObjectContext
extends DataChannel, Serializable

A Cayenne object facade to a persistent store. Instances of ObjectContext are used in the application code to access Cayenne persistence features.

Since:

1.2

Field Summary

Fields inherited from interface org.apache.cayenne.DataChannel

FLUSH_CASCADE_SYNC, FLUSH_NOCASCADE_SYNC, GRAPH_CHANGED_SUBJECT, GRAPH_FLUSHED_SUBJECT, GRAPH_ROLLEDBACK_SUBJECT, ROLLBACK_CASCADE_SYNC

Method Summary

Methods

Modifier and Type	Method and Description
void	commitChanges() Flushes all changes to objects in this context to the parent DataChannel, cascading flush operation all the way through the stack, ultimately saving data in the database.
void	commitChangesToParent() Flushes all changes to objects in this context to the parent DataChannel.
Collection<?>	deletedObjects() Returns a collection of objects that are registered with this ObjectContext and have a state PersistenceState.DELETED
void	deleteObject(Object object) Schedules deletion of a persistent object.
void	deleteObjects(Collection<?> objects) Schedules deletion of a collection of persistent objects.
<T> void	deleteObjects(T... objects) Schedules deletion of one or more persistent objects.
DataChannel	getChannel() Returns an DataChannel used by this context.
EntityResolver	getEntityResolver() Returns EntityResolver that stores all mapping information accessible by this ObjectContext.
GraphManager	getGraphManager() Returns GraphManager that manages object graph associated with this context.
Object	getUserProperty(String key) Returns a user-defined property previously set via 'setUserProperty'.
boolean	hasChanges() Returns true if there are any modified, deleted or new objects registered with this ObjectContext, false otherwise.
void	invalidateObjects(Collection<?> objects) Invalidates a Collection of persistent objects.
<T> void	invalidateObjects(T... objects) Invalidates one or more persistent objects.
<T> void	iterate(Select<T> query, ResultIteratorCallback<T> callback) Creates a ResultIterator based on the provided query and passes it to a callback for processing.
<T> ResultIterator<T>	iterator(Select<T> query) Creates a ResultIterator based on the provided query.
<T extends Persistent> T	localObject(T objectFromAnotherContext) Returns a local copy of 'objectFromAnotherContext' object.
Collection<?>	modifiedObjects() Returns a collection of objects that are registered with this ObjectContext and have a state PersistenceState.MODIFIED
<T> T	newObject(Class<T> persistentClass) Creates a new persistent object of a given class scheduled to be inserted to the database on next commit.
Collection<?>	newObjects() Returns a collection of objects that are registered with this ObjectContext and have a state PersistenceState.NEW
QueryResponse	performGenericQuery(Query query) Executes any kind of query providing the result in a form of QueryResponse.
List	performQuery(Query query) Executes a selecting query, returning a list of persistent objects or data rows.
void	prepareForAccess(Persistent object, String property, boolean lazyFaulting) A callback method that child Persistent objects are expected to call before accessing property values.
void	propertyChanged(Persistent object, String property, Object oldValue, Object newValue) A callback method that child Persistent objects are expected to call from inside the setter after modifying a value of a persistent property, including "simple" and "arc" properties.
void	registerNewObject(Object object) Registers a transient object with the context.
void	rollbackChanges() Resets all uncommitted changes made to the objects in this ObjectContext, cascading rollback operation all the way through the stack.
void	rollbackChangesLocally() Resets all uncommitted changes made to the objects in this ObjectContext.
<T> List<T>	select(Select<T> query) Executes a selecting query, returning a list of persistent objects or data rows.
<T> T	selectOne(Select<T> query) Executes a selecting query, returning either NULL if query matched no objects, or a single object.
void	setUserProperty(String key, Object value) Sets a user-defined property.
Collection<?>	uncommittedObjects() Returns a collection of MODIFIED, DELETED or NEW objects.

Methods inherited from interface org.apache.cayenne.DataChannel

getEventManager, onQuery, onSync

Method Detail

getEntityResolver

EntityResolver getEntityResolver()

Returns EntityResolver that stores all mapping information accessible by this ObjectContext.

Specified by:

getEntityResolver in interface DataChannel

newObjects

Collection<?> newObjects()

Returns a collection of objects that are registered with this ObjectContext and have a state PersistenceState.NEW

deletedObjects

Collection<?> deletedObjects()

Returns a collection of objects that are registered with this ObjectContext and have a state PersistenceState.DELETED

modifiedObjects

Collection<?> modifiedObjects()

Returns a collection of objects that are registered with this ObjectContext and have a state PersistenceState.MODIFIED

uncommittedObjects

Collection<?> uncommittedObjects()

Returns a collection of MODIFIED, DELETED or NEW objects.

localObject

<T extends Persistent> T localObject(T objectFromAnotherContext)

Returns a local copy of 'objectFromAnotherContext' object. "Local" means that the returned object is registered in this context. If the local object hasn't been previously cached in this context, a hollow object is created and returned to the caller. No DB query is performed to resolve an object.

Note that passing an object with a non-existing id, may later result in FaultFailureException on attempt to read returned object properties.

Since:

3.1

newObject

<T> T newObject(Class<T> persistentClass)

Creates a new persistent object of a given class scheduled to be inserted to the database on next commit.

registerNewObject

void registerNewObject(Object object)

Registers a transient object with the context. The difference with newObject(Class) is that a user creates an object herself, before attaching it to the context, instead of relying on Cayenne to do that.

Parameters:

object - new object that needs to be made persistent.

Since:

3.0

deleteObject

void deleteObject(Object object)
                  throws DeleteDenyException

Schedules deletion of a persistent object.

Throws:

DeleteDenyException - if a DeleteRule.DENY delete rule is applicable for object deletion.

deleteObjects

void deleteObjects(Collection<?> objects)
                   throws DeleteDenyException

Schedules deletion of a collection of persistent objects.

Throws:

DeleteDenyException - if a DeleteRule.DENY delete rule is applicable for object deletion.

deleteObjects

<T> void deleteObjects(T... objects)
                   throws DeleteDenyException

Schedules deletion of one or more persistent objects. Same as deleteObjects(Collection) only with a vararg argument list for easier deletion of individual objects.

Throws:

DeleteDenyException - if a DeleteRule.DENY delete rule is applicable for object deletion.

Since:

3.1

prepareForAccess

void prepareForAccess(Persistent object,
                    String property,
                    boolean lazyFaulting)

A callback method that child Persistent objects are expected to call before accessing property values. This callback allows ObjectContext to "inflate" unresolved objects on demand and also resolve properties that rely on lazy faulting.

Since:

3.0

propertyChanged

void propertyChanged(Persistent object,
                   String property,
                   Object oldValue,
                   Object newValue)

A callback method that child Persistent objects are expected to call from inside the setter after modifying a value of a persistent property, including "simple" and "arc" properties.

commitChanges

void commitChanges()

Flushes all changes to objects in this context to the parent DataChannel, cascading flush operation all the way through the stack, ultimately saving data in the database.

commitChangesToParent

void commitChangesToParent()

Flushes all changes to objects in this context to the parent DataChannel. Same as commitChanges(), but no cascading flush occurs.

rollbackChanges

void rollbackChanges()

Resets all uncommitted changes made to the objects in this ObjectContext, cascading rollback operation all the way through the stack.

rollbackChangesLocally

void rollbackChangesLocally()

Resets all uncommitted changes made to the objects in this ObjectContext. Same as rollbackChanges(), but rollback is local to this context and no cascading changes undoing occurs.

performQuery

List performQuery(Query query)

Executes a selecting query, returning a list of persistent objects or data rows.

select

<T> List<T> select(Select<T> query)

Executes a selecting query, returning a list of persistent objects or data rows.

Since:

4.0

selectOne

<T> T selectOne(Select<T> query)

Executes a selecting query, returning either NULL if query matched no objects, or a single object. If query matches more than one object, CayenneRuntimeException is thrown.

Since:

4.0

iterate

<T> void iterate(Select<T> query,
               ResultIteratorCallback<T> callback)

Creates a ResultIterator based on the provided query 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.

Since:

4.0

iterator

<T> ResultIterator<T> iterator(Select<T> query)

Creates a ResultIterator based on the provided query. 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 and close the ResultIterator explicitly. Or use iterate(Select, ResultIteratorCallback) as an alternative.

Since:

4.0

performGenericQuery

QueryResponse performGenericQuery(Query query)

Executes any kind of query providing the result in a form of QueryResponse.

getGraphManager

GraphManager getGraphManager()

Returns GraphManager that manages object graph associated with this context.

getChannel

DataChannel getChannel()

Returns an DataChannel used by this context.

hasChanges

boolean hasChanges()

Returns true if there are any modified, deleted or new objects registered with this ObjectContext, false otherwise.

Since:

3.0

invalidateObjects

void invalidateObjects(Collection<?> objects)

Invalidates a Collection of persistent objects. This operation only applies to the objects already committed to the database and does nothing to the NEW objects. It would remove each object's snapshot from caches and change object's state to HOLLOW. On the next access to this object, the object will be refetched.

invalidateObjects

<T> void invalidateObjects(T... objects)

Invalidates one or more persistent objects. Same as invalidateObjects(Collection) only with a vararg argument list for easier invalidation of individual objects. If no arguments are passed to this method, it does nothing.

Since:

3.1

getUserProperty

Object getUserProperty(String key)

Returns a user-defined property previously set via 'setUserProperty'. Concurrent access to properties does not require any special synchronization

Since:

3.0

setUserProperty

void setUserProperty(String key,
                   Object value)

Sets a user-defined property. Concurrent access to properties does not require any special synchronization

Since:

3.0