io.spine.server.entity

Class Repository<I,E extends Entity<I,?>>

java.lang.Object

io.spine.server.entity.Repository<I,E>

All Implemented Interfaces:

io.spine.logging.Logging, Closeable, java.lang.AutoCloseable

Direct Known Subclasses:

AggregateRepository, RecordBasedRepository

public abstract class Repository<I,E extends Entity<I,?>>
extends java.lang.Object
implements Closeable, io.spine.logging.Logging

Abstract base class for repositories.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Repository() Creates the repository.

Method Summary

Modifier and Type	Method and Description
protected static <S extends java.lang.AutoCloseable> S	checkStorage(S storage) Ensures that the storage is not null.
void	close() Closes the repository by closing the underlying storage.
protected BoundedContext	context() Obtains the BoundedContext to which this repository belongs.
abstract E	create(I id) Create a new entity instance with its default state.
protected abstract Storage<I,?,?>	createStorage() Creates the storage for this repository.
java.lang.Class<E>	entityClass() Returns the class of entities managed by this repository.
io.spine.type.TypeUrl	entityStateType() Obtains the TypeUrl for the state objects wrapped by entities managed by this repository.
EventFilter	eventFilter() Creates an EventFilter for this repository.
abstract java.util.Optional<E>	find(I id) Finds an entity with the passed ID.
protected boolean	hasContext() Verifies whether the repository is registered with a BoundedContext.
java.lang.Class<I>	idClass() Returns the class of IDs used by this repository.
java.util.Iterator<I>	index() Returns an iterator over the identifiers of all the entities managed by this repository.
boolean	isOpen() Verifies if the repository is open.
boolean	isRegistered() Tells if the repository is registered in a BoundedContext.
java.util.Iterator<E>	iterator(java.util.function.Predicate<E> filter) Returns an iterator over the entities managed by the repository that match the passed filter.
void	onRegistered() The callback is invoked by a BoundedContext when adding the repository.
protected void	open() Initializes the storage of the repository.
protected Storage<I,?,?>	storage() Returns the storage assigned to this repository.
boolean	storageAssigned() Returns true if the storage is assigned, false otherwise.
protected abstract void	store(E obj) Stores the passed object.

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.spine.server.Closeable

checkOpen

Methods inherited from interface io.spine.logging.Logging

_config, _debug, _error, _fine, _finer, _finest, _info, _severe, _trace, _warn, debugLevel, errorLevel, logger, loggerFor

Constructor Detail

Repository

protected Repository()

Creates the repository.

Method Detail

create

public abstract E create(I id)

Create a new entity instance with its default state.

Parameters:

id - the id of the entity

Returns:

new entity instance

store

protected abstract void store(E obj)

Stores the passed object.

Note: The storage must be assigned before calling this method.

Parameters:

obj - an instance to store

find

public abstract java.util.Optional<E> find(I id)

Finds an entity with the passed ID.

Parameters:

id - the ID of the entity to load

Returns:

the entity or Optional.empty() if there's no entity with such ID

iterator

public java.util.Iterator<E> iterator(java.util.function.Predicate<E> filter)

Returns an iterator over the entities managed by the repository that match the passed filter.

The returned iterator does not support removal.

Iteration through entities is performed by loading them one by one.

index

public java.util.Iterator<I> index()

Returns an iterator over the identifiers of all the entities managed by this repository.

idClass

public final java.lang.Class<I> idClass()

Returns the class of IDs used by this repository.

entityClass

public final java.lang.Class<E> entityClass()

Returns the class of entities managed by this repository.

entityStateType

public final io.spine.type.TypeUrl entityStateType()

Obtains the TypeUrl for the state objects wrapped by entities managed by this repository.

isRegistered

public boolean isRegistered()

Tells if the repository is registered in a BoundedContext.

hasContext

protected final boolean hasContext()

Verifies whether the repository is registered with a BoundedContext.

context

protected final BoundedContext context()

Obtains the BoundedContext to which this repository belongs.

Returns:

parent BoundedContext

Throws:

java.lang.IllegalStateException - if the repository has no context assigned

onRegistered

@OverridingMethodsMustInvokeSuper
public void onRegistered()

The callback is invoked by a BoundedContext when adding the repository.

open

protected final void open()

Initializes the storage of the repository.

storage

protected final Storage<I,?,?> storage()

Returns the storage assigned to this repository.

To verify if the storage is assigned, use Repository.storageAssigned().

Throws:

java.lang.IllegalStateException - if the storage is not assigned

storageAssigned

public final boolean storageAssigned()

Returns true if the storage is assigned, false otherwise.

checkStorage

protected static <S extends java.lang.AutoCloseable> S checkStorage(S storage)

Ensures that the storage is not null.

Returns:

passed value if it's not not null

Throws:

java.lang.IllegalStateException - if the passed instance is null

createStorage

protected abstract Storage<I,?,?> createStorage()

Creates the storage for this repository.

Default implementations use Repository.defaultStorageFactory() invoking its method which creates a storage compatible with the repository.

Overwrite this method for creating a custom implementation of Storage.

Returns:

the created storage instance

close

@OverridingMethodsMustInvokeSuper
public void close()

Closes the repository by closing the underlying storage.

The reference to the storage becomes null after this call.

Specified by:

close in interface java.lang.AutoCloseable

isOpen

public final boolean isOpen()

Verifies if the repository is open.

Specified by:

isOpen in interface Closeable

eventFilter

@SPI
 @Pure
public EventFilter eventFilter()

Creates an EventFilter for this repository.

All the events posted by this repository, domain, and system are first passed through this filter.

By default, the filter allows all the events to be posted. For entities which do not allow state subscription, the EntityStateChanged event is filtered out. Override this method to change this behaviour.

Returns:

an EventFilter to apply to all posted events

Implementation Note:

This method may be called many times for a single repository. It is reasonable that it does not re-initialize the filter each time. Also, it is necessary that the filter returned from this method is always (at least effectively) the same. See @Pure for the details on the expected behaviour.