li.strolch.persistence.api

Interface StrolchDao<T extends StrolchRootElement>

Type Parameters:

T - the object instance being queried from the underlying persistence layer

All Known Subinterfaces:

ActivityDao, OrderDao, ResourceDao

All Known Implementing Classes:

InMemoryActivityDao, InMemoryDao, InMemoryOrderDao, InMemoryResourceDao

public interface StrolchDao<T extends StrolchRootElement>

This data access object is used to access StrolchRootElement from the underlying persistence layer. Objects in Strolch are always referenced by a type and an ID. The type is a categorisation/grouping of the objects, while the ID is a unique identifier of the object. The ID must be unique, even for multiple groups.

The DAO must support versioning. i.e. if versioning is enabled, then if an object is updated or removed, the existing version is not modified, but a new version is persisted so that rollbacks can be done

Author:

Robert von Burg

Method Summary

Modifier and Type	Method and Description
void	flush() Causes the DAO to flush any actions which have not yet been sent to the underlying persistence layer
boolean	hasElement(String type, String id) Returns true if an element exists with the given type and id in the underlying persistence layer
List<T>	queryAll() Queries and returns all elements regardless of type
List<T>	queryAll(String type) Queries and returns all elements of the given type
T	queryBy(String type, String id) Queries the latest version of the element with the given type and ID
T	queryBy(String type, String id, int version) Queries a specific version of the element with the given type and ID.
Set<String>	queryKeySet() Queries the set of IDs for all elements, regardless of types from the underlying persistence layer.
Set<String>	queryKeySet(String type) Queries the set of IDs for the elements with the given type
long	querySize() Returns the number of elements in the underlying persistence layer, regardless of type
long	querySize(String type) Returns the number of elements in the underlying persistence layer for the given type
Set<String>	queryTypes() Queries the current list of types from the underlying persistence layer
List<T>	queryVersionsFor(String type, String id) Queries and returns all the versions of the element with the given type and ID
long	queryVersionsSizeFor(String type, String id) Queries and returns the number of versions for the element with the given type and ID
void	remove(T element) Removes the given element from the underlying persistence layer
long	removeAll() Removes all elements regardless of type from the underlying persistence layer
void	removeAll(List<T> elements) Removes the given elements from the underlying persistence layer
long	removeAllBy(String type) Removes all elements of the given type from the underlying persistence layer
void	removeVersion(T element) Removes the given version of the given element from the underlying persistence layer.
void	save(T element) Persists the given element.
void	saveAll(List<T> elements) Persists the given list of elements.
void	update(T element) Updates the given element.
void	updateAll(List<T> elements) Updates the given list of elements.

Method Detail

queryKeySet

Set<String> queryKeySet()

Queries the set of IDs for all elements, regardless of types from the underlying persistence layer.

Returns:

the set of IDs for all elements

hasElement

boolean hasElement(String type,
                   String id)

Returns true if an element exists with the given type and id in the underlying persistence layer

Parameters:

type - the type of elements

id - the id of the element to return

Returns:

true if an element exists with the given type and id

querySize

long querySize()

Returns the number of elements in the underlying persistence layer, regardless of type

Returns:

the number of elements in the underlying persistence layer

querySize

long querySize(String type)

Returns the number of elements in the underlying persistence layer for the given type

Returns:

the number of elements in the underlying persistence layer for the given type

queryKeySet

Set<String> queryKeySet(String type)

Queries the set of IDs for the elements with the given type

Returns:

the set of IDs for the elements with the given type

queryTypes

Set<String> queryTypes()

Queries the current list of types from the underlying persistence layer

Returns:

the list of types

queryBy

T queryBy(String type,
          String id)

Queries the latest version of the element with the given type and ID

Parameters:

type - the type of the element to be queried

id - the id of the element to be queried

Returns:

the element with the given type and ID, or null if it does not exist

queryBy

T queryBy(String type,
          String id,
          int version)

Queries a specific version of the element with the given type and ID.

Note: If you want to query the latest version, then use the method with out the version parameter

Parameters:

type - the type of the element to be queried

id - the id of the element to be queried

version - the version of the element to be returned

Returns:

the element with the given type and ID, or null if it does not exist

queryVersionsFor

List<T> queryVersionsFor(String type,
                         String id)

Queries and returns all the versions of the element with the given type and ID

Parameters:

type - the type of the element to be queried

id - the id of the element to be queried

Returns:

all the versions of the element with the given type and ID

queryVersionsSizeFor

long queryVersionsSizeFor(String type,
                          String id)

Queries and returns the number of versions for the element with the given type and ID

Parameters:

type - the type of the element to be queried

id - the id of the element to be queried

Returns:

the number of versions for the element with the given type and ID

queryAll

List<T> queryAll()

Queries and returns all elements regardless of type

Returns:

all elements regardless of type

queryAll

List<T> queryAll(String type)

Queries and returns all elements of the given type

Parameters:

type - the type of element to return

Returns:

all elements of the given type

save

void save(T element)
   throws StrolchPersistenceException

Persists the given element. The element must not yet exist

Parameters:

element - the element to be persisted

Throws:

StrolchPersistenceException - if the element already exists

saveAll

void saveAll(List<T> elements)
      throws StrolchPersistenceException

Persists the given list of elements. None of the elements may already exists

Parameters:

elements - the list of elements to be persisted

Throws:

StrolchPersistenceException - if any of the elements already exist

update

void update(T element)
     throws StrolchPersistenceException

Updates the given element. The element must already exist

Parameters:

element - the element to be updated

Throws:

StrolchPersistenceException - if the element does not exist

updateAll

void updateAll(List<T> elements)
        throws StrolchPersistenceException

Updates the given list of elements. Each element must already exist

Parameters:

elements - the elements to be updated

Throws:

StrolchPersistenceException - if any of the elements do not exist

remove

void remove(T element)
     throws StrolchPersistenceException

Removes the given element from the underlying persistence layer

Note: This method deletes the given object including its versions! Do not call this method if you want to use versioning!

Parameters:

element - the element to be removed

Throws:

StrolchPersistenceException - if the element does not exist

removeAll

void removeAll(List<T> elements)
        throws StrolchPersistenceException

Removes the given elements from the underlying persistence layer

Note: This method deletes the given objects including their versions! Do not call this method if you want to use versioning!

Parameters:

elements - the elements to be removed

Throws:

StrolchPersistenceException - if any of the elements do not exist

removeAll

long removeAll()

Removes all elements regardless of type from the underlying persistence layer

Note: This method does not support versioning. This method completely removes all objects regardless of type and their versions!

Returns:

the number of elements removed

Throws:

StrolchPersistenceException

removeAllBy

long removeAllBy(String type)

Removes all elements of the given type from the underlying persistence layer

Note: This method does not support versioning. This method completely removes all objects of the given type and their versions!

Parameters:

type - the type of element to remove

Returns:

the number of elements removed

removeVersion

void removeVersion(T element)
            throws StrolchPersistenceException

Removes the given version of the given element from the underlying persistence layer. The version must be the latest version and thus always deletes the newest version. To delete multiple versions call this method multiple times. To remove it completely, call the remove(StrolchRootElement) method.

Note: This element given must be the current latest version!

Parameters:

element - the latest version of the element to be removed

Throws:

StrolchPersistenceException - if the element/version does not exist

flush

void flush()

Causes the DAO to flush any actions which have not yet been sent to the underlying persistence layer