org.dspace.core

Class AbstractHibernateDAO<T>

java.lang.Object

org.dspace.core.AbstractHibernateDAO<T>

Type Parameters:

T - class type

All Implemented Interfaces:

GenericDAO<T>

Direct Known Subclasses:

AbstractHibernateDSODAO, BasicWorkflowItemDAOImpl, BitstreamFormatDAOImpl, ChecksumHistoryDAOImpl, ChecksumResultDAOImpl, ClaimedTaskDAOImpl, CollectionRoleDAOImpl, DOIDAOImpl, EntityTypeDAOImpl, Group2GroupCacheDAOImpl, HandleDAOImpl, HarvestedCollectionDAOImpl, HarvestedItemDAOImpl, InProgressUserDAOImpl, MetadataFieldDAOImpl, MetadataSchemaDAOImpl, MetadataValueDAOImpl, MostRecentChecksumDAOImpl, PoolTaskDAOImpl, RegistrationDataDAOImpl, RelationshipDAOImpl, RelationshipTypeDAOImpl, RequestItemDAOImpl, ResourcePolicyDAOImpl, SiteDAOImpl, SubscriptionDAOImpl, TaskListItemDAOImpl, VersionDAOImpl, VersionHistoryDAOImpl, WebAppDAOImpl, WorkflowItemRoleDAOImpl, WorkspaceItemDAOImpl, XmlWorkflowItemDAOImpl

public abstract class AbstractHibernateDAO<T>
extends Object
implements GenericDAO<T>

Hibernate implementation for generic DAO interface. Also includes additional Hibernate calls that are commonly used. Each DAO should extend this class to prevent code duplication.

Author:

kevinvandevelde at atmire.com

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractHibernateDAO()

Method Summary

Modifier and Type	Method and Description
int	count(Context context, javax.persistence.criteria.CriteriaQuery criteriaQuery, javax.persistence.criteria.CriteriaBuilder criteriaBuilder, javax.persistence.criteria.Root<T> root) This method will return the amount of results that would be generated for this CriteriaQuery as an integer
int	count(javax.persistence.Query query) This method will return the count of items for this query as an integer This query needs to already be in a formate that'll return one record that contains the amount
long	countLong(Context context, javax.persistence.criteria.CriteriaQuery criteriaQuery, javax.persistence.criteria.CriteriaBuilder criteriaBuilder, javax.persistence.criteria.Root<T> root) This method will return the count of items for this query as a long
T	create(Context context, T t) Create a new instance of this type in the database.
javax.persistence.Query	createQuery(Context context, String query) Create a parsed query from a query expression.
void	delete(Context context, T t) Remove an instance from the database.
List<T>	executeCriteriaQuery(Context context, javax.persistence.criteria.CriteriaQuery<T> criteriaQuery, boolean cacheable, int maxResults, int offset) This method will return a list of objects to be returned that match the given criteriaQuery and parameters.
List<T>	findAll(Context context, Class<T> clazz) Fetch all persisted instances of a given object type.
T	findByID(Context context, Class clazz, int id) Fetch the entity identified by its legacy database identifier.
T	findByID(Context context, Class clazz, UUID id) Fetch the entity identified by its UUID primary key.
List<T>	findByX(Context context, Class clazz, Map<String,Object> equals, boolean cacheable, int maxResults, int offset) This method can be used to construct a query for which there needs to be a bunch of equal properties These properties can be passed along in the equals hashmap
List<T>	findMany(Context context, javax.persistence.Query query) Execute a JPA Criteria query and return a collection of results.
List<T>	findMany(Context context, String query) Execute a JPQL query and return a collection of results.
T	findUnique(Context context, String query) Execute a JPQL query returning a unique result.
javax.persistence.criteria.CriteriaBuilder	getCriteriaBuilder(Context context) This method should always be used in order to retrieve a CriteriaBuilder for the given context
javax.persistence.criteria.CriteriaQuery<T>	getCriteriaQuery(javax.persistence.criteria.CriteriaBuilder criteriaBuilder, Class<T> clazz) This method should always be used in order to retrieve the CriteriaQuery in order to start creating a query that has to be executed
protected org.hibernate.Session	getHibernateSession(Context context) The Session used to manipulate entities of this type.
Iterator<T>	iterate(javax.persistence.Query query) This method will return an Iterator for the given Query
List<T>	list(Context context, javax.persistence.criteria.CriteriaQuery criteriaQuery, boolean cacheable, Class<T> clazz, int maxResults, int offset) This method will return a list with unique results, no duplicates, made by the given CriteriaQuery and parameters
List<T>	list(Context context, javax.persistence.criteria.CriteriaQuery criteriaQuery, boolean cacheable, Class<T> clazz, int maxResults, int offset, boolean distinct) This method will return a list of results for the given CriteriaQuery and parameters
List<T>	list(javax.persistence.Query query) This method will be used to return a list of results for the given query
void	save(Context context, T t) Persist this instance in the database.
T	singleResult(Context context, javax.persistence.criteria.CriteriaQuery criteriaQuery) Retrieve a single result from the query.
T	singleResult(javax.persistence.Query query) This method will return the first result from the given query or null if no results were found
T	uniqueResult(Context context, javax.persistence.criteria.CriteriaQuery criteriaQuery, boolean cacheable, Class<T> clazz, int maxResults, int offset) Retrieve a unique result from the query.
T	uniqueResult(javax.persistence.Query query) This method will return a singular result for the given query

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractHibernateDAO

protected AbstractHibernateDAO()

Method Detail

create

public T create(Context context,
                T t)
         throws SQLException

Description copied from interface: GenericDAO

Create a new instance of this type in the database.

Specified by:

create in interface GenericDAO<T>

Parameters:

context - current DSpace context.

t - type to be created.

Returns:

entity tracking the created instance.

Throws:

SQLException

save

public void save(Context context,
                 T t)
          throws SQLException

Description copied from interface: GenericDAO

Persist this instance in the database.

Specified by:

save in interface GenericDAO<T>

Parameters:

context - current DSpace context.

t - type created here.

Throws:

SQLException - passed through.

getHibernateSession

protected org.hibernate.Session getHibernateSession(Context context)
                                             throws SQLException

The Session used to manipulate entities of this type.

Parameters:

context - current DSpace context.

Returns:

the current Session.

Throws:

SQLException

delete

public void delete(Context context,
                   T t)
            throws SQLException

Description copied from interface: GenericDAO

Remove an instance from the database.

Specified by:

delete in interface GenericDAO<T>

Parameters:

context - current DSpace context.

t - type of the instance to be removed.

Throws:

SQLException - passed through.

findAll

public List<T> findAll(Context context,
                       Class<T> clazz)
                throws SQLException

Description copied from interface: GenericDAO

Fetch all persisted instances of a given object type.

Specified by:

findAll in interface GenericDAO<T>

Parameters:

context - The relevant DSpace Context.

clazz - the desired type.

Returns:

list of DAOs of the same type as clazz

Throws:

SQLException - if database error

findUnique

public T findUnique(Context context,
                    String query)
             throws SQLException

Description copied from interface: GenericDAO

Execute a JPQL query returning a unique result.

Specified by:

findUnique in interface GenericDAO<T>

Parameters:

context - The relevant DSpace Context.

query - JPQL query string

Returns:

a DAO specified by the query string

Throws:

SQLException - if database error

findByID

public T findByID(Context context,
                  Class clazz,
                  UUID id)
           throws SQLException

Description copied from interface: GenericDAO

Fetch the entity identified by its UUID primary key.

Specified by:

findByID in interface GenericDAO<T>

Parameters:

context - current DSpace context.

clazz - class of entity to be found.

id - primary key of the database record.

Returns:

the found entity.

Throws:

SQLException

findByID

public T findByID(Context context,
                  Class clazz,
                  int id)
           throws SQLException

Description copied from interface: GenericDAO

Fetch the entity identified by its legacy database identifier.

Specified by:

findByID in interface GenericDAO<T>

Parameters:

context - current DSpace context.

clazz - class of entity to be found.

id - legacy database record ID.

Returns:

the found entity.

Throws:

SQLException - passed through.

findMany

public List<T> findMany(Context context,
                        String query)
                 throws SQLException

Description copied from interface: GenericDAO

Execute a JPQL query and return a collection of results.

Specified by:

findMany in interface GenericDAO<T>

Parameters:

context - The relevant DSpace Context.

query - JPQL query string

Returns:

list of DAOs specified by the query string

Throws:

SQLException - if database error

findMany

public List<T> findMany(Context context,
                        javax.persistence.Query query)
                 throws SQLException

Execute a JPA Criteria query and return a collection of results.

Parameters:

context - The relevant DSpace Context.

query - JPQL query string

Returns:

list of DAOs specified by the query string

Throws:

SQLException - if database error

createQuery

public javax.persistence.Query createQuery(Context context,
                                           String query)
                                    throws SQLException

Create a parsed query from a query expression.

Parameters:

context - current DSpace context.

query - textual form of the query.

Returns:

parsed form of the query.

Throws:

SQLException

list

public List<T> list(Context context,
                    javax.persistence.criteria.CriteriaQuery criteriaQuery,
                    boolean cacheable,
                    Class<T> clazz,
                    int maxResults,
                    int offset)
             throws SQLException

This method will return a list with unique results, no duplicates, made by the given CriteriaQuery and parameters

Parameters:

context - The standard DSpace context object

criteriaQuery - The CriteriaQuery for which this list will be retrieved

cacheable - Whether or not this query should be cacheable

clazz - The clazz for which this CriteriaQuery will be executed on

maxResults - The maxmimum amount of results that will be returned for this CriteriaQuery

offset - The offset to be used for the CriteriaQuery

Returns:

A list of distinct results as depicted by the CriteriaQuery and parameters

Throws:

SQLException

list

public List<T> list(Context context,
                    javax.persistence.criteria.CriteriaQuery criteriaQuery,
                    boolean cacheable,
                    Class<T> clazz,
                    int maxResults,
                    int offset,
                    boolean distinct)
             throws SQLException

This method will return a list of results for the given CriteriaQuery and parameters

Parameters:

context - The standard DSpace context object

criteriaQuery - The CriteriaQuery to be used to find the list of results

cacheable - A boolean value indicating whether this query should be cached or not

clazz - The class on which the CriteriaQuery will search

maxResults - The maximum amount of results to be returned

offset - The offset to be used for the CriteriaQuery

distinct - A boolean value indicating whether this list should be distinct or not

Returns:

A list of results determined by the CriteriaQuery and parameters

Throws:

SQLException

list

public List<T> list(javax.persistence.Query query)

This method will be used to return a list of results for the given query

Parameters:

query - The query for which the resulting list will be returned

Returns:

The list of results for the given query

uniqueResult

public T uniqueResult(Context context,
                      javax.persistence.criteria.CriteriaQuery criteriaQuery,
                      boolean cacheable,
                      Class<T> clazz,
                      int maxResults,
                      int offset)
               throws SQLException

Retrieve a unique result from the query. If multiple results CAN be retrieved an exception will be thrown, so only use when the criteria state uniqueness in the database.

Parameters:

criteriaQuery - JPA criteria

Returns:

a DAO specified by the criteria

Throws:

SQLException

singleResult

public T singleResult(Context context,
                      javax.persistence.criteria.CriteriaQuery criteriaQuery)
               throws SQLException

Retrieve a single result from the query. Best used if you expect a single result, but this isn't enforced on the database.

Parameters:

criteriaQuery - JPA criteria

Returns:

a DAO specified by the criteria

Throws:

SQLException

singleResult

public T singleResult(javax.persistence.Query query)

This method will return the first result from the given query or null if no results were found

Parameters:

query - The query that is to be executed

Returns:

One result from the given query or null if none was found

uniqueResult

public T uniqueResult(javax.persistence.Query query)

This method will return a singular result for the given query

Parameters:

query - The query for which a single result will be given

Returns:

The single result for this query

iterate

public Iterator<T> iterate(javax.persistence.Query query)

This method will return an Iterator for the given Query

Parameters:

query - The query for which an Iterator will be made

Returns:

The Iterator for the results of this query

count

public int count(Context context,
                 javax.persistence.criteria.CriteriaQuery criteriaQuery,
                 javax.persistence.criteria.CriteriaBuilder criteriaBuilder,
                 javax.persistence.criteria.Root<T> root)
          throws SQLException

This method will return the amount of results that would be generated for this CriteriaQuery as an integer

Parameters:

context - The standard DSpace Context object

criteriaQuery - The CriteriaQuery for which this result will be retrieved

criteriaBuilder - The CriteriaBuilder that accompagnies the CriteriaQuery

root - The root that'll determine on which class object we need to calculate the result

Returns:

The amount of results that would be found by this CriteriaQuery as an integer value

Throws:

SQLException

count

public int count(javax.persistence.Query query)

This method will return the count of items for this query as an integer This query needs to already be in a formate that'll return one record that contains the amount

Parameters:

query - The query for which the amount of results will be returned.

Returns:

The amount of results

countLong

public long countLong(Context context,
                      javax.persistence.criteria.CriteriaQuery criteriaQuery,
                      javax.persistence.criteria.CriteriaBuilder criteriaBuilder,
                      javax.persistence.criteria.Root<T> root)
               throws SQLException

This method will return the count of items for this query as a long

Parameters:

context - The standard DSpace Context object

criteriaQuery - The CriteriaQuery for which the amount of results will be retrieved

criteriaBuilder - The CriteriaBuilder that goes along with this CriteriaQuery

root - The root created for a DSpace class on which this query will search

Returns:

A long value that depicts the amount of results this query has found

Throws:

SQLException

getCriteriaQuery

public javax.persistence.criteria.CriteriaQuery<T> getCriteriaQuery(javax.persistence.criteria.CriteriaBuilder criteriaBuilder,
                                                                    Class<T> clazz)

This method should always be used in order to retrieve the CriteriaQuery in order to start creating a query that has to be executed

Parameters:

criteriaBuilder - The CriteriaBuilder for which this CriteriaQuery will be constructed

clazz - The class that this CriteriaQuery will be constructed for

Returns:

A CriteriaQuery on which a query can be built

getCriteriaBuilder

public javax.persistence.criteria.CriteriaBuilder getCriteriaBuilder(Context context)
                                                              throws SQLException

This method should always be used in order to retrieve a CriteriaBuilder for the given context

Parameters:

context - The standard DSpace Context class for which a CriteriaBuilder will be made

Returns:

A CriteriaBuilder that can be used to create the query

Throws:

SQLException

executeCriteriaQuery

public List<T> executeCriteriaQuery(Context context,
                                    javax.persistence.criteria.CriteriaQuery<T> criteriaQuery,
                                    boolean cacheable,
                                    int maxResults,
                                    int offset)
                             throws SQLException

This method will return a list of objects to be returned that match the given criteriaQuery and parameters. The maxResults and offSet can be circumvented by entering the value -1 for them.

Parameters:

context - The standard context DSpace object

criteriaQuery - The CriteriaQuery that will be used for executing the query

cacheable - Whether or not this query is able to be cached

maxResults - The maximum amount of results that this query will return This can be circumvented by passing along -1 as the value

offset - The offset to be used in this query This can be circumvented by passing along -1 as the value

Returns:

This will return a list of objects that conform to the made query

Throws:

SQLException

findByX

public List<T> findByX(Context context,
                       Class clazz,
                       Map<String,Object> equals,
                       boolean cacheable,
                       int maxResults,
                       int offset)
                throws SQLException

This method can be used to construct a query for which there needs to be a bunch of equal properties These properties can be passed along in the equals hashmap

Parameters:

context - The standard DSpace context object

clazz - The class on which the criteriaQuery will be built

equals - A hashmap that can be used to store the String representation of the column and the value that should match that in the DB

cacheable - A boolean indicating whether this query should be cacheable or not

maxResults - The max amount of results to be returned by this query

offset - The offset to be used in this query

Returns:

Will return a list of objects that correspond with the constructed query and parameters

Throws:

SQLException