io.katharsis.repository

Interface RelationshipRepository<T,T_ID extends Serializable,D,D_ID extends Serializable>

Type Parameters:

T - source class type

T_ID - T class id type

D - target class type

D_ID - D class id type

public interface RelationshipRepository<T,T_ID extends Serializable,D,D_ID extends Serializable>

Base unidirectional repository responsible for operations on relations. All of the methods in this interface have fieldName field as last parameter. It solves a problem of many relationships between the same resources.

There are two methods that are used for To-One relationships:

• setRelation
• findOneTarget

There are two methods that are used for To-One relationships:

• setRelations
• addRelation
• removeRelation
• findManyTargets

The reason why there is more than one method for To-Many relationships manipulation is to prevent race condition situations in which a field could be changed concurrently by another request.

Field Summary

Fields

Modifier and Type	Field and Description
static int	TARGET_TYPE_GENERIC_PARAMETER_IDX

Method Summary

Modifier and Type	Method and Description
void	addRelations(T source, Iterable<D_ID> targetIds, String fieldName) Add a relation to a field.
Iterable<D>	findManyTargets(T_ID sourceId, String fieldName, RequestParams requestParams) Find a relation's target identifiers.
D	findOneTarget(T_ID sourceId, String fieldName, RequestParams requestParams) Find a relation's target identifier.
void	removeRelations(T source, Iterable<D_ID> targetIds, String fieldName) Removes a relationship from a set of relationships.
void	setRelation(T source, D_ID targetId, String fieldName) Set a relation defined by a field.
void	setRelations(T source, Iterable<D_ID> targetIds, String fieldName) Set a relation defined by a field.

Field Detail

TARGET_TYPE_GENERIC_PARAMETER_IDX

static final int TARGET_TYPE_GENERIC_PARAMETER_IDX

See Also:

Constant Field Values

Method Detail

setRelation

void setRelation(T source,
                 D_ID targetId,
                 String fieldName)

Set a relation defined by a field. targetId parameter can be either in a form of an object or null value, which means that if there's a relation, it should be removed. It is used only for To-One relationship.

Parameters:

source - instance of a source class

targetId - id of a target resource

fieldName - name of target's filed

setRelations

void setRelations(T source,
                  Iterable<D_ID> targetIds,
                  String fieldName)

Set a relation defined by a field. TargetIds parameter can be either in a form of an object or null value, which means that if there's a relation, it should be removed. It is used only for To-Many relationship.

Parameters:

source - instance of a source class

targetIds - ids of a target resource

fieldName - name of target's filed

addRelations

void addRelations(T source,
                  Iterable<D_ID> targetIds,
                  String fieldName)

Add a relation to a field. It is used only for To-Many relationship, that is if this method is called, a new relationship should be added to the set of the relationships.

Parameters:

source - instance of source class

targetIds - ids of the target resource

fieldName - name of target's field

removeRelations

void removeRelations(T source,
                     Iterable<D_ID> targetIds,
                     String fieldName)

Removes a relationship from a set of relationships. It is used only for To-Many relationship.

Parameters:

source - instance of source class

targetIds - ids of the target resource

fieldName - name of target's field

findOneTarget

D findOneTarget(T_ID sourceId,
                String fieldName,
                RequestParams requestParams)

Find a relation's target identifier. It is used only for To-One relationship.

Parameters:

sourceId - an identifier of a source

fieldName - name of target's filed

requestParams - parameters sent along with the request

Returns:

an identifier of a target of a relation

findManyTargets

Iterable<D> findManyTargets(T_ID sourceId,
                            String fieldName,
                            RequestParams requestParams)

Find a relation's target identifiers. It is used only for To-Many relationship.

Parameters:

sourceId - an identifier of a source

fieldName - name of target's filed

requestParams - parameters sent along with the request

Returns:

identifiers of targets of a relation