Package io.objectbox.relation

Class ToOne<TARGET>

  • All Implemented Interfaces:
    java.io.Serializable
    public class ToOne<TARGET>
extends java.lang.Object
implements java.io.Serializable
    Manages a to-one relation: resolves the target object, keeps the target Id in sync, etc. A to-relation is unidirectional: it points from the source entity to the target entity. The target is referenced by its ID, which is persisted in the source entity.

    If there is a ToMany relation linking back to this to-one relation (@Backlink), the ToMany object will not be notified/updated about persisted changes here. Call ToMany.reset() so it will update when next accessed.

    See Also:
    Serialized Form

    • Constructor Detail

      • ToOne

        public ToOne​(java.lang.Object sourceEntity,
             RelationInfo<?,​TARGET> relationInfo)
        In Java, the constructor call is generated by the ObjectBox plugin.
        Parameters:
        sourceEntity - The source entity that owns the to-one relation.
        relationInfo - Meta info as generated in the Entity_ (entity name plus underscore) classes.

    • Method Detail

      • getTarget

        public TARGET getTarget()
        Returns:
        The target entity of the to-one relation.

      • getTarget

        @Internal
public TARGET getTarget​(long targetId)
        If property backed, entities can pass the target ID to avoid reflection.

      • getCachedTarget

        public TARGET getCachedTarget()

      • isResolved

        public boolean isResolved()

      • isResolvedAndNotNull

        public boolean isResolvedAndNotNull()

      • isNull

        public boolean isNull()

      • setTargetId

        public void setTargetId​(long targetId)
        Sets or clears the target ID in the source entity. Pass 0 to clear.

        Put the source entity to persist changes. If the ID is not 0 creates a relation to the target entity with this ID, otherwise dissolves it.

        See Also:
        setTarget(TARGET)

      • setTarget

        public void setTarget​(@Nullable
                      TARGET target)
        Sets or clears the target entity and ID in the source entity. Pass null to clear.

        Put the source entity to persist changes. If the target entity was not put yet (its ID is 0), it will be stored when the source entity is put.

        See Also:
        setTargetId(long)

      • setAndPutTarget

        public void setAndPutTarget​(@Nullable
                            TARGET target)
        Sets or clears the target entity and ID in the source entity, then puts the source entity to persist changes. Pass null to clear.

        If the target entity was not put yet (its ID is 0), it will be put before the source entity.

      • setAndPutTargetAlways

        public void setAndPutTargetAlways​(@Nullable
                                  TARGET target)
        Sets or clears the target entity and ID in the source entity, then puts the target (if not null) and source entity to persist changes. Pass null to clear.

        When clearing the target entity, this does not remove it from its box. This only dissolves the relation.

      • getTargetId

        public long getTargetId()

      • internalRequiresPutTarget

        @Internal
public boolean internalRequiresPutTarget()

      • internalPutTarget

        @Internal
public void internalPutTarget​(io.objectbox.Cursor<TARGET> targetCursor)

      • equals

        public boolean equals​(java.lang.Object obj)
        Overrides:
        equals in class java.lang.Object

      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class java.lang.Object