Package io.objectbox.relation

Class ToMany<TARGET>

java.lang.Object
io.objectbox.relation.ToMany<TARGET>
Type Parameters:
TARGET - Object type (entity).
All Implemented Interfaces:
Serializable, Iterable<TARGET>, Collection<TARGET>, List<TARGET>
public class ToMany<TARGET> extends Object implements List<TARGET>, Serializable
A List representing a to-many relation. It tracks changes (adds and removes) that can be later applied (persisted) to the database. This happens either on Box.put(Object) of the source entity of this relation or using applyChangesToDb().

If this relation is a backlink from a ToOne relation, a DB sync will also update ToOne objects (but not vice versa).

ToMany is thread-safe by default (only if the default CopyOnWriteArrayList is used).

See Also:

  • Constructor Details

  • Method Details

    • setListFactory

      @Experimental public void setListFactory(ListFactory listFactory)
      Currently only used for non-persisted entities (id == 0).

    • setComparator

      @Experimental public void setComparator(Comparator<TARGET> comparator)
      Set an comparator to define the order of entities.

    • setRemoveFromTargetBox

      @Experimental public void setRemoveFromTargetBox(boolean removeFromTargetBox)
      On put, this also deletes removed entities from the target Box. Note: removed target entities won't cascade the delete.

    • getListFactory

      public ListFactory getListFactory()

    • add

      public boolean add(TARGET object)
      Adds the given entity to the list and tracks the addition so it can be later applied to the database (e.g. via Box.put(Object) of the entity owning the ToMany, or via applyChangesToDb()). Note that the given entity will remain unchanged at this point (e.g. to-ones are not updated).
      Specified by:
      add in interface Collection<TARGET>
      Specified by:
      add in interface List<TARGET>

    • add

      public void add(int location, TARGET object)
      See add(Object) for general comments.
      Specified by:
      add in interface List<TARGET>

    • addAll

      public boolean addAll(Collection<? extends TARGET> objects)
      See add(Object) for general comments.
      Specified by:
      addAll in interface Collection<TARGET>
      Specified by:
      addAll in interface List<TARGET>

    • addAll

      public boolean addAll(int index, Collection<? extends TARGET> objects)
      See add(Object) for general comments.
      Specified by:
      addAll in interface List<TARGET>

    • clear

      public void clear()
      Specified by:
      clear in interface Collection<TARGET>
      Specified by:
      clear in interface List<TARGET>

    • contains

      public boolean contains(Object object)
      Specified by:
      contains in interface Collection<TARGET>
      Specified by:
      contains in interface List<TARGET>

    • containsAll

      public boolean containsAll(Collection<?> collection)
      Specified by:
      containsAll in interface Collection<TARGET>
      Specified by:
      containsAll in interface List<TARGET>

    • get

      public TARGET get(int location)
      Specified by:
      get in interface List<TARGET>
      Returns:
      An object for the given ID, or null if the object was already removed from its box (and was not cached before).

    • indexOf

      public int indexOf(Object object)
      Specified by:
      indexOf in interface List<TARGET>

    • isEmpty

      public boolean isEmpty()
      Specified by:
      isEmpty in interface Collection<TARGET>
      Specified by:
      isEmpty in interface List<TARGET>

    • iterator

      @Nonnull public Iterator<TARGET> iterator()
      Specified by:
      iterator in interface Collection<TARGET>
      Specified by:
      iterator in interface Iterable<TARGET>
      Specified by:
      iterator in interface List<TARGET>

    • lastIndexOf

      public int lastIndexOf(Object object)
      Specified by:
      lastIndexOf in interface List<TARGET>

    • listIterator

      @Nonnull public ListIterator<TARGET> listIterator()
      Specified by:
      listIterator in interface List<TARGET>

    • listIterator

      @Nonnull public ListIterator<TARGET> listIterator(int location)
      The returned iterator does not track any potential calls to Iterator.remove(). Thus these removes will NOT be synced to the target Box.
      Specified by:
      listIterator in interface List<TARGET>

    • remove

      public TARGET remove(int location)
      Specified by:
      remove in interface List<TARGET>

    • remove

      public boolean remove(Object object)
      Specified by:
      remove in interface Collection<TARGET>
      Specified by:
      remove in interface List<TARGET>

    • removeById

      public TARGET removeById(long id)
      Removes an object by its entity ID.

    • removeAll

      public boolean removeAll(Collection<?> objects)
      Specified by:
      removeAll in interface Collection<TARGET>
      Specified by:
      removeAll in interface List<TARGET>

    • retainAll

      public boolean retainAll(Collection<?> objects)
      Specified by:
      retainAll in interface Collection<TARGET>
      Specified by:
      retainAll in interface List<TARGET>

    • set

      public TARGET set(int location, TARGET object)
      Specified by:
      set in interface List<TARGET>

    • size

      public int size()
      Specified by:
      size in interface Collection<TARGET>
      Specified by:
      size in interface List<TARGET>

    • subList

      @Nonnull public List<TARGET> subList(int start, int end)
      The returned sub list does not do any change tracking. Thus any modifications to the sublist won't be synced to the target Box.
      Specified by:
      subList in interface List<TARGET>

    • toArray

      @Nonnull public Object[] toArray()
      Specified by:
      toArray in interface Collection<TARGET>
      Specified by:
      toArray in interface List<TARGET>

    • toArray

      @Nonnull public <T> T[] toArray(T[] array)
      Specified by:
      toArray in interface Collection<TARGET>
      Specified by:
      toArray in interface List<TARGET>

    • reset

      public void reset()
      Resets the already loaded entities so they will be re-loaded on their next access. This allows to sync with non-tracked changes (outside of this ToMany object).

    • isResolved

      public boolean isResolved()

    • getAddCount

      public int getAddCount()

    • getRemoveCount

      public int getRemoveCount()

    • sortById

      public void sortById()
      Sorts the list by the "natural" ObjectBox order for to-many list (by entity ID). This will be the order when you get the entities fresh (e.g. initially or after calling reset()). Note that non persisted entities (ID is zero) will be put to the end as they are still to get an ID.

    • applyChangesToDb

      public void applyChangesToDb()
      Applies (persists) tracked changes (added and removed entities) to the target box and/or updates standalone relations. Note that this is done automatically when you put the source entity of this to-many relation. However, if only this to-many relation has changed, it is more efficient to call this method.
      Throws:
      IllegalStateException - If the source entity of this to-many relation was not previously persisted

    • hasA

      @Beta public boolean hasA(QueryFilter<TARGET> filter)
      Returns true if at least one of the entities matches the given filter.

      For use with QueryBuilder.filter(QueryFilter) inside a QueryFilter to check to-many relation entities.

    • hasAll

      @Beta public boolean hasAll(QueryFilter<TARGET> filter)
      Returns true if all of the entities match the given filter. Returns false if the list is empty.

      For use with QueryBuilder.filter(QueryFilter) inside a QueryFilter to check to-many relation entities.

    • getById

      @Beta public TARGET getById(long id)
      Gets an object by its entity ID.

    • indexOfId

      @Beta public int indexOfId(long id)
      Gets the index of the object with the given entity ID.

    • hasPendingDbChanges

      public boolean hasPendingDbChanges()
      Returns true if there are pending changes for the DB. Changes will be automatically persisted once the owning entity is put, or an explicit call to applyChangesToDb() is made.

    • internalCheckApplyToDbRequired

      @Internal public boolean internalCheckApplyToDbRequired()
      For internal use only; do not use in your app. Called after relation source entity is put (so we have its ID). Prepares data for internalApplyToDb(Cursor, Cursor)

    • internalApplyToDb

      @Internal public void internalApplyToDb(io.objectbox.Cursor<?> sourceCursor, io.objectbox.Cursor<TARGET> targetCursor)
      For internal use only; do not use in your app. Convention: internalCheckApplyToDbRequired() must be called before this call as it prepares .