io.realm

Class RealmList<E extends RealmModel>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractList<E>

io.realm.RealmList<E>

Type Parameters:

E - the class of objects in list.

All Implemented Interfaces:

OrderedRealmCollection<E>, RealmCollection<E>, java.lang.Iterable<E>, java.util.Collection<E>, java.util.List<E>

public final class RealmList<E extends RealmModel>
extends java.util.AbstractList<E>
implements OrderedRealmCollection<E>

RealmList is used to model one-to-many relationships in a RealmObject. RealmList has two modes: A managed and non-managed mode. In managed mode all objects are persisted inside a Realm, in non-managed mode it works as a normal ArrayList.

Only Realm can create managed RealmLists. Managed RealmLists will automatically update the content whenever the underlying Realm is updated, and can only be accessed using the getter of a RealmObject.

Unmanaged RealmLists can be created by the user and can contain both managed and non-managed RealmObjects. This is useful when dealing with JSON deserializers like GSON or other frameworks that inject values into a class. Unmanaged elements in this list can be added to a Realm using the Realm.copyToRealm(Iterable) method.

RealmList can contain more elements than Integer.MAX_VALUE. In that case, you can access only first Integer.MAX_VALUE elements in it.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	REMOVE_OUTSIDE_TRANSACTION_ERROR

Constructor Summary

Constructors

Constructor and Description
RealmList() Creates a RealmList in non-managed mode, where the elements are not controlled by a Realm.
RealmList(E... objects) Creates a RealmList in non-managed mode with an initial list of elements.

Method Summary

Modifier and Type	Method and Description
boolean	add(E object) Adds the specified object at the end of this List.
void	add(int location, E object) Inserts the specified object into this List at the specified location.
double	average(java.lang.String fieldName) Returns the average of a given field.
void	clear() Removes all elements from this list, leaving it empty.
boolean	contains(java.lang.Object object) Returns true if the list contains the specified element when attached to a Realm.
boolean	deleteAllFromRealm() This deletes all objects in the collection from the underlying Realm as well as from the collection.
boolean	deleteFirstFromRealm() Deletes the first object from the Realm.
void	deleteFromRealm(int location) Deletes the object at the given index from the Realm.
boolean	deleteLastFromRealm() Deletes the last object from the Realm.
E	first() Gets the first object from the collection.
E	get(int location) Returns the element at the specified location in this list.
boolean	isLoaded() Checks if a collection has finished loading its data yet.
boolean	isValid() Checks if the RealmList is managed by Realm and contains valid data i.e., the Realm instance hasn't been closed.
java.util.Iterator<E>	iterator()
E	last() Gets the last object from the collection.
java.util.ListIterator<E>	listIterator()
java.util.ListIterator<E>	listIterator(int location)
boolean	load() Blocks the collection until all data are available.
java.lang.Number	max(java.lang.String fieldName) Finds the maximum value of a field.
java.util.Date	maxDate(java.lang.String fieldName) Finds the maximum date.
java.lang.Number	min(java.lang.String fieldName) Finds the minimum value of a field.
java.util.Date	minDate(java.lang.String fieldName) Finds the minimum date.
void	move(int oldPos, int newPos) Moves an object from one position to another, while maintaining a fixed sized list.
E	remove(int location) Removes the object at the specified location from this list.
boolean	remove(java.lang.Object object) Removes one instance of the specified object from this Collection if one is contained.
boolean	removeAll(java.util.Collection<?> collection) Removes all occurrences in this Collection of each object in the specified Collection.
E	set(int location, E object) Replaces the element at the specified location in this list with the specified object.
int	size() Returns the number of elements in this List.
RealmResults<E>	sort(java.lang.String fieldName) Sorts a collection based on the provided field in ascending order.
RealmResults<E>	sort(java.lang.String[] fieldNames, Sort[] sortOrders) Sorts a collection based on the provided fields and sort orders.
RealmResults<E>	sort(java.lang.String fieldName, Sort sortOrder) Sorts a collection based on the provided field and sort order.
RealmResults<E>	sort(java.lang.String fieldName1, Sort sortOrder1, java.lang.String fieldName2, Sort sortOrder2) Sorts a collection based on the provided fields and sort orders.
java.lang.Number	sum(java.lang.String fieldName) Calculates the sum of a given field.
java.lang.String	toString()
RealmQuery<E>	where() Returns a RealmQuery, which can be used to query for specific objects of this class.

Methods inherited from class java.util.AbstractList

addAll, equals, hashCode, indexOf, lastIndexOf, subList

Methods inherited from class java.util.AbstractCollection

addAll, containsAll, isEmpty, retainAll, toArray, toArray

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.List

addAll, addAll, containsAll, equals, hashCode, indexOf, isEmpty, lastIndexOf, replaceAll, retainAll, sort, spliterator, subList, toArray, toArray

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream

Methods inherited from interface java.lang.Iterable

forEach

Field Detail

REMOVE_OUTSIDE_TRANSACTION_ERROR

public static final java.lang.String REMOVE_OUTSIDE_TRANSACTION_ERROR

See Also:

Constant Field Values

Constructor Detail

RealmList

public RealmList()

Creates a RealmList in non-managed mode, where the elements are not controlled by a Realm. This effectively makes the RealmList function as a ArrayList and it is not possible to query the objects in this state.

Use Realm.copyToRealm(Iterable) to properly persist its elements in Realm.

RealmList

public RealmList(E... objects)

Creates a RealmList in non-managed mode with an initial list of elements. A RealmList in non-managed mode function as a ArrayList and it is not possible to query the objects in this state.

Use Realm.copyToRealm(Iterable) to properly persist all non-managed elements in Realm.

Parameters:

objects - initial objects in the list.

Method Detail

isValid

public boolean isValid()

Checks if the RealmList is managed by Realm and contains valid data i.e., the Realm instance hasn't been closed.

Specified by:

isValid in interface RealmCollection<E extends RealmModel>

Returns:

true if still valid to use, false otherwise or if it's an unmanaged list.

add

public void add(int location,
                E object)

Inserts the specified object into this List at the specified location. The object is inserted before any previous element at the specified location. If the location is equal to the size of this List, the object is added at the end.

1. Unmanaged RealmLists: It is possible to add both managed and unmanaged objects. If adding managed objects to an unmanaged RealmList they will not be copied to the Realm again if using Realm.copyToRealm(RealmModel) afterwards.
2. Managed RealmLists: It is possible to add unmanaged objects to a RealmList that is already managed. In that case the object will transparently be copied to Realm using Realm.copyToRealm(RealmModel) or Realm.copyToRealmOrUpdate(RealmModel) if it has a primary key.

Specified by:

add in interface java.util.List<E extends RealmModel>

Overrides:

add in class java.util.AbstractList<E extends RealmModel>

Parameters:

location - the index at which to insert.

object - the object to add.

Throws:

java.lang.IllegalStateException - if Realm instance has been closed or container object has been removed.

java.lang.IndexOutOfBoundsException - if location < 0 || location > size().

add

public boolean add(E object)

Adds the specified object at the end of this List.

1. Unmanaged RealmLists: It is possible to add both managed and unmanaged objects. If adding managed objects to an unmanaged RealmList they will not be copied to the Realm again if using Realm.copyToRealm(RealmModel) afterwards.
2. Managed RealmLists: It is possible to add unmanaged objects to a RealmList that is already managed. In that case the object will transparently be copied to Realm using Realm.copyToRealm(RealmModel) or Realm.copyToRealmOrUpdate(RealmModel) if it has a primary key.

Specified by:

add in interface java.util.Collection<E extends RealmModel>

Specified by:

add in interface java.util.List<E extends RealmModel>

Overrides:

add in class java.util.AbstractList<E extends RealmModel>

Parameters:

object - the object to add.

Returns:

always true.

Throws:

java.lang.IllegalStateException - if Realm instance has been closed or parent object has been removed.

set

public E set(int location,
             E object)

Replaces the element at the specified location in this list with the specified object.

1. Unmanaged RealmLists: It is possible to add both managed and unmanaged objects. If adding managed objects to an unmanaged RealmList they will not be copied to the Realm again if using Realm.copyToRealm(RealmModel) afterwards.
2. Managed RealmLists: It is possible to add unmanaged objects to a RealmList that is already managed. In that case the object will transparently be copied to Realm using Realm.copyToRealm(RealmModel) or Realm.copyToRealmOrUpdate(RealmModel) if it has a primary key.

Specified by:

set in interface java.util.List<E extends RealmModel>

Overrides:

set in class java.util.AbstractList<E extends RealmModel>

Parameters:

location - the index at which to put the specified object.

object - the object to add.

Returns:

the previous element at the index.

Throws:

java.lang.IllegalStateException - if Realm instance has been closed or parent object has been removed.

java.lang.IndexOutOfBoundsException - if location < 0 || location >= size().

move

public void move(int oldPos,
                 int newPos)

Moves an object from one position to another, while maintaining a fixed sized list. RealmObjects will be shifted so no null values are introduced.

Parameters:

oldPos - index of RealmObject to move.

newPos - target position. If newPos < oldPos the object at the location will be shifted to the right. If oldPos < newPos, indexes > oldPos will be shifted once to the left.

Throws:

java.lang.IllegalStateException - if Realm instance has been closed or parent object has been removed.

java.lang.IndexOutOfBoundsException - if any position is outside [0, size()].

clear

public void clear()

Removes all elements from this list, leaving it empty. This method doesn't remove the objects from the Realm.

Specified by:

clear in interface java.util.Collection<E extends RealmModel>

Specified by:

clear in interface java.util.List<E extends RealmModel>

Overrides:

clear in class java.util.AbstractList<E extends RealmModel>

Throws:

java.lang.IllegalStateException - if Realm instance has been closed or parent object has been removed.

See Also:

List.isEmpty(), List.size(), deleteAllFromRealm()

remove

public E remove(int location)

Removes the object at the specified location from this list.

Specified by:

remove in interface java.util.List<E extends RealmModel>

Overrides:

remove in class java.util.AbstractList<E extends RealmModel>

Parameters:

location - the index of the object to remove.

Returns:

the removed object.

Throws:

java.lang.IllegalStateException - if Realm instance has been closed or parent object has been removed.

java.lang.IndexOutOfBoundsException - if location < 0 || location >= size().

remove

public boolean remove(java.lang.Object object)

Removes one instance of the specified object from this Collection if one is contained. This implementation iterates over this Collection and tests each element e returned by the iterator, whether e is equal to the given object. If object != null then this test is performed using object.equals(e), otherwise using object == null. If an element equal to the given object is found, then the remove method is called on the iterator and true is returned, false otherwise. If the iterator does not support removing elements, an UnsupportedOperationException is thrown.

Specified by:

remove in interface java.util.Collection<E extends RealmModel>

Specified by:

remove in interface java.util.List<E extends RealmModel>

Overrides:

remove in class java.util.AbstractCollection<E extends RealmModel>

Parameters:

object - the object to remove.

Returns:

true if this Collection is modified, false otherwise.

Throws:

java.lang.ClassCastException - if the object passed is not of the correct type.

java.lang.NullPointerException - if object is null.

removeAll

public boolean removeAll(java.util.Collection<?> collection)

Removes all occurrences in this Collection of each object in the specified Collection. After this method returns none of the elements in the passed Collection can be found in this Collection anymore.

This implementation iterates over the Collection and tests each element e returned by the iterator, whether it is contained in the specified Collection. If this test is positive, then the remove method is called on the iterator.

Specified by:

removeAll in interface java.util.Collection<E extends RealmModel>

Specified by:

removeAll in interface java.util.List<E extends RealmModel>

Overrides:

removeAll in class java.util.AbstractCollection<E extends RealmModel>

Parameters:

collection - the collection of objects to remove.

Returns:

true if this Collection is modified, false otherwise.

Throws:

java.lang.ClassCastException - if one or more elements of collection isn't of the correct type.

java.lang.NullPointerException - if collection is null.

deleteFirstFromRealm

public boolean deleteFirstFromRealm()

Deletes the first object from the Realm. This also removes it from this collection.

Specified by:

deleteFirstFromRealm in interface OrderedRealmCollection<E extends RealmModel>

Returns:

true if an object was deleted, false otherwise.

deleteLastFromRealm

public boolean deleteLastFromRealm()

Deletes the last object from the Realm. This also removes it from this collection.

Specified by:

deleteLastFromRealm in interface OrderedRealmCollection<E extends RealmModel>

Returns:

true if an object was deleted, false otherwise.

get

public E get(int location)

Returns the element at the specified location in this list.

Specified by:

get in interface java.util.List<E extends RealmModel>

Specified by:

get in class java.util.AbstractList<E extends RealmModel>

Parameters:

location - the index of the element to return.

Returns:

the element at the specified index.

Throws:

java.lang.IllegalStateException - if Realm instance has been closed or parent object has been removed.

java.lang.IndexOutOfBoundsException - if location < 0 || location >= size().

first

public E first()

Gets the first object from the collection.

Specified by:

first in interface OrderedRealmCollection<E extends RealmModel>

Returns:

the first object.

last

public E last()

Gets the last object from the collection.

Specified by:

last in interface OrderedRealmCollection<E extends RealmModel>

Returns:

the last object.

sort

public RealmResults<E> sort(java.lang.String fieldName)

Sorts a collection based on the provided field in ascending order.

Specified by:

sort in interface OrderedRealmCollection<E extends RealmModel>

Parameters:

fieldName - the field name to sort by. Only fields of type boolean, short, int, long, float, double, Date, and String are supported.

Returns:

a new sorted RealmResults will be created and returned. The original collection stays unchanged.

sort

public RealmResults<E> sort(java.lang.String fieldName,
                            Sort sortOrder)

Sorts a collection based on the provided field and sort order.

Specified by:

sort in interface OrderedRealmCollection<E extends RealmModel>

Parameters:

fieldName - the field name to sort by. Only fields of type boolean, short, int, long, float, double, Date, and String are supported.

sortOrder - the direction to sort by.

Returns:

a new sorted RealmResults will be created and returned. The original collection stays unchanged.

sort

public RealmResults<E> sort(java.lang.String fieldName1,
                            Sort sortOrder1,
                            java.lang.String fieldName2,
                            Sort sortOrder2)

Sorts a collection based on the provided fields and sort orders.

Specified by:

sort in interface OrderedRealmCollection<E extends RealmModel>

Parameters:

fieldName1 - first field name. Only fields of type boolean, short, int, long, float, double, Date, and String are supported.

sortOrder1 - sort order for first field.

fieldName2 - second field name. Only fields of type boolean, short, int, long, float, double, Date, and String are supported.

sortOrder2 - sort order for second field.

Returns:

a new sorted RealmResults will be created and returned. The original collection stays unchanged.

sort

public RealmResults<E> sort(java.lang.String[] fieldNames,
                            Sort[] sortOrders)

Sorts a collection based on the provided fields and sort orders.

Specified by:

sort in interface OrderedRealmCollection<E extends RealmModel>

Parameters:

fieldNames - an array of field names to sort by. Only fields of type boolean, short, int, long, float, double, Date, and String are supported.

sortOrders - the directions to sort by.

Returns:

a new sorted RealmResults will be created and returned. The original collection stays unchanged.

deleteFromRealm

public void deleteFromRealm(int location)

Deletes the object at the given index from the Realm. This also removes it from the collection.

Specified by:

deleteFromRealm in interface OrderedRealmCollection<E extends RealmModel>

Parameters:

location - the array index identifying the object to be removed.

size

public int size()

Returns the number of elements in this List.

Specified by:

size in interface java.util.Collection<E extends RealmModel>

Specified by:

size in interface java.util.List<E extends RealmModel>

Specified by:

size in class java.util.AbstractCollection<E extends RealmModel>

Returns:

the number of elements in this List.

Throws:

java.lang.IllegalStateException - if Realm instance has been closed or parent object has been removed.

where

public RealmQuery<E> where()

Returns a RealmQuery, which can be used to query for specific objects of this class.

Specified by:

where in interface RealmCollection<E extends RealmModel>

Returns:

a RealmQuery object.

Throws:

java.lang.IllegalStateException - if Realm instance has been closed or parent object has been removed.

See Also:

RealmQuery

min

public java.lang.Number min(java.lang.String fieldName)

Finds the minimum value of a field.

Specified by:

min in interface RealmCollection<E extends RealmModel>

Parameters:

fieldName - the field to look for a minimum on. Only number fields are supported.

Returns:

if no objects exist or they all have null as the value for the given field, null will be returned. Otherwise the minimum value is returned. When determining the minimum value, objects with null values are ignored.

max

public java.lang.Number max(java.lang.String fieldName)

Finds the maximum value of a field.

Specified by:

max in interface RealmCollection<E extends RealmModel>

Parameters:

fieldName - the field to look for a maximum on. Only number fields are supported.

Returns:

if no objects exist or they all have null as the value for the given field, null will be returned. Otherwise the maximum value is returned. When determining the maximum value, objects with null values are ignored.

sum

public java.lang.Number sum(java.lang.String fieldName)

Calculates the sum of a given field.

Specified by:

sum in interface RealmCollection<E extends RealmModel>

Parameters:

fieldName - the field to sum. Only number fields are supported.

Returns:

the sum. If no objects exist or they all have null as the value for the given field, 0 will be returned. When computing the sum, objects with null values are ignored.

average

public double average(java.lang.String fieldName)

Returns the average of a given field.

Specified by:

average in interface RealmCollection<E extends RealmModel>

Parameters:

fieldName - the field to calculate average on. Only number fields are supported.

Returns:

the average for the given field amongst objects in query results. This will be of type double for all types of number fields. If no objects exist or they all have null as the value for the given field, 0 will be returned. When computing the average, objects with null values are ignored.

maxDate

public java.util.Date maxDate(java.lang.String fieldName)

Finds the maximum date.

Specified by:

maxDate in interface RealmCollection<E extends RealmModel>

Parameters:

fieldName - the field to look for the maximum date. If fieldName is not of Date type, an exception is thrown.

Returns:

if no objects exist or they all have null as the value for the given date field, null will be returned. Otherwise the maximum date is returned. When determining the maximum date, objects with null values are ignored.

minDate

public java.util.Date minDate(java.lang.String fieldName)

Finds the minimum date.

Specified by:

minDate in interface RealmCollection<E extends RealmModel>

Parameters:

fieldName - the field to look for the minimum date. If fieldName is not of Date type, an exception is thrown.

Returns:

if no objects exist or they all have null as the value for the given date field, null will be returned. Otherwise the minimum date is returned. When determining the minimum date, objects with null values are ignored.

deleteAllFromRealm

public boolean deleteAllFromRealm()

This deletes all objects in the collection from the underlying Realm as well as from the collection.

Specified by:

deleteAllFromRealm in interface RealmCollection<E extends RealmModel>

Returns:

true if objects was deleted, false otherwise.

isLoaded

public boolean isLoaded()

Checks if a collection has finished loading its data yet.

Specified by:

isLoaded in interface RealmCollection<E extends RealmModel>

Returns:

true if data has been loaded and is available, false if data is still being loaded.

load

public boolean load()

Blocks the collection until all data are available.

Specified by:

load in interface RealmCollection<E extends RealmModel>

Returns:

true if the data could be successfully loaded, false otherwise.

contains

public boolean contains(java.lang.Object object)

Returns true if the list contains the specified element when attached to a Realm. This method will query the native Realm underlying storage engine to quickly find the specified element.

If the list is not attached to a Realm, the default List.contains(Object) implementation will occur.

Specified by:

contains in interface RealmCollection<E extends RealmModel>

Specified by:

contains in interface java.util.Collection<E extends RealmModel>

Specified by:

contains in interface java.util.List<E extends RealmModel>

Overrides:

contains in class java.util.AbstractCollection<E extends RealmModel>

Parameters:

object - the element whose presence in this list is to be tested.

Returns:

true if this list contains the specified element otherwise false.

iterator

public java.util.Iterator<E> iterator()

Specified by:

iterator in interface java.lang.Iterable<E extends RealmModel>

Specified by:

iterator in interface java.util.Collection<E extends RealmModel>

Specified by:

iterator in interface java.util.List<E extends RealmModel>

Overrides:

iterator in class java.util.AbstractList<E extends RealmModel>

listIterator

public java.util.ListIterator<E> listIterator()

Specified by:

listIterator in interface java.util.List<E extends RealmModel>

Overrides:

listIterator in class java.util.AbstractList<E extends RealmModel>

listIterator

public java.util.ListIterator<E> listIterator(int location)

Specified by:

listIterator in interface java.util.List<E extends RealmModel>

Overrides:

listIterator in class java.util.AbstractList<E extends RealmModel>

toString

public java.lang.String toString()

Overrides:

toString in class java.util.AbstractCollection<E extends RealmModel>