io.realm

Class RealmSet<E>

java.lang.Object

io.realm.RealmSet<E>

Type Parameters:

E - the type of the values stored in this set

All Implemented Interfaces:

RealmCollection<E>, Iterable<E>, Collection<E>, Set<E>

public class RealmSet<E>
extends Object
implements Set<E>, RealmCollection<E>

RealmSet is a collection that contains no duplicate elements.

Similarly to RealmLists, a RealmSet can operate in managed and unmanaged modes. In managed mode a RealmSet persists all its contents inside a Realm whereas in unmanaged mode it functions like a HashSet.

Managed RealmSets can only be created by Realm and will automatically update its content whenever the underlying Realm is updated. Managed RealmSet can only be accessed using the getter that points to a RealmSet field of a RealmObject.

Unmanaged elements in this set can be added to a Realm using the Realm.copyToRealm(Iterable, ImportFlag...) method.

Warning: the following methods are not supported for classes containing set fields yet:

• Realm.insert(RealmModel)
• Realm.insert(Collection)
• Realm.insertOrUpdate(RealmModel)
• Realm.insertOrUpdate(Collection)
• Realm.createAllFromJson(Class, String)
• Realm.createAllFromJson(Class, JSONArray)
• Realm.createAllFromJson(Class, InputStream)
• Realm.createObjectFromJson(Class, String)
• Realm.createObjectFromJson(Class, JSONObject)}
• Realm.createObjectFromJson(Class, InputStream)}
• Realm.createOrUpdateAllFromJson(Class, String)
• Realm.createOrUpdateAllFromJson(Class, JSONArray)
• Realm.createOrUpdateAllFromJson(Class, InputStream)
• Realm.createOrUpdateObjectFromJson(Class, String)
• Realm.createOrUpdateObjectFromJson(Class, JSONObject)
• Realm.createOrUpdateObjectFromJson(Class, InputStream)

Constructor Summary

Constructors

Constructor and Description
RealmSet() Instantiates a RealmSet in unmanaged mode.
RealmSet(io.realm.BaseRealm baseRealm, OsSet osSet, Class<E> valueClass) Instantiates a RealmSet in managed mode.
RealmSet(io.realm.BaseRealm baseRealm, OsSet osSet, String className) Instantiates a RealmSet in managed mode.
RealmSet(Collection<E> collection) Instantiates a RealmSet in unmanaged mode with another collection.

Method Summary

Modifier and Type	Method and Description
boolean	add(E e)
boolean	addAll(Collection<? extends E> c)
void	addChangeListener(RealmChangeListener<RealmSet<E>> listener) Adds a change listener to this RealmSet.
void	addChangeListener(SetChangeListener<E> listener) Adds a change listener to this RealmSet.
double	average(String fieldName) Returns the average of a given field.
void	clear()
boolean	contains(Object o) Tests whether this Collection contains the specified object.
boolean	containsAll(Collection<?> c)
boolean	deleteAllFromRealm() This deletes all objects in the collection from the underlying Realm as well as from the collection.
RealmSet<E>	freeze()
Class<E>	getValueClass()
String	getValueClassName()
boolean	isEmpty()
boolean	isFrozen()
boolean	isLoaded() Checks if a collection has finished loading its data yet.
boolean	isManaged() Checks if the collection is managed by Realm.
boolean	isValid() Checks if the collection is still valid to use, i.e., the Realm instance hasn't been closed.
Iterator<E>	iterator()
boolean	load() Blocks the collection until all data are available.
Number	max(String fieldName) Finds the maximum value of a field.
Date	maxDate(String fieldName) Finds the maximum date.
Number	min(String fieldName) Finds the minimum value of a field.
Date	minDate(String fieldName) Finds the minimum date.
boolean	remove(Object o)
boolean	removeAll(Collection<?> c)
void	removeAllChangeListeners() Removes all user-defined change listeners.
void	removeChangeListener(RealmChangeListener<RealmSet<E>> listener) Removes the specified change listener.
void	removeChangeListener(SetChangeListener<E> listener) Removes the specified change listener.
boolean	retainAll(Collection<?> c)
int	size()
Number	sum(String fieldName) Calculates the sum of a given field.
Object[]	toArray()
<T> T[]	toArray(T[] a)
RealmQuery<E>	where() Returns a RealmQuery, which can be used to query for specific objects of this class.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Set

equals, hashCode, spliterator

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream

Methods inherited from interface java.lang.Iterable

forEach

Constructor Detail

RealmSet

public RealmSet()

Instantiates a RealmSet in unmanaged mode.

RealmSet

public RealmSet(Collection<E> collection)

Instantiates a RealmSet in unmanaged mode with another collection.

Parameters:

collection - the collection with which the set will be initially populated.

RealmSet

public RealmSet(io.realm.BaseRealm baseRealm,
                OsSet osSet,
                Class<E> valueClass)

Instantiates a RealmSet in managed mode. This constructor is used internally by Realm.

Parameters:

baseRealm -

osSet -

valueClass -

RealmSet

public RealmSet(io.realm.BaseRealm baseRealm,
                OsSet osSet,
                String className)

Instantiates a RealmSet in managed mode. This constructor is used internally by a Dynamic Realm.

Parameters:

baseRealm -

osSet -

className -

Method Detail

isManaged

public boolean isManaged()

Checks if the collection is managed by Realm. A managed collection is just a wrapper around the data in the underlying Realm file. On Looper threads, a managed collection will be live-updated so it always points to the latest data. Managed collections are thread confined so that they cannot be accessed from other threads than the one that created them.

If this method returns false, the collection is unmanaged. An unmanaged collection is just a normal java collection, so it will not be live updated.

Specified by:

isManaged in interface RealmCollection<E>

Returns:

true if this is a managed RealmCollection, false otherwise.

isValid

public boolean isValid()

Checks if the collection is still valid to use, i.e., the Realm instance hasn't been closed. It will always return true for an unmanaged collection.

Specified by:

isValid in interface RealmCollection<E>

Returns:

true if it is still valid to use or an unmanaged collection, false otherwise.

isFrozen

public boolean isFrozen()

size

public int size()

Specified by:

size in interface Collection<E>

Specified by:

size in interface Set<E>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Collection<E>

Specified by:

isEmpty in interface Set<E>

contains

public boolean contains(Object o)

Tests whether this Collection contains the specified object. Returns true if and only if at least one element elem in this Collection meets following requirement: (object==null ? elem==null : object.equals(elem)).

Specified by:

contains in interface RealmCollection<E>

Specified by:

contains in interface Collection<E>

Specified by:

contains in interface Set<E>

Parameters:

o - the object to search for.

Returns:

true if object is an element of this Collection, false otherwise.

iterator

public Iterator<E> iterator()

Specified by:

iterator in interface Iterable<E>

Specified by:

iterator in interface Collection<E>

Specified by:

iterator in interface Set<E>

toArray

public Object[] toArray()

Specified by:

toArray in interface Collection<E>

Specified by:

toArray in interface Set<E>

toArray

public <T> T[] toArray(T[] a)

Specified by:

toArray in interface Collection<E>

Specified by:

toArray in interface Set<E>

add

public boolean add(E e)

Specified by:

add in interface Collection<E>

Specified by:

add in interface Set<E>

remove

public boolean remove(Object o)

Specified by:

remove in interface Collection<E>

Specified by:

remove in interface Set<E>

containsAll

public boolean containsAll(Collection<?> c)

Specified by:

containsAll in interface Collection<E>

Specified by:

containsAll in interface Set<E>

addAll

public boolean addAll(Collection<? extends E> c)

Specified by:

addAll in interface Collection<E>

Specified by:

addAll in interface Set<E>

retainAll

public boolean retainAll(Collection<?> c)

Specified by:

retainAll in interface Collection<E>

Specified by:

retainAll in interface Set<E>

removeAll

public boolean removeAll(Collection<?> c)

Specified by:

removeAll in interface Collection<E>

Specified by:

removeAll in interface Set<E>

clear

public void clear()

Specified by:

clear in interface Collection<E>

Specified by:

clear in interface Set<E>

freeze

public RealmSet<E> freeze()

addChangeListener

public void addChangeListener(RealmChangeListener<RealmSet<E>> listener)

Adds a change listener to this RealmSet.

Registering a change listener will not prevent the underlying RealmSet from being garbage collected. If the RealmSet is garbage collected, the change listener will stop being triggered. To avoid this, keep a strong reference for as long as appropriate e.g. in a class variable.

 
 public class MyActivity extends Activity {

     private RealmSet<Dog> dogs; // Strong reference to keep listeners alive

     \@Override
     protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       dogs = realm.where(Person.class).findFirst().getDogs();
       dogs.addChangeListener(new RealmChangeListener<RealmSet<Dog>>() {
           \@Override
           public void onChange(RealmSet<Dog> map) {
               // React to change
           }
       });
     }
 }
 
 

Parameters:

listener - the listener to be notified.

Throws:

IllegalArgumentException - if the change listener is null.

IllegalStateException - if you try to add a listener from a non-Looper or IntentService thread.

addChangeListener

public void addChangeListener(SetChangeListener<E> listener)

Adds a change listener to this RealmSet.

Registering a change listener will not prevent the underlying RealmSet from being garbage collected. If the RealmSet is garbage collected, the change listener will stop being triggered. To avoid this, keep a strong reference for as long as appropriate e.g. in a class variable.

 
 public class MyActivity extends Activity {

     private RealmSet<Dog> dogs; // Strong reference to keep listeners alive

     \@Override
     protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       dogs = realm.where(Person.class).findFirst().getDogs();
       dogs.addChangeListener(new SetChangeListener<Dog>() {
           \@Override
           public void onChange(RealmSet<Dog> set, SetChangeSet changeSet) {
               // React to change
           }
       });
     }
 }
 
 

Parameters:

listener - the listener to be notified.

Throws:

IllegalArgumentException - if the change listener is null.

IllegalStateException - if you try to add a listener from a non-Looper or IntentService thread.

removeChangeListener

public void removeChangeListener(RealmChangeListener<RealmSet<E>> listener)

Removes the specified change listener.

Parameters:

listener - the change listener to be removed.

Throws:

IllegalArgumentException - if the change listener is null.

IllegalStateException - if you try to remove a listener from a non-Looper Thread.

removeChangeListener

public void removeChangeListener(SetChangeListener<E> listener)

Removes the specified change listener.

Parameters:

listener - the change listener to be removed.

Throws:

IllegalArgumentException - if the change listener is null.

IllegalStateException - if you try to remove a listener from a non-Looper Thread.

removeAllChangeListeners

public void removeAllChangeListeners()

Removes all user-defined change listeners.

Throws:

IllegalStateException - if you try to remove listeners from a non-Looper Thread.

See Also:

RealmChangeListener

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>

Returns:

a RealmQuery object.

Throws:

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

See Also:

RealmQuery

min

public Number min(String fieldName)

Finds the minimum value of a field.

Specified by:

min in interface RealmCollection<E>

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 Number max(String fieldName)

Finds the maximum value of a field.

Specified by:

max in interface RealmCollection<E>

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 Number sum(String fieldName)

Calculates the sum of a given field.

Specified by:

sum in interface RealmCollection<E>

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(String fieldName)

Returns the average of a given field.

Specified by:

average in interface RealmCollection<E>

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 Date maxDate(String fieldName)

Finds the maximum date.

Specified by:

maxDate in interface RealmCollection<E>

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 Date minDate(String fieldName)

Finds the minimum date.

Specified by:

minDate in interface RealmCollection<E>

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>

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>

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>

Returns:

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

getValueClassName

public String getValueClassName()

getValueClass

public Class<E> getValueClass()