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io.realm

Class Realm

On this page

  • io.realm
  • Nested Class Summary
  • Field Summary
  • Method Summary
  • Inherited Methods
  • Field Detail
  • DEFAULT_REALM_NAME
  • ENCRYPTION_KEY_LENGTH
  • Method Detail
  • addChangeListener
  • asFlowable
  • compactRealm
  • copyFromRealm
  • copyToRealm
  • copyToRealmOrUpdate
  • createAllFromJson
  • createEmbeddedObject
  • createObject
  • createObjectFromJson
  • createOrUpdateAllFromJson
  • createOrUpdateObjectFromJson
  • delete
  • deleteRealm
  • executeTransaction
  • executeTransactionAsync
  • freeze
  • getApplicationContext
  • getDefaultConfiguration
  • getDefaultInstance
  • getDefaultModule
  • getGlobalInstanceCount
  • getInstance
  • getInstanceAsync
  • getLocalInstanceCount
  • getSchema
  • init
  • insert
  • insertOrUpdate
  • isEmpty
  • migrateRealm
  • removeAllChangeListeners
  • removeChangeListener
  • removeDefaultConfiguration
  • setDefaultConfiguration
  • where

io.realm

java.lang.Object
io.realm.BaseRealm
io.realm.Realm

The Realm class is the storage and transactional manager of your object persistent store. It is in charge of creating instances of your RealmObjects. Objects within a Realm can be queried and read at any time. Creating, modifying, and deleting objects must be done while inside a transaction. See executeTransaction(Transaction)

The transactions ensure that multiple instances (on multiple threads) can access the same objects in a consistent state with full ACID guarantees.

It is important to remember to call the close() method when done with a Realm instance. Failing to do so can lead to java.lang.OutOfMemoryError as the native resources cannot be freed.

Realm instances cannot be used across different threads. This means that you have to open an instance on each thread you want to use Realm. Realm instances are cached automatically per thread using reference counting, so as long as the reference count doesn't reach zero, calling getInstance(RealmConfiguration) will just return the cached Realm and should be considered a lightweight operation.

For the UI thread this means that opening and closing Realms should occur in either onCreate/onDestroy or onStart/onStop.

Realm instances coordinate their state across threads using the android.os.Handler mechanism. This also means that Realm instances on threads without an android.os.Looper cannot receive updates unless refresh() is manually called.

A standard pattern for working with Realm in Android activities can be seen below:

public class RealmApplication extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        // The Realm file will be located in package's "files" directory.
        RealmConfiguration realmConfig = new RealmConfiguration.Builder(this).build();
        Realm.setDefaultConfiguration(realmConfig);
    }
}
public class RealmActivity extends Activity {
  private Realm realm;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.layout_main);
    realm = Realm.getDefaultInstance();
  }
  @Override
  protected void onDestroy() {
    super.onDestroy();
    realm.close();
  }
}

Realm supports String and byte fields containing up to 16 MB.

Tip

See also:

  • ACID

  • Examples using Realm

Nested Class Summary

Modifier and Type
Class and Description
public static interface
public abstract static

Field Summary

Modifier and Type
Field and Description
public static final String
public static final int

ENCRYPTION_KEY_LENGTH

The required length for encryption keys used to encrypt Realm data.

Method Summary

Modifier and Type
Method and Description
public void
addChangeListener (
io.realm.RealmChangeListener<io.realm.Realm> listener
)

Adds a change listener to the Realm.

public <any>
asFlowable ()

Returns an RxJava Flowable that monitors changes to this Realm.

public static boolean
compactRealm (
RealmConfiguration configuration
)

Compacts a Realm file.

public E
copyFromRealm <E >(
E realmObject,
int maxDepth
)

Makes an unmanaged in-memory copy of an already persisted RealmObject .

public E
copyFromRealm <E >(
E realmObject
)

Makes an unmanaged in-memory copy of an already persisted RealmObject .

public List
copyFromRealm <E >(
java.lang.Iterable<E> realmObjects,
int maxDepth
)

Makes an unmanaged in-memory copy of already persisted RealmObjects.

public List
copyFromRealm <E >(
java.lang.Iterable<E> realmObjects
)

Makes an unmanaged in-memory copy of already persisted RealmObjects.

public List
copyToRealm <E >(
java.lang.Iterable<E> objects,
io.realm.ImportFlag[] flags
)

Copies a collection of RealmObjects to the Realm instance and returns their copy.

public E
copyToRealm <E >(
E object,
io.realm.ImportFlag[] flags
)

Copies a RealmObject to the Realm instance and returns the copy.

public List
copyToRealmOrUpdate <E >(
java.lang.Iterable<E> objects,
io.realm.ImportFlag[] flags
)

Updates a list of existing RealmObjects that is identified by their io.realm.annotations.PrimaryKey or creates a new copy if no existing object could be found.

public E
copyToRealmOrUpdate <E >(
E object,
io.realm.ImportFlag[] flags
)

Updates an existing RealmObject that is identified by the same io.realm.annotations.PrimaryKey or creates a new copy if no existing object could be found.

public void
createAllFromJson <E >(
java.lang.Class<E> clazz,
JSONArray json
)

Creates a Realm object for each object in a JSON array.

public E
createEmbeddedObject <E >(
java.lang.Class<E> clazz,
RealmModel parentObject,
String parentProperty
)

Instantiates and adds a new embedded object to the Realm.

public E
createObject <E >(
java.lang.Class<E> clazz,
Object primaryKeyValue
)

Instantiates and adds a new object to the Realm with the primary key value already set.

public E
createObject <E >(
java.lang.Class<E> clazz
)

Instantiates and adds a new object to the Realm.

public E
createObjectFromJson <E >(
java.lang.Class<E> clazz,
JSONObject json
)

Creates a Realm object pre-filled with data from a JSON object.

public void
createOrUpdateAllFromJson <E >(
java.lang.Class<E> clazz,
JSONArray json
)

Tries to update a list of existing objects identified by their primary key with new JSON data.

public E
createOrUpdateObjectFromJson <E >(
java.lang.Class<E> clazz,
JSONObject json
)

Tries to update an existing object defined by its primary key with new JSON data.

public void
delete (
java.lang.Class<? extends io.realm.RealmModel> clazz
)

Deletes all objects of the specified class from the Realm.

public static boolean
deleteRealm (
RealmConfiguration configuration
)

Deletes the Realm file along with the related temporary files specified by the given RealmConfiguration from the filesystem.

public void
executeTransaction (
Realm.Transaction transaction
)

Executes a given transaction on the Realm.

executeTransactionAsync (
Realm.Transaction transaction,
Realm.Transaction.OnSuccess onSuccess,
Realm.Transaction.OnError onError
)

Similar to executeTransactionAsync(Transaction) , but also accepts an OnSuccess and OnError callbacks.

executeTransactionAsync (
Realm.Transaction transaction,
Realm.Transaction.OnError onError
)

Similar to executeTransactionAsync(Transaction) , but also accepts an OnError callback.

executeTransactionAsync (
Realm.Transaction transaction,
Realm.Transaction.OnSuccess onSuccess
)

Similar to executeTransactionAsync(Transaction) , but also accepts an OnSuccess callback.

executeTransactionAsync (
Realm.Transaction transaction
)

Similar to executeTransaction(Transaction) but runs asynchronously on a worker thread.

public Realm
freeze ()

Returns a frozen snapshot of the current Realm.

public static Context
getApplicationContext ()

Get the application context used when initializing Realm with Realm.init(Context) or Realm.init(Context, String) .

public static RealmConfiguration
getDefaultConfiguration ()

Returns the default configuration for getDefaultInstance() .

public static Realm
getDefaultInstance ()

Realm static constructor that returns the Realm instance defined by the io.realm.RealmConfiguration set by setDefaultConfiguration(RealmConfiguration)

public static Object
getDefaultModule ()

Returns the default Realm module.

public static int
getGlobalInstanceCount (
RealmConfiguration configuration
)

Returns the current number of open Realm instances across all threads in current process that are using this configuration.

public static Realm
getInstance (
RealmConfiguration configuration
)

Realm static constructor that returns the Realm instance defined by provided io.realm.RealmConfiguration

public static RealmAsyncTask
getInstanceAsync (
RealmConfiguration configuration,
Realm.Callback callback
)

The creation of the first Realm instance per RealmConfiguration in a process can take some time as all initialization code need to run at that point (setting up the Realm, validating schemas and creating initial data).

public static int
getLocalInstanceCount (
RealmConfiguration configuration
)

Returns the current number of open Realm instances on the thread calling this method.

getSchema ()

Returns the schema for this Realm.

public static synchronized void
init (
Context context,
String userAgent
)

Initializes the Realm library and creates a default configuration that is ready to use.

public static synchronized void
init (
Context context
)

Initializes the Realm library and creates a default configuration that is ready to use.

public void
insert (
RealmModel object
)

Inserts an unmanaged RealmObject.

public void
insert (
java.util.Collection<? extends io.realm.RealmModel> objects
)

Inserts a list of an unmanaged RealmObjects.

public void
insertOrUpdate (
RealmModel object
)

Inserts or updates an unmanaged RealmObject.

public void
insertOrUpdate (
java.util.Collection<? extends io.realm.RealmModel> objects
)

Inserts or updates a list of unmanaged RealmObjects.

public boolean
isEmpty ()

Checks if this io.realm.Realm contains any objects.

public static void
migrateRealm (
RealmConfiguration configuration,
RealmMigration migration
)

Manually triggers a migration on a RealmMigration.

public static void
migrateRealm (
RealmConfiguration configuration
)

Manually triggers the migration associated with a given RealmConfiguration.

public void
removeAllChangeListeners ()

Removes all user-defined change listeners.

public void
removeChangeListener (
io.realm.RealmChangeListener<io.realm.Realm> listener
)

Removes the specified change listener.

public static void
removeDefaultConfiguration ()

Removes the current default configuration (if any).

public static void
public RealmQuery
where <E >(
java.lang.Class<E> clazz
)

Returns a typed RealmQuery, which can be used to query for specific objects of this type

Inherited Methods

  • Methods inherited from class java.lang.Object : getClass , hashCode , equals , clone , toString , notify , notifyAll , wait , wait , wait , finalize

  • Methods inherited from class io.realm.BaseRealm: setAutoRefresh , isAutoRefresh , refresh , isInTransaction , addListener , removeListener , asFlowable , removeAllListeners , writeCopyTo , writeEncryptedCopyTo , waitForChange , stopWaitForChange , beginTransaction , commitTransaction , cancelTransaction , freeze , isFrozen , getNumberOfActiveVersions , checkIfValid , checkAllowQueriesOnUiThread , checkAllowWritesOnUiThread , checkIfInTransaction , checkIfValidAndInTransaction , getPath , getConfiguration , getVersion , close , isClosed , isEmpty , getSchema , getSubscriptions , deleteAll , migrateRealm , finalize

Field Detail

DEFAULT_REALM_NAME

ENCRYPTION_KEY_LENGTH

The required length for encryption keys used to encrypt Realm data.

Method Detail

addChangeListener

Adds a change listener to the Realm.The listeners will be executed when changes are committed by this or another thread.

Realm instances are per thread singletons and cached, so listeners should be removed manually even if calling close(). Otherwise there is a risk of memory leaks.

Parameters

  • listener - the change listener.

Throws

Tip

See also:

asFlowable

public <any> asFlowable ()

Returns an RxJava Flowable that monitors changes to this Realm. It will emit the current state when subscribed to. Items will continually be emitted as the Realm is updated - onComplete will never be called.

Items emitted from Realm Flowables are frozen (See freeze(). This means that they are immutable and can be read on any thread.

Realm Flowables always emit items from the thread holding the live Realm. This means that if you need to do further processing, it is recommend to observe the values on a computation scheduler:

realm.asFlowable()
 .observeOn(Schedulers.computation())
 .map(rxRealm -> doExpensiveWork(rxRealm))
 .observeOn(AndroidSchedulers.mainThread())
 .subscribe( ... );

If you would like the asFlowable() to stop emitting items, you can instruct RxJava to only emit only the first item by using the first() operator:

realm.asFlowable().first().subscribe( ... ); // You only get the results once

Returns

RxJava Observable that only calls onNext . It will never call onComplete or OnError .

Overrides

asFlowable in class BaseRealm

compactRealm

public static boolean compactRealm (
RealmConfiguration configuration
)

Compacts a Realm file. A Realm file usually contain free/unused space. This method removes this free space and the file size is thereby reduced. Objects within the Realm files are untouched.The file must be closed before this method is called, otherwise false will be returned.

The file system should have free space for at least a copy of the Realm file.
The Realm file is left untouched if any file operation fails.

Parameters

Returns

true if successful, false if any file operation failed.

copyFromRealm

public E copyFromRealm <E >(
E realmObject,
int maxDepth
)

Makes an unmanaged in-memory copy of an already persisted RealmObject . This is a deep copy that will copy all referenced objects up to the defined depth.

The copied object(s) are all detached from Realm and they will no longer be automatically updated. This means that the copied objects might contain data that are no longer consistent with other managed Realm objects.

*WARNING*: Any changes to copied objects can be merged back into Realm using copyToRealmOrUpdate(RealmModel, ImportFlag...) , but all fields will be overridden, not just those that were changed. This includes references to other objects even though they might be null due to maxDepth being reached. This can also potentially override changes made by other threads. This behaviour can be modified using ImportFlag s.

Type Parameters

  • E - type of object.

Parameters

  • realmObject - RealmObject to copy.

  • maxDepth - limit of the deep copy. All references after this depth will be null . Starting depth is 0 .

Returns

an in-memory detached copy of the managed RealmObject .

Throws

Tip

See also:

public E copyFromRealm <E >(
E realmObject
)

Makes an unmanaged in-memory copy of an already persisted RealmObject . This is a deep copy that will copy all referenced objects.

The copied object(s) are all detached from Realm and they will no longer be automatically updated. This means that the copied objects might contain data that are no longer consistent with other managed Realm objects.

*WARNING*: Any changes to copied objects can be merged back into Realm using copyToRealmOrUpdate(RealmModel, ImportFlag...) , but all fields will be overridden, not just those that were changed. This includes references to other objects, and can potentially override changes made by other threads. This behaviour can be modified using ImportFlag s.

Type Parameters

  • E - type of object.

Parameters

Returns

an in-memory detached copy of the managed RealmObject .

Throws

Tip

See also:

public List copyFromRealm <E >(
java.lang.Iterable<E> realmObjects,
int maxDepth
)

Makes an unmanaged in-memory copy of already persisted RealmObjects. This is a deep copy that will copy all referenced objects up to the defined depth.The copied objects are all detached from Realm and they will no longer be automatically updated. This means that the copied objects might contain data that are no longer consistent with other managed Realm objects.

*WARNING*: Any changes to copied objects can be merged back into Realm using copyToRealmOrUpdate(Iterable, ImportFlag...) , but all fields will be overridden, not just those that were changed. This includes references to other objects even though they might be null due to maxDepth being reached. This can also potentially override changes made by other threads. This behaviour can be modified using ImportFlag s.

Type Parameters

  • E - type of object.

Parameters

  • realmObjects - RealmObjects to copy.

  • maxDepth - limit of the deep copy. All references after this depth will be null . Starting depth is 0 .

Returns

an in-memory detached copy of the RealmObjects.

Throws

Tip

See also:

public List copyFromRealm <E >(
java.lang.Iterable<E> realmObjects
)

Makes an unmanaged in-memory copy of already persisted RealmObjects. This is a deep copy that will copy all referenced objects.The copied objects are all detached from Realm and they will no longer be automatically updated. This means that the copied objects might contain data that are no longer consistent with other managed Realm objects.

*WARNING*: Any changes to copied objects can be merged back into Realm using copyToRealmOrUpdate(RealmModel, ImportFlag...) , but all fields will be overridden, not just those that were changed. This includes references to other objects, and can potentially override changes made by other threads. This behaviour can be modified using ImportFlag s.

Type Parameters

  • E - type of object.

Parameters

  • realmObjects - RealmObjects to copy.

Returns

an in-memory detached copy of managed RealmObjects.

Throws

Tip

See also:

copyToRealm

Copies a collection of RealmObjects to the Realm instance and returns their copy. Any further changes to the original RealmObjects will not be reflected in the Realm copies. This is a deep copy i.e., all referenced objects will be copied. Objects already in this Realm will be ignored.Please note, copying an object will copy all field values. Any unset field in the objects and child objects will be set to their default value if not provided.

Parameters

  • objects - the RealmObjects to copy to the Realm.

  • flags - any flag that modifies the behaviour of inserting the data into the Realm.

Returns

a list of the the converted RealmObjects that all has their properties managed by the Realm.

Throws

public E copyToRealm <E >(
E object,
io.realm.ImportFlag[] flags
)

Copies a RealmObject to the Realm instance and returns the copy. Any further changes to the original RealmObject will not be reflected in the Realm copy. This is a deep copy, so all referenced objects will be copied. Objects already in this Realm will be ignored.Please note, copying an object will copy all field values. Any unset field in this and child objects will be set to their default value if not provided.

Parameters

  • object - the io.realm.RealmObject to copy to the Realm.

  • flags - any flag that modifies the behaviour of inserting the data into the Realm.

Returns

a managed RealmObject with its properties backed by the Realm.

Throws

copyToRealmOrUpdate

Updates a list of existing RealmObjects that is identified by their io.realm.annotations.PrimaryKey or creates a new copy if no existing object could be found. This is a deep copy or update i.e., all referenced objects will be either copied or updated.

Please note, copying an object will copy all field values. Any unset field in the objects and child objects will be set to their default value if not provided.

Parameters

  • objects - a list of objects to update or copy into Realm.

  • flags - any flag that modifies the behaviour of inserting the data into the Realm.

Returns

a list of all the new or updated RealmObjects.

Throws

Tip

See also:

public E copyToRealmOrUpdate <E >(
E object,
io.realm.ImportFlag[] flags
)

Updates an existing RealmObject that is identified by the same io.realm.annotations.PrimaryKey or creates a new copy if no existing object could be found. This is a deep copy or update i.e., all referenced objects will be either copied or updated.

Please note, copying an object will copy all field values. Any unset field in the object and child objects will be set to their default value if not provided.

Parameters

  • object - io.realm.RealmObject to copy or update.

  • flags - any flag that modifies the behaviour of inserting the data into the Realm.

Returns

the new or updated RealmObject with all its properties backed by the Realm.

Throws

Tip

See also:

createAllFromJson

public void createAllFromJson <E >(
java.lang.Class<E> clazz,
JSONArray json
)

Creates a Realm object for each object in a JSON array. This must be done within a transaction.JSON properties with unknown properties will be ignored. If a RealmObject field is not present in the JSON object the RealmObject field will be set to the default value for that type.

This method currently does not support value list field.

Parameters

  • clazz - type of Realm objects to create.

  • json - an array where each JSONObject must map to the specified class.

Throws

Tip

See also:

createEmbeddedObject

public E createEmbeddedObject <E >(
java.lang.Class<E> clazz,
RealmModel parentObject,
String parentProperty
)

Instantiates and adds a new embedded object to the Realm.This method should only be used to create objects of types marked as embedded.

Parameters

  • clazz - the Class of the object to create. It must be marked with @RealmClass(embedded = true) .

  • parentObject - The parent object which should hold a reference to the embedded object.

  • parentProperty - the property in the parent class which holds the reference. If the parent property is a list the embedded object will be added to the end of that list.

Returns

the newly created embedded object.

Throws

  • IllegalArgumentException - if clazz is not an embedded class or if the property in the parent class cannot hold objects of the appropriate type.

Tip

See also:

createObject

public E createObject <E >(
java.lang.Class<E> clazz,
Object primaryKeyValue
)

Instantiates and adds a new object to the Realm with the primary key value already set.If the value violates the primary key constraint, no object will be added and a RealmException will be thrown. The default value for primary key provided by the model class will be ignored.

Parameters

  • clazz - the Class of the object to create.

  • primaryKeyValue - value for the primary key field.

Returns

the new object.

Throws

public E createObject <E >(
java.lang.Class<E> clazz
)

Instantiates and adds a new object to the Realm.This method is only available for model classes with no @PrimaryKey annotation. If you like to create an object that has a primary key, use createObject(Class, Object) or copyToRealm(RealmModel, ImportFlag...) instead.

Parameters

  • clazz - the Class of the object to create.

Returns

the new object.

Throws

  • RealmException - if the primary key is defined in the model class or an object cannot be created.

Tip

See also:

createObjectFromJson

public E createObjectFromJson <E >(
java.lang.Class<E> clazz,
JSONObject json
)

Creates a Realm object pre-filled with data from a JSON object. This must be done inside a transaction. JSON properties with unknown properties will be ignored. If a RealmObject field is not present in the JSON object the RealmObject field will be set to the default value for that type.

This method currently does not support value list field.

Parameters

  • clazz - type of Realm object to create.

  • json - the JSONObject with object data.

Returns

created object or null if no JSON data was provided.

Throws

Tip

See also:

createOrUpdateAllFromJson

public void createOrUpdateAllFromJson <E >(
java.lang.Class<E> clazz,
JSONArray json
)

Tries to update a list of existing objects identified by their primary key with new JSON data. If an existing object could not be found in the Realm, a new object will be created. This must happen within a transaction. If updating a RealmObject and a field is not found in the JSON object, that field will not be updated. If a new RealmObject is created and a field is not found in the JSON object, that field will be assigned the default value for the field type.

This method currently does not support value list field.

Parameters

  • clazz - type of io.realm.RealmObject to create or update. It must have a primary key defined.

  • json - array with object data.

Throws

Tip

See also:

createOrUpdateObjectFromJson

public E createOrUpdateObjectFromJson <E >(
java.lang.Class<E> clazz,
JSONObject json
)

Tries to update an existing object defined by its primary key with new JSON data. If no existing object could be found a new object will be saved in the Realm. This must happen within a transaction. If updating a RealmObject and a field is not found in the JSON object, that field will not be updated. If a new RealmObject is created and a field is not found in the JSON object, that field will be assigned the default value for the field type.

This method currently does not support value list field.

Parameters

  • clazz - Type of io.realm.RealmObject to create or update. It must have a primary key defined.

  • json - org.json.JSONObject with object data.

Returns

created or updated io.realm.RealmObject .

Throws

Tip

See also:

delete

Deletes all objects of the specified class from the Realm.

Parameters

  • clazz - the class which objects should be removed.

Throws

deleteRealm

public static boolean deleteRealm (
RealmConfiguration configuration
)

Deletes the Realm file along with the related temporary files specified by the given RealmConfiguration from the filesystem. Temporary file with ".lock" extension won't be deleted.

All Realm instances must be closed before calling this method.

WARNING: For synchronized Realm, there is a chance that an internal Realm instance on the background thread is not closed even all the user controlled Realm instances are closed. This will result an IllegalStateException . See issue https://github.com/realm/realm-java/issues/5416 .

Parameters

Returns

false if the Realm file could not be deleted. Temporary files deletion failure won't impact the return value. All of the failing file deletions will be logged.

Throws

executeTransaction

public void executeTransaction (
Realm.Transaction transaction
)

Executes a given transaction on the Realm. beginTransaction() and commitTransaction() will be called automatically. If any exception is thrown during the transaction cancelTransaction() will be called instead of commitTransaction().

Calling this method from the UI thread will throw a RealmException . Doing so may result in a drop of frames or even ANRs. We recommend calling this method from a non-UI thread or using executeTransactionAsync(Transaction) instead.

Parameters

Throws

executeTransactionAsync

Similar to executeTransactionAsync(Transaction) , but also accepts an OnSuccess and OnError callbacks.

Parameters

  • transaction - io.realm.Realm.Transaction to execute.

  • onSuccess - callback invoked when the transaction succeeds.

  • onError - callback invoked when the transaction fails.

Returns

a RealmAsyncTask representing a cancellable task.

Throws

Similar to executeTransactionAsync(Transaction) , but also accepts an OnError callback.

Parameters

Returns

a RealmAsyncTask representing a cancellable task.

Throws

Similar to executeTransactionAsync(Transaction) , but also accepts an OnSuccess callback.

Parameters

Returns

a RealmAsyncTask representing a cancellable task.

Throws

Similar to executeTransaction(Transaction) but runs asynchronously on a worker thread.

Parameters

Returns

a RealmAsyncTask representing a cancellable task.

Throws

freeze

public Realm freeze ()

Returns a frozen snapshot of the current Realm. This Realm can be read and queried from any thread without throwing an IllegalStateException . A frozen Realm has its own lifecycle and can be closed by calling close(), but fully closing the Realm that spawned the frozen copy will also close the frozen Realm.

Frozen data can be queried as normal, but trying to mutate it in any way or attempting to register any listener will throw an IllegalStateException .

Note: Keeping a large number of Realms with different versions alive can have a negative impact on the filesize of the Realm. In order to avoid such a situation, it is possible to set RealmConfiguration.Builder.maxNumberOfActiveVersions(long) .

Returns

a frozen copy of this Realm.

Overrides

freeze in class BaseRealm

getApplicationContext

public static Context getApplicationContext ()

Get the application context used when initializing Realm with Realm.init(Context) or Realm.init(Context, String) .

Returns

the application context used when initializing Realm with Realm.init(Context) or Realm.init(Context, String) , or null if Realm has not been initialized yet.

getDefaultConfiguration

Returns the default configuration for getDefaultInstance() .

Returns

default configuration object or null if no default configuration is specified.

getDefaultInstance

public static Realm getDefaultInstance ()

Realm static constructor that returns the Realm instance defined by the io.realm.RealmConfiguration set by setDefaultConfiguration(RealmConfiguration)

Returns

an instance of the Realm class.

Throws

getDefaultModule

public static Object getDefaultModule ()

Returns the default Realm module. This module contains all Realm classes in the current project, but not those from library or project dependencies. Realm classes in these should be exposed using their own module.

Returns

the default Realm module or null if no default module exists.

Throws

Tip

See also:

getGlobalInstanceCount

public static int getGlobalInstanceCount (
RealmConfiguration configuration
)

Returns the current number of open Realm instances across all threads in current process that are using this configuration. This includes both dynamic and normal Realms.

Parameters

Returns

number of open Realm instances across all threads.

getInstance

public static Realm getInstance (
RealmConfiguration configuration
)

Realm static constructor that returns the Realm instance defined by provided io.realm.RealmConfiguration

Parameters

Returns

an instance of the Realm class

Throws

Tip

See also:

getInstanceAsync

public static RealmAsyncTask getInstanceAsync (
RealmConfiguration configuration,
Realm.Callback callback
)

The creation of the first Realm instance per RealmConfiguration in a process can take some time as all initialization code need to run at that point (setting up the Realm, validating schemas and creating initial data). This method places the initialization work in a background thread and deliver the Realm instance to the caller thread asynchronously after the initialization is finished.

Parameters

  • configuration - RealmConfiguration used to open the Realm.

  • callback - invoked to return the results.

Returns

a RealmAsyncTask representing a cancellable task.

Throws

Tip

See also:

getLocalInstanceCount

public static int getLocalInstanceCount (
RealmConfiguration configuration
)

Returns the current number of open Realm instances on the thread calling this method. This include both dynamic and normal Realms.

Parameters

Returns

number of open Realm instances on the caller thread.

getSchema

Returns the schema for this Realm. The schema is immutable. Any attempt to modify it will result in an UnsupportedOperationException .

The schema can only be modified using DynamicRealm.getSchema() or through an migration.

Returns

The RealmSchema for this Realm.

Overrides

getSchema in class BaseRealm

init

public static synchronized void init (
Context context,
String userAgent
)

Initializes the Realm library and creates a default configuration that is ready to use. It is required to call this method before interacting with any other of the Realm API's.A good place is in an android.app.Application subclass:

public class MyApplication extends Application {
  @Override
  public void onCreate() {
    super.onCreate();
    Realm.init(this, "MyApp/" + BuildConfig.VERSION_NAME);
  }
}

Remember to register it in the AndroidManifest.xml file:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="io.realm.example">
<application android:name=".MyApplication">
  // ...
</application>
</manifest>

Parameters

  • context - the Application Context.

  • userAgent - optional user defined string that will be sent to the Realm Object Server as part of a User-Agent header when a session is established. This setting will not be used by non-synchronized Realms.

Throws

Tip

See also:

public static synchronized void init (
Context context
)

Initializes the Realm library and creates a default configuration that is ready to use. It is required to call this method before interacting with any other of the Realm API's.A good place is in an android.app.Application subclass:

public class MyApplication extends Application {
  @Override
  public void onCreate() {
    super.onCreate();
    Realm.init(this);
  }
}

Remember to register it in the AndroidManifest.xml file:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="io.realm.example">
<application android:name=".MyApplication">
  // ...
</application>
</manifest>

Parameters

  • context - the Application Context.

Throws

Tip

See also:

insert

public void insert (
RealmModel object
)

Inserts an unmanaged RealmObject. This is generally faster than copyToRealm(RealmModel, ImportFlag...) since it doesn't return the inserted elements, and performs minimum allocations and checks. After being inserted any changes to the original object will not be persisted.

Please note:

  • We don't check if the provided objects are already managed or not, so inserting a managed object might duplicate it. Duplication will only happen if the object doesn't have a primary key. Objects with primary keys will never get duplicated.

  • We don't create (nor return) a managed RealmObject for each element

  • Copying an object will copy all field values. Any unset field in the object and child objects will be set to their default value if not provided

If you want the managed RealmObject returned, use copyToRealm(RealmModel, ImportFlag...) , otherwise if you have a large number of object this method is generally faster.

Parameters

  • object - RealmObjects to insert.

Throws

Inserts a list of an unmanaged RealmObjects. This is generally faster than copyToRealm(Iterable, ImportFlag...) since it doesn't return the inserted elements, and performs minimum allocations and checks. After being inserted any changes to the original objects will not be persisted.

Please note:

  • We don't check if the provided objects are already managed or not, so inserting a managed object might duplicate it. Duplication will only happen if the object doesn't have a primary key. Objects with primary keys will never get duplicated.

  • We don't create (nor return) a managed RealmObject for each element

  • Copying an object will copy all field values. Any unset field in the object and child objects will be set to their default value if not provided

If you want the managed RealmObject returned, use copyToRealm(Iterable, ImportFlag...) , otherwise if you have a large number of object this method is generally faster.

Parameters

  • objects - RealmObjects to insert.

Throws

  • IllegalStateException - if the corresponding Realm is closed, called from an incorrect thread or not in a transaction.

insertOrUpdate

public void insertOrUpdate (
RealmModel object
)

Inserts or updates an unmanaged RealmObject. This is generally faster than copyToRealmOrUpdate(RealmModel, ImportFlag...) since it doesn't return the inserted elements, and performs minimum allocations and checks. After being inserted any changes to the original object will not be persisted.

Please note:

  • We don't check if the provided objects are already managed or not, so inserting a managed object might duplicate it. Duplication will only happen if the object doesn't have a primary key. Objects with primary keys will never get duplicated.

  • We don't create (nor return) a managed RealmObject for each element

  • Copying an object will copy all field values. Any unset field in the object and child objects will be set to their default value if not provided

If you want the managed RealmObject returned, use copyToRealm(RealmModel, ImportFlag...) , otherwise if you have a large number of object this method is generally faster.

Parameters

  • object - RealmObjects to insert.

Throws

  • IllegalStateException - if the corresponding Realm is closed, called from an incorrect thread or not in a transaction.

Inserts or updates a list of unmanaged RealmObjects. This is generally faster than copyToRealmOrUpdate(Iterable, ImportFlag...) since it doesn't return the inserted elements, and performs minimum allocations and checks. After being inserted any changes to the original objects will not be persisted.

Please note:

  • We don't check if the provided objects are already managed or not, so inserting a managed object might duplicate it. Duplication will only happen if the object doesn't have a primary key. Objects with primary keys will never get duplicated.

  • We don't create (nor return) a managed RealmObject for each element

  • Copying an object will copy all field values. Any unset field in the object and child objects will be set to their default value if not provided

If you want the managed RealmObject returned, use copyToRealm(Iterable, ImportFlag...) , otherwise if you have a large number of object this method is generally faster.

Parameters

  • objects - RealmObjects to insert.

Throws

isEmpty

public boolean isEmpty ()

Checks if this io.realm.Realm contains any objects.

Returns

true if empty, @{code false} otherwise.

Overrides

isEmpty in class BaseRealm

migrateRealm

public static void migrateRealm (
RealmConfiguration configuration,
RealmMigration migration
)

Manually triggers a migration on a RealmMigration.

Parameters

  • configuration - the:ref:RealmConfiguration <io_realm_RealmConfiguration> .

  • migration - the RealmMigration to run on the Realm. This will override any migration set on the configuration.

Throws

public static void migrateRealm (
RealmConfiguration configuration
)

Manually triggers the migration associated with a given RealmConfiguration. If Realm is already at the latest version, nothing will happen.

Parameters

Throws

removeAllChangeListeners

Removes all user-defined change listeners.

Throws

Tip

See also:

removeChangeListener

Removes the specified change listener.

Parameters

  • listener - the change listener to be removed.

Throws

Tip

See also:

removeDefaultConfiguration

public static void removeDefaultConfiguration ()

Removes the current default configuration (if any). Any further calls to getDefaultInstance() will fail until a new default configuration has been set using setDefaultConfiguration(RealmConfiguration) .

setDefaultConfiguration

public static void setDefaultConfiguration (
RealmConfiguration configuration
)

Sets the io.realm.RealmConfiguration used when calling getDefaultInstance() .

Parameters

Throws

Tip

See also:

where

Returns a typed RealmQuery, which can be used to query for specific objects of this type

Parameters

  • clazz - the class of the object which is to be queried for.

Returns

a typed RealmQuery, which can be used to query for specific objects of this type.

Tip

See also:

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