io.realm

Class Realm

java.lang.Object

io.realm.Realm

public class Realm
extends java.lang.Object

The Realm class is the storage and transactional manager of your object persistent store. Objects are created. Objects within a Realm can be queried and read at any time. Creating, modifying, and deleting objects must be done through transactions.

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

If auto-refresh is set the instance of the Realm will be automatically updated when another instance commits a change (create, modify or delete an object). This feature requires the Realm instance to be residing in a thread attached to a Looper (the main thread has a Looper by default)

For normal threads Android provides a utility class that can be used like this:

 HandlerThread thread = new HandlerThread("MyThread") {

Field Summary

Fields

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

Method Summary

Methods

Modifier and Type	Method and Description
void	addChangeListener(RealmChangeListener listener) Add a change listener to the Realm
<E extends RealmObject> RealmResults<E>	allObjects(java.lang.Class<E> clazz) Get all objects of a specific Class
void	beginTransaction() Starts a write transaction, this must be closed with commitTransaction() or aborted by @{link io.realm.Realm#cancelTransaction()}.
void	cancelTransaction() Revert all writes (created, updated, or deleted objects) made in the current write transaction and end the transaction.
void	clear(java.lang.Class<?> classSpec) Remove all objects of the specified class.
void	commitTransaction() All changes since @{link io.realm.Realm#beginTransaction()} are persisted to disk and the realm reverts back to being read-only.
static Realm	create(java.io.File writableFolder, java.lang.String filename, byte[] key, boolean autoRefresh) Realm static constructor
<E extends RealmObject> E	createObject(java.lang.Class<E> clazz) Instantiates and adds a new object to the realm
static boolean	deleteRealmFile(android.content.Context context) Delete the Realm file from the filesystem for the default Realm (named "default.realm").
static boolean	deleteRealmFile(android.content.Context context, java.lang.String fileName) Delete the Realm file from the filesystem for a custom named Realm.
protected void	finalize()
static Realm	getInstance(android.content.Context context) Realm static constructor for the default realm "default.realm" It sets auto-refresh on
static Realm	getInstance(android.content.Context context, boolean autoRefresh) Realm static constructor for the default realm "default.realm"
static Realm	getInstance(android.content.Context context, byte[] key) Realm static constructor It sets auto-refresh on
static Realm	getInstance(android.content.Context context, byte[] key, boolean autoRefresh) Realm static constructor
static Realm	getInstance(android.content.Context context, java.lang.String fileName) Realm static constructor It sets auto-refresh on
static Realm	getInstance(android.content.Context context, java.lang.String fileName, boolean autoRefresh) Realm static constructor
static Realm	getInstance(android.content.Context context, java.lang.String fileName, byte[] key, boolean autoRefresh) Realm static constructor
static Realm	getInstance(java.io.File writableFolder, byte[] key, boolean autoRefresh) Realm static constructor
Table	getTable(java.lang.Class<?> clazz)
boolean	isAutoRefresh() Retrieve the auto-refresh status of the Realm instance
static void	migrateRealmAtPath(java.lang.String realmPath, byte[] key, RealmMigration migration)
static void	migrateRealmAtPath(java.lang.String realmPath, byte[] key, RealmMigration migration, boolean autoUpdate)
static void	migrateRealmAtPath(java.lang.String realmPath, RealmMigration migration)
static void	migrateRealmAtPath(java.lang.String realmPath, RealmMigration migration, boolean autoRefresh)
void	refresh() Refresh the Realm instance and all the RealmResults and RealmObjects instances coming from it
void	removeAllChangeListeners() Remove all user-defined change listeners
void	removeChangeListener(RealmChangeListener listener) Remove the specified change listener
void	setAutoRefresh(boolean autoRefresh) Set the auto-refresh status of the Realm instance Auto-refresh is a feature to allows to automatically update the current realm instance and all its derived objects (RealmResults and RealmObjects instances) when a commit is performed on a Realm acting on the same file in another thread.
<E extends RealmObject> RealmQuery<E>	where(java.lang.Class<E> clazz) Returns a typed RealmQuery, which can be used to query for specific objects of this type

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_REALM_NAME

public static final java.lang.String DEFAULT_REALM_NAME

See Also:

Constant Field Values

Method Detail

finalize

protected void finalize()
                 throws java.lang.Throwable

Overrides:

finalize in class java.lang.Object

Throws:

java.lang.Throwable

isAutoRefresh

public boolean isAutoRefresh()

Retrieve the auto-refresh status of the Realm instance

Returns:

the auto-refresh status

setAutoRefresh

public void setAutoRefresh(boolean autoRefresh)

Set the auto-refresh status of the Realm instance Auto-refresh is a feature to allows to automatically update the current realm instance and all its derived objects (RealmResults and RealmObjects instances) when a commit is performed on a Realm acting on the same file in another thread. This feature is only available if the realm instance lives is a Looper enabled thread.

Parameters:

autoRefresh - true will turn auto-refresh on, false will turn it off

Throws:

java.lang.IllegalStateException - if trying to enable auto-refresh in a thread without Looper

getTable

public Table getTable(java.lang.Class<?> clazz)

getInstance

public static Realm getInstance(android.content.Context context)

Realm static constructor for the default realm "default.realm" It sets auto-refresh on

Parameters:

context - an Android Context

Returns:

an instance of the Realm class

Throws:

RealmMigrationNeededException - The model classes have been changed and the Realm must be migrated

RealmIOException - Error when accessing underlying file

java.lang.IllegalStateException - The Realm is being instantiated in a Thread without a Looper

RealmException - Other errors

getInstance

public static Realm getInstance(android.content.Context context,
                boolean autoRefresh)

Realm static constructor for the default realm "default.realm"

Parameters:

context - an Android context

autoRefresh - whether the Realm object and its derived objects (RealmResults and RealmObjects) should be automatically refreshed with the event loop (requires to be in a thread with a Looper)

Returns:

an instance of the Realm class

Throws:

RealmMigrationNeededException - The model classes have been changed and the Realm must be migrated

RealmIOException - Error when accessing underlying file

java.lang.IllegalStateException - The Realm is being instantiated with auto-refresh in a Thread without a Looper

RealmException - Other errors

getInstance

public static Realm getInstance(android.content.Context context,
                java.lang.String fileName)

Realm static constructor It sets auto-refresh on

Parameters:

context - an Android Context

fileName - the name of the file to save the Realm to

Returns:

an instance of the Realm class

Throws:

RealmMigrationNeededException - The model classes have been changed and the Realm must be migrated

RealmIOException - Error when accessing underlying file

java.lang.IllegalStateException - The Realm is being instantiated in a Thread without a Looper

RealmException - Other errors

getInstance

public static Realm getInstance(android.content.Context context,
                java.lang.String fileName,
                boolean autoRefresh)

Realm static constructor

Parameters:

context - an Android context

fileName - the name of the file to save the Realm to

autoRefresh - whether the Realm object and its derived objects (RealmResults and RealmObjects) should be automatically refreshed with the event loop (requires to be in a thread with a Looper)

Returns:

an instance of the Realm class

Throws:

RealmMigrationNeededException - The model classes have been changed and the Realm must be migrated

RealmIOException - Error when accessing underlying file

java.lang.IllegalStateException - The Realm is being instantiated with auto-refresh in a Thread without a Looper

RealmException - Other errors

getInstance

public static Realm getInstance(android.content.Context context,
                byte[] key,
                boolean autoRefresh)

Realm static constructor

Parameters:

context - an Android context

key - a 32-byte encryption key

autoRefresh - whether the Realm object and its derived objects (RealmResults and RealmObjects) should be automatically refreshed with the event loop (requires to be in a thread with a Looper)

Returns:

an instance of the Realm class

Throws:

RealmMigrationNeededException - The model classes have been changed and the Realm must be migrated

RealmIOException - Error when accessing underlying file

java.lang.IllegalStateException - The Realm is being instantiated with auto-refresh in a Thread without a Looper

RealmException - Other errors

getInstance

public static Realm getInstance(android.content.Context context,
                byte[] key)

Realm static constructor It sets auto-refresh on

Parameters:

context - an Android Context

key - a 32-byte encryption key

Returns:

an instance of the Realm class

Throws:

RealmMigrationNeededException - The model classes have been changed and the Realm must be migrated

RealmIOException - Error when accessing underlying file

java.lang.IllegalStateException - The Realm is being instantiated in a Thread without a Looper

RealmException - Other errors

getInstance

public static Realm getInstance(android.content.Context context,
                java.lang.String fileName,
                byte[] key,
                boolean autoRefresh)

Realm static constructor

Parameters:

context - an Android Context

fileName - the name of the file to save the Realm to

key - a 32-byte encryption key

autoRefresh - whether the Realm object and its derived objects (RealmResults and RealmObjects) should be automatically refreshed with the event loop (requires to be in a thread with a Looper)

Returns:

an instance of the Realm class

Throws:

RealmMigrationNeededException - The model classes have been changed and the Realm must be migrated

RealmIOException - Error when accessing underlying file

java.lang.IllegalStateException - The Realm is being instantiated in a Thread without a Looper

RealmException - Other errors

getInstance

public static Realm getInstance(java.io.File writableFolder,
                byte[] key,
                boolean autoRefresh)

Realm static constructor

Parameters:

writableFolder - absolute path to a writable directory

key - a 32-byte encryption key

autoRefresh - whether the Realm object and its derived objects (RealmResults and RealmObjects) should be automatically refreshed with the event loop (requires to be in a thread with a Looper)

Returns:

an instance of the Realm class

Throws:

RealmMigrationNeededException - The model classes have been changed and the Realm must be migrated

RealmIOException - Error when accessing underlying file

java.lang.IllegalStateException - The Realm is being instantiated in a Thread without a Looper

RealmException - Other errors

create

public static Realm create(java.io.File writableFolder,
           java.lang.String filename,
           byte[] key,
           boolean autoRefresh)

Realm static constructor

Parameters:

writableFolder - absolute path to a writable directory

filename - the name of the file to save the Realm to

key - a 32-byte encryption key

autoRefresh - whether the Realm object and its derived objects (RealmResults and RealmObjects) should be automatically refreshed with the event loop (requires to be in a thread with a Looper)

Returns:

an instance of the Realm class

Throws:

RealmMigrationNeededException - The model classes have been changed and the Realm must be migrated

RealmIOException - Error when accessing underlying file

java.lang.IllegalStateException - The Realm is being instantiated in a Thread without a Looper

RealmException - Other errors

createObject

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

Instantiates and adds a new object to the realm

Parameters:

clazz - The Class of the object to create

Returns:

The new object

Throws:

RealmException - An object could not be created

where

public <E extends RealmObject> RealmQuery<E> where(java.lang.Class<E> clazz)

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

Throws:

java.lang.RuntimeException - Any other error

See Also:

RealmQuery

allObjects

public <E extends RealmObject> RealmResults<E> allObjects(java.lang.Class<E> clazz)

Get all objects of a specific Class

Parameters:

clazz - the Class to get objects of

Returns:

A RealmResult list containing the objects

Throws:

java.lang.RuntimeException - Any other error

See Also:

RealmResults

addChangeListener

public void addChangeListener(RealmChangeListener listener)

Add a change listener to the Realm

Parameters:

listener - the change listener

See Also:

RealmChangeListener

removeChangeListener

public void removeChangeListener(RealmChangeListener listener)

Remove the specified change listener

Parameters:

listener - the change listener to be removed

See Also:

RealmChangeListener

removeAllChangeListeners

public void removeAllChangeListeners()

Remove all user-defined change listeners

See Also:

RealmChangeListener

refresh

public void refresh()

Refresh the Realm instance and all the RealmResults and RealmObjects instances coming from it

beginTransaction

public void beginTransaction()

Starts a write transaction, this must be closed with commitTransaction() or aborted by @{link io.realm.Realm#cancelTransaction()}. Write transactions are used to atomically create, update and delete objects within a realm.
Before beginning the write transaction, @{link io.realm.Realm#beginTransaction()} updates the realm in the case of pending updates from other threads.
Notice: it is not possible to nest write transactions. If you start a write transaction within a write transaction an exception is thrown.

Throws:

java.lang.IllegalStateException - If already in a write transaction.

commitTransaction

public void commitTransaction()

All changes since @{link io.realm.Realm#beginTransaction()} are persisted to disk and the realm reverts back to being read-only. An event is sent to notify all other realm instances that a change has occurred. When the event is received, the other realms will get their objects and @{link io.realm.RealmResults} updated to reflect the changes from this commit.

Throws:

java.lang.IllegalStateException - If the write transaction is in an invalid state.

cancelTransaction

public void cancelTransaction()

Revert all writes (created, updated, or deleted objects) made in the current write transaction and end the transaction.
The realm reverts back to read-only.
Calling this when not in a write transaction will throw an exception.

Throws:

java.lang.IllegalStateException - If the write transaction is an invalid state or not in a write transaction.

clear

public void clear(java.lang.Class<?> classSpec)

Remove all objects of the specified class.

Parameters:

classSpec - The class which objects should be removed

Throws:

java.lang.RuntimeException - Any other error

migrateRealmAtPath

public static void migrateRealmAtPath(java.lang.String realmPath,
                      RealmMigration migration)

migrateRealmAtPath

public static void migrateRealmAtPath(java.lang.String realmPath,
                      byte[] key,
                      RealmMigration migration)

migrateRealmAtPath

public static void migrateRealmAtPath(java.lang.String realmPath,
                      RealmMigration migration,
                      boolean autoRefresh)

migrateRealmAtPath

public static void migrateRealmAtPath(java.lang.String realmPath,
                      byte[] key,
                      RealmMigration migration,
                      boolean autoUpdate)

deleteRealmFile

public static boolean deleteRealmFile(android.content.Context context)

Delete the Realm file from the filesystem for the default Realm (named "default.realm"). The realm must be unused and closed before calling this method. WARNING: Your Realm must not be open (typically when your app launch).

Parameters:

context - an Android context.

Returns:

false if a file could not be deleted. The failing file will be logged.

See Also:

clear(Class)

deleteRealmFile

public static boolean deleteRealmFile(android.content.Context context,
                      java.lang.String fileName)

Delete the Realm file from the filesystem for a custom named Realm. The realm must be unused and closed before calling this method.

Parameters:

context - an Android @{Context.

fileName - the name of the custom Realm (i.e. "myCustomRealm.realm").

Returns:

false if a file could not be deleted. The failing file will be logged.