io.realm

Enum ImportFlag

java.lang.Object

java.lang.Enum<ImportFlag>

io.realm.ImportFlag

All Implemented Interfaces:

Serializable, Comparable<ImportFlag>

public enum ImportFlag
extends Enum<ImportFlag>

This class describe how data is saved to Realm when saving whole objects.

See Also:

Realm.copyToRealm(RealmModel, ImportFlag...)

Enum Constant Summary

Enum Constants

Enum Constant and Description
CHECK_SAME_VALUES_BEFORE_SET With this flag enabled, fields will not be written to the Realm file if they contain the same value as the value already present in the Realm.

Method Summary

Modifier and Type	Method and Description
static ImportFlag	valueOf(String name) Returns the enum constant of this type with the specified name.
static ImportFlag[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

compareTo, equals, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

CHECK_SAME_VALUES_BEFORE_SET

public static final ImportFlag CHECK_SAME_VALUES_BEFORE_SET

With this flag enabled, fields will not be written to the Realm file if they contain the same value as the value already present in the Realm.

For local Realms this only has an impact on change listeners which will not report changes to those fields that was not written.

For synchronized Realms this also impacts the server, which will see improved performance as there is less changes to upload and merge into the server Realm.

It also impact how the server merges changes from different devices. Realm uses a last-write-wins approach when merging individual fields in an object, so if a field is not written it will be considered "older" than other fields modified.

E.g:

1. Server starts out with (Field A = 1, Field B = 1)
2. Device 1 writes (Field A = 2, Field B = 2).
3. Device 2 writes (Field A = 3, Field B = 1) but ignores (Field B = 1), because that is the value in the Realm file at this point.
4. Device 1 uploads its changes to the server making the server (Field A = 2, Field B = 2). Then Device 2 uploads its changes. Due to last-write-wins, the server version now becomes (Field A = 3, Field B = 2).

This is normally the desired behaviour as the final object is the merged result of the latest changes from both devices, however if all the fields in an object are considered an atomic unit, then this flag should not be set as it will ensure that all fields are set and thus have the same "age" when data are sent to the server.

See Also:

Docs on conflict resolution

Method Detail

values

public static ImportFlag[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (ImportFlag c : ImportFlag.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static ImportFlag valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null