Package org.infinispan.xsite.spi

Enum XSiteMergePolicy

java.lang.Object

java.lang.Enum<XSiteMergePolicy>

org.infinispan.xsite.spi.XSiteMergePolicy

All Implemented Interfaces:

Serializable, Comparable<XSiteMergePolicy>, XSiteEntryMergePolicy<Object,Object>

public enum XSiteMergePolicy
extends Enum<XSiteMergePolicy>
implements XSiteEntryMergePolicy<Object,Object>

An alias with the provided implementation of XSiteEntryMergePolicy.

To be used in SitesConfigurationBuilder.mergePolicy(XSiteEntryMergePolicy)

Since:

12.0

Author:

Pedro Ruivo

See Also:

XSiteEntryMergePolicy, PreferNonNullXSiteEntryMergePolicy, PreferNullXSiteEntryMergePolicy, AlwaysRemoveXSiteEntryMergePolicy, DefaultXSiteEntryMergePolicy

Enum Constant Summary

Enum Constants

Enum Constant	Description
ALWAYS_REMOVE	Always remove the key if there is a conflict.
DEFAULT	The default implementation chooses the entry with the lower lexicographically site name (SiteEntry.getSiteName()).
PREFER_NON_NULL	Chooses the non-null value if available (write/remove conflict, write wins), otherwise uses the DEFAULT.
PREFER_NULL	Chooses the null value if available (write/remove conflict, remove wins), otherwise uses the DEFAULT.

Method Summary

Modifier and Type	Method	Description
static <K,V> XSiteMergePolicy	fromInstance(XSiteEntryMergePolicy<K,V> r2)
static XSiteMergePolicy	fromString(String str)
abstract <K,V> XSiteEntryMergePolicy<K,V>	getInstance()
static <T,U> XSiteEntryMergePolicy<T,U>	instanceFromString(String value, ClassLoader classLoader)
CompletionStage<SiteEntry<Object>>	merge(Object key, SiteEntry<Object> localEntry, SiteEntry<Object> remoteEntry)	Resolves conflicts for asynchronous cross-site replication.
static XSiteMergePolicy	valueOf(String name)	Returns the enum constant of this type with the specified name.
static XSiteMergePolicy[]	values()	Returns an array containing the constants of this enum type, in the order they are declared.

Enum Constant Detail

PREFER_NON_NULL

public static final XSiteMergePolicy PREFER_NON_NULL

Chooses the non-null value if available (write/remove conflict, write wins), otherwise uses the DEFAULT.

See Also:

PreferNonNullXSiteEntryMergePolicy

PREFER_NULL

public static final XSiteMergePolicy PREFER_NULL

Chooses the null value if available (write/remove conflict, remove wins), otherwise uses the DEFAULT.

See Also:

PreferNullXSiteEntryMergePolicy

ALWAYS_REMOVE

public static final XSiteMergePolicy ALWAYS_REMOVE

Always remove the key if there is a conflict.

See Also:

AlwaysRemoveXSiteEntryMergePolicy

DEFAULT

public static final XSiteMergePolicy DEFAULT

The default implementation chooses the entry with the lower lexicographically site name (SiteEntry.getSiteName()).

See Also:

DefaultXSiteEntryMergePolicy

Method Detail

values

public static XSiteMergePolicy[] 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 (XSiteMergePolicy c : XSiteMergePolicy.values())
    System.out.println(c);

Returns:

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

valueOf

public static XSiteMergePolicy 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

fromString

public static XSiteMergePolicy fromString(String str)

fromInstance

public static <K,V> XSiteMergePolicy fromInstance(XSiteEntryMergePolicy<K,V> r2)

instanceFromString

public static <T,U> XSiteEntryMergePolicy<T,U> instanceFromString(String value,
                                                                              ClassLoader classLoader)

merge

public CompletionStage<SiteEntry<Object>> merge(Object key,
                                                SiteEntry<Object> localEntry,
                                                SiteEntry<Object> remoteEntry)

Description copied from interface: XSiteEntryMergePolicy

Resolves conflicts for asynchronous cross-site replication.

When a conflict is detected (concurrent updates on the same key in different sites), this method is invoked with the local data and the remote site's data (SiteEntry). It includes the value and the Metadata associated.

The value and the Metadata may be null. If that is the case, it means the key doesn't exist (for localEntry) or it is a remove operation (for remoteEntry).

The returned SiteEntry must be equal independent of the order of the arguments (i.e. resolve(k, s1, s2).equals(resolve(k, s2, s1))) otherwise your date may be corrupted. It is allowed to return one of the arguments (localEntry or remoteEntry) and to create a new SiteEntry with a new value.

Note: if the return SiteEntry.getValue() is null, Infinispan will interpret it to remove the key.

Note2: This method shouldn't block (I/O or locks). If it needs to block, use a different thread and complete the CompletionStage with the result. We recommend using BlockingManager.supplyBlocking(Supplier, Object).

Specified by:

merge in interface XSiteEntryMergePolicy<Object,Object>

Parameters:

key - The key that was updated concurrently.

localEntry - The local value and Metadata stored.

remoteEntry - The remote value and Metadata received.

Returns:

A CompletionStage with the SiteEntry.

getInstance

public abstract <K,V> XSiteEntryMergePolicy<K,V> getInstance()