Package org.opends.server.extensions

Class EntityTagVirtualAttributeProvider

java.lang.Object

org.opends.server.api.VirtualAttributeProvider<EntityTagVirtualAttributeCfg>

org.opends.server.extensions.EntityTagVirtualAttributeProvider

All Implemented Interfaces:

ConfigurationChangeListener<EntityTagVirtualAttributeCfg>

public final class EntityTagVirtualAttributeProvider
extends VirtualAttributeProvider<EntityTagVirtualAttributeCfg>
implements ConfigurationChangeListener<EntityTagVirtualAttributeCfg>

This class implements a virtual attribute provider which ensures that all entries contain an "entity tag" or "Etag" as defined in section 3.11 of RFC 2616.

The entity tag may be used by clients, in conjunction with the assertion control, for optimistic concurrency control, as a way to help prevent simultaneous updates of an entry from conflicting with each other.

Note: etags cannot be searched since there is no way to determine which entry is associated with a particular ETag.

Constructor Summary

Constructors

Constructor	Description
EntityTagVirtualAttributeProvider()

Method Summary

Modifier and Type	Method	Description
ConfigChangeResult	applyConfigurationChange(EntityTagVirtualAttributeCfg configuration)	Applies the configuration changes to this change listener.
void	finalizeVirtualAttributeProvider()	Performs any finalization that may be necessary whenever this virtual attribute provider is taken out of service.
Attribute	getAttribute(Entry entry, AttributeDescription attributeDescription)	Generates an unmodifiable attribute with the values for the provided entry.
void	initializeVirtualAttributeProvider(EntityTagVirtualAttributeCfg configuration)	Initializes this virtual attribute based on the information in the provided configuration entry.
boolean	isConfigurationChangeAcceptable(EntityTagVirtualAttributeCfg configuration, List<LocalizableMessage> unacceptableReasons)	Indicates whether the proposed change to the configuration is acceptable to this change listener.
boolean	isMultiValued()	Indicates whether this virtual attribute provider may generate multiple values.

Methods inherited from class org.opends.server.api.VirtualAttributeProvider

getServerContext, initializeVirtualAttributeProvider, isConfigurationAcceptable, isSearchable, processSearch

Methods inherited from class java.lang.Object

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

Constructor Detail

EntityTagVirtualAttributeProvider

public EntityTagVirtualAttributeProvider()

Method Detail

applyConfigurationChange

public ConfigChangeResult applyConfigurationChange(EntityTagVirtualAttributeCfg configuration)

Description copied from interface: ConfigurationChangeListener

Applies the configuration changes to this change listener.

Specified by:

applyConfigurationChange in interface ConfigurationChangeListener<EntityTagVirtualAttributeCfg>

Parameters:

configuration - The new configuration containing the changes.

Returns:

Returns information about the result of changing the configuration.

finalizeVirtualAttributeProvider

public void finalizeVirtualAttributeProvider()

Description copied from class: VirtualAttributeProvider

Performs any finalization that may be necessary whenever this virtual attribute provider is taken out of service.

Overrides:

finalizeVirtualAttributeProvider in class VirtualAttributeProvider<EntityTagVirtualAttributeCfg>

initializeVirtualAttributeProvider

public void initializeVirtualAttributeProvider(EntityTagVirtualAttributeCfg configuration)

Description copied from class: VirtualAttributeProvider

Initializes this virtual attribute based on the information in the provided configuration entry.

Overrides:

initializeVirtualAttributeProvider in class VirtualAttributeProvider<EntityTagVirtualAttributeCfg>

Parameters:

configuration - The configuration to use to initialize this virtual attribute provider.

isConfigurationChangeAcceptable

public boolean isConfigurationChangeAcceptable(EntityTagVirtualAttributeCfg configuration,
                                               List<LocalizableMessage> unacceptableReasons)

Description copied from interface: ConfigurationChangeListener

Indicates whether the proposed change to the configuration is acceptable to this change listener.

Specified by:

isConfigurationChangeAcceptable in interface ConfigurationChangeListener<EntityTagVirtualAttributeCfg>

Parameters:

configuration - The new configuration containing the changes.

unacceptableReasons - A list that can be used to hold messages about why the provided configuration is not acceptable.

Returns:

Returns true if the proposed change is acceptable, or false if it is not.

isMultiValued

public boolean isMultiValued()

Description copied from class: VirtualAttributeProvider

Indicates whether this virtual attribute provider may generate multiple values.

Specified by:

isMultiValued in class VirtualAttributeProvider<EntityTagVirtualAttributeCfg>

Returns:

true if this virtual attribute provider may generate multiple values, or false if not.

getAttribute

public Attribute getAttribute(Entry entry,
                              AttributeDescription attributeDescription)

Description copied from class: VirtualAttributeProvider

Generates an unmodifiable attribute with the values for the provided entry.

Specified by:

getAttribute in class VirtualAttributeProvider<EntityTagVirtualAttributeCfg>

Parameters:

entry - The entry for which the values are to be generated.

attributeDescription - the attribute description corresponding to this virtual attribute

Returns:

The unmodifiable attribute with the values generated for the provided entry. It may be empty, but it must not be null.