Package org.apache.accumulo.server.conf.store

Interface PropStore

All Known Implementing Classes:

ZooPropStore

public interface PropStore

Method Summary

Modifier and Type	Method	Description
void	create(PropStoreKey<?> propStoreKey, Map<String,String> props)	Create an initial entry for the PropCacheId.
void	delete(PropStoreKey<?> propStoreKey)	Delete the store node from the underlying store.
boolean	exists(PropStoreKey<?> propStoreKey)	Test that a node for properties exists without throwing a KeeperException.
@NonNull VersionedProperties	get(PropStoreKey<?> propCacheId)
PropCache	getCache()
@Nullable VersionedProperties	getIfCached(PropStoreKey<?> propStoreKey)
void	putAll(PropStoreKey<?> propStoreKey, Map<String,String> props)	Adds or updates current properties.
void	registerAsListener(PropStoreKey<?> propStoreKey, PropChangeListener listener)	External processes can register for notifications if the properties change.
void	removeProperties(PropStoreKey<?> propStoreKey, Collection<String> keys)	Deletes individual properties specified by the set of keys.
void	replaceAll(PropStoreKey<?> propStoreKey, long version, Map<String,String> props)	Replaces all current properties with map provided.
boolean	validateDataVersion(PropStoreKey<?> storeKey, long expectedVersion)	Compare the stored data version with the expected version.

Method Detail

exists

boolean exists(PropStoreKey<?> propStoreKey)

Test that a node for properties exists without throwing a KeeperException.

Parameters:

propStoreKey - the prop cache key

Returns:

true if the property node exists, false otherwise.

Throws:

IllegalStateException - if the check fails due to interrupt.

create

void create(PropStoreKey<?> propStoreKey,
            Map<String,String> props)

Create an initial entry for the PropCacheId. If properties already exist, they are not modified.

Parameters:

propStoreKey - the prop cache key

props - a map of property k,v pairs

Throws:

IllegalStateException - if the updates fails because of an underlying store exception

get

@NonNull VersionedProperties get(PropStoreKey<?> propCacheId)

Parameters:

propCacheId - the prop cache key

Returns:

The versioned properties.

Throws:

IllegalStateException - if the updates fails because of an underlying store exception or if the properties do not exist for the propCacheId

putAll

void putAll(PropStoreKey<?> propStoreKey,
            Map<String,String> props)

Adds or updates current properties. If the property currently exists it is overwritten, otherwise it is added.

Parameters:

propStoreKey - the prop cache key

props - a map of property k,v pairs

Throws:

IllegalStateException - if the values cannot be written or if an underlying store exception occurs.

replaceAll

void replaceAll(PropStoreKey<?> propStoreKey,
                long version,
                Map<String,String> props)
         throws ConcurrentModificationException

Replaces all current properties with map provided. If a property is not included in the new map, the property will not be set.

Parameters:

propStoreKey - the prop cache key

version - the version of the properties

props - a map of property k,v pairs

Throws:

IllegalStateException - if the values cannot be written or if an underlying store exception occurs.

ConcurrentModificationException - if the properties changed since reading and can not be modified

delete

void delete(PropStoreKey<?> propStoreKey)

Delete the store node from the underlying store.

Parameters:

propStoreKey - the prop cache key

Throws:

IllegalStateException - if the updates fails because of an underlying store exception

removeProperties

void removeProperties(PropStoreKey<?> propStoreKey,
                      Collection<String> keys)

Deletes individual properties specified by the set of keys.

Parameters:

propStoreKey - the prop cache key

keys - a set of keys.

Throws:

IllegalStateException - if the values cannot be deleted or if an underlying store exception occurs.

registerAsListener

void registerAsListener(PropStoreKey<?> propStoreKey,
                        PropChangeListener listener)

External processes can register for notifications if the properties change. Normally processes can read from the store and always receive the current snapshot of the latest values. However, it the process wants to take an active action on change detections, then they can register and receive notifications.

Implementation detail - the notification occurs on a separate thread from the underlying store, but listeners should not perform lengthy operations on the notification to prevent delaying other listeners from receive timely notification of the changes detected.

Parameters:

propStoreKey - the prop cache key

listener - a listener

getCache

PropCache getCache()

getIfCached

@Nullable VersionedProperties getIfCached(PropStoreKey<?> propStoreKey)

validateDataVersion

boolean validateDataVersion(PropStoreKey<?> storeKey,
                            long expectedVersion)

Compare the stored data version with the expected version. Notifies subscribers of the change detection.

Parameters:

storeKey - specifies key for backend store

expectedVersion - the expected data version

Returns:

true if the stored version matches the provided expected version.