org.apache.drill.exec.store.sys

Interface PersistentStore<V>

Type Parameters:

V - value type

All Superinterfaces:

AutoCloseable

All Known Implementing Classes:

BasePersistentStore, InMemoryStore, LocalPersistentStore, NoWriteLocalStore, ZookeeperPersistentStore

public interface PersistentStore<V>
extends AutoCloseable

An abstraction used to store and retrieve instances of given value type.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	contains(String key) Checks if lookup key is present in store.
boolean	contains(String key, DataChangeVersion version) Checks if lookup key is present in store.
void	delete(String key) Removes the value corresponding to the given key if exists, nothing happens otherwise.
V	get(String key) Returns the value for the given key if exists, null otherwise.
V	get(String key, DataChangeVersion version) Returns the value for the given key if exists, null otherwise.
Iterator<Map.Entry<String,V>>	getAll() Returns an iterator of entries.
PersistentStoreMode	getMode() Returns storage mode of this store.
Iterator<Map.Entry<String,V>>	getRange(int skip, int take) Returns an iterator of desired number of entries offsetting by the skip value.
void	put(String key, V value) Stores the (key, value) tuple in the store.
void	put(String key, V value, DataChangeVersion version) Stores the (key, value) tuple in the store.
boolean	putIfAbsent(String key, V value) Stores the (key, value) tuple in the store only if it does not exists.

Methods inherited from interface java.lang.AutoCloseable

close

Method Detail

getMode

PersistentStoreMode getMode()

Returns storage mode of this store.

contains

boolean contains(String key)

Checks if lookup key is present in store.

Parameters:

key - lookup key

Returns:

true if store contains lookup key, false otherwise

contains

boolean contains(String key,
               DataChangeVersion version)

Checks if lookup key is present in store. Sets data change version number.

Parameters:

key - lookup key

version - version holder

Returns:

true if store contains lookup key, false otherwise

get

V get(String key)

Returns the value for the given key if exists, null otherwise.

Parameters:

key - lookup key

get

V get(String key,
    DataChangeVersion version)

Returns the value for the given key if exists, null otherwise. Sets data change version number.

Parameters:

key - lookup key

version - version holder

put

void put(String key,
       V value)

Stores the (key, value) tuple in the store. Lifetime of the tuple depends upon store mode.

Parameters:

key - lookup key

value - value to store

put

void put(String key,
       V value,
       DataChangeVersion version)

Stores the (key, value) tuple in the store. If tuple already exits, stores it only if versions match, otherwise throws VersionMismatchException Lifetime of the tuple depends upon store mode.

Parameters:

key - lookup key

value - value to store

version - version holder

delete

void delete(String key)

Removes the value corresponding to the given key if exists, nothing happens otherwise.

Parameters:

key - lookup key

putIfAbsent

boolean putIfAbsent(String key,
                  V value)

Stores the (key, value) tuple in the store only if it does not exists.

Parameters:

key - lookup key

value - value to store

Returns:

true if put takes place, false otherwise.

getRange

Iterator<Map.Entry<String,V>> getRange(int skip,
                                     int take)

Returns an iterator of desired number of entries offsetting by the skip value.

Parameters:

skip - number of records to skip from beginning

take - max number of records to return

getAll

Iterator<Map.Entry<String,V>> getAll()

Returns an iterator of entries.