Package org.apache.drill.exec.store.sys.store

Class VersionedDelegatingStore<V>

java.lang.Object

org.apache.drill.exec.store.sys.store.VersionedDelegatingStore<V>

Type Parameters:

V - store value type

All Implemented Interfaces:

AutoCloseable, Store<V>, VersionedPersistentStore<V>

public class VersionedDelegatingStore<V>
extends Object
implements VersionedPersistentStore<V>

Versioned store that delegates operations to PersistentStore and keeps versioning, incrementing version each time write / delete operation is triggered. Once created initial version is 0. Can be used only for local versioning, not distributed.

Constructor Summary

Constructors

Constructor	Description
VersionedDelegatingStore(PersistentStore<V> store)

Method Summary

Modifier and Type	Method	Description
void	close()
boolean	contains(String key, DataChangeVersion dataChangeVersion)	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, DataChangeVersion dataChangeVersion)	Returns the value for the given key if exists, null otherwise.
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, DataChangeVersion dataChangeVersion)	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 class java.lang.Object

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

Constructor Details

VersionedDelegatingStore

public VersionedDelegatingStore(PersistentStore<V> store)

Method Details

getMode

public PersistentStoreMode getMode()

Description copied from interface: Store

Returns storage mode of this store.

Specified by:

getMode in interface Store<V>

delete

public void delete(String key)

Description copied from interface: Store

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

Specified by:

delete in interface Store<V>

Parameters:

key - lookup key

contains

public boolean contains(String key,
 DataChangeVersion dataChangeVersion)

Description copied from interface: VersionedPersistentStore

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

Specified by:

contains in interface VersionedPersistentStore<V>

Parameters:

key - lookup key

dataChangeVersion - version holder

Returns:

true if store contains lookup key, false otherwise

get

public V get(String key,
 DataChangeVersion dataChangeVersion)

Description copied from interface: VersionedPersistentStore

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

Specified by:

get in interface VersionedPersistentStore<V>

Parameters:

key - lookup key

dataChangeVersion - version holder

put

public void put(String key,
 V value,
 DataChangeVersion dataChangeVersion)

Description copied from interface: VersionedPersistentStore

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.

Specified by:

put in interface VersionedPersistentStore<V>

Parameters:

key - lookup key

value - value to store

dataChangeVersion - version holder

putIfAbsent

public boolean putIfAbsent(String key,
 V value)

Description copied from interface: Store

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

Specified by:

putIfAbsent in interface Store<V>

Parameters:

key - lookup key

value - value to store

Returns:

true if put takes place, false otherwise.

getRange

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

Description copied from interface: Store

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

Specified by:

getRange in interface Store<V>

Parameters:

skip - number of records to skip from beginning

take - max number of records to return

close

public void close()
           throws Exception

Specified by:

close in interface AutoCloseable

Throws:

Exception