cern.entwined

Class TransactionalMultimap<K,V>

java.lang.Object

cern.entwined.SemiPersistent<TransactionalMultimap<K,V>>

cern.entwined.TransactionalMultimap<K,V>

All Implemented Interfaces:

OpaqueMultimap<K,V>

public class TransactionalMultimap<K,V>
extends SemiPersistent<TransactionalMultimap<K,V>>
implements OpaqueMultimap<K,V>

The opaque (impossible to query for all the items or get the size of the collection) transactional multimap implementation.

Author:

Ivan Koblik

Constructor Summary

Constructors

Constructor and Description
TransactionalMultimap() Constructs a new empty TransactionalMultimap.

Method Summary

Methods

Modifier and Type	Method and Description
protected TransactionalMultimap<K,V>	cleanCopy() Creates a new transactional entity from the current one discarding all the local changes.
void	clear() Removes all of the mappings from this map (optional operation).
TransactionalMultimap<K,V>	commit(TransactionalMultimap<K,V> globalState)
boolean	containsKey(K key) Returns true if this map contains a mapping for the specified key.
protected TransactionalMultimap<K,V>	dirtyCopy() Copies references to the source data along with local changes and read/write logs.
Set<V>	get(K key) Delegates to TransactionalMap.get(Object) replacing the returned null value with an empty set.
boolean	isEmpty() Delegates to TransactionalMap.isEmpty().
Set<K>	keySet() Delegates to TransactionalMap.keySet().
Set<V>	put(K key, V value) Adds the value to the entry with the given key.
Set<V>	putAll(K key, Collection<V> values) Puts all the values in the collection with the given key.
void	putAll(Map<? extends K,? extends Set<V>> map) Overrides the default behavior of the method by merging the immutable sets for the same key.
Set<V>	remove(K key) Delegates to TransactionalMap.remove(Object) replacing the returned null value with an empty set.
Set<V>	remove(K key, V value) Removes the given value from the entry with the given key.
int	size() Delegates to TransactionalMap.size().
protected void	update(TransactionalMultimap<K,V> changes, boolean onlyReadLogs) Updates local changes and change logs using change logs of the arguments.

Methods inherited from class java.lang.Object

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

Constructor Detail

TransactionalMultimap

public TransactionalMultimap()

Constructs a new empty TransactionalMultimap.

Method Detail

size

public int size()

Delegates to TransactionalMap.size().

Specified by:

size in interface OpaqueMultimap<K,V>

Returns:

the number of key-value mappings in this map

isEmpty

public boolean isEmpty()

Delegates to TransactionalMap.isEmpty().

Specified by:

isEmpty in interface OpaqueMultimap<K,V>

Returns:

true if this map contains no key-value mappings

get

public Set<V> get(K key)

Delegates to TransactionalMap.get(Object) replacing the returned null value with an empty set.

Specified by:

get in interface OpaqueMultimap<K,V>

Parameters:

key - the key whose associated value is to be returned

Returns:

the value to which the specified key is mapped, or null if this map contains no mapping for the key

remove

public Set<V> remove(K key)

Delegates to TransactionalMap.remove(Object) replacing the returned null value with an empty set.

Specified by:

remove in interface OpaqueMultimap<K,V>

Parameters:

key - key whose mapping is to be removed from the map

Returns:

the previous value associated with key, or null if there was no mapping for key.

clear

public void clear()

Description copied from interface: OpaqueMultimap

Removes all of the mappings from this map (optional operation). The map will be empty after this call returns.

Specified by:

clear in interface OpaqueMultimap<K,V>

containsKey

public boolean containsKey(K key)

Description copied from interface: OpaqueMultimap

Returns true if this map contains a mapping for the specified key. More formally, returns true if and only if this map contains a mapping for a key k such that (key==null ? k==null : key.equals(k)). (There can be at most one such mapping.)

Specified by:

containsKey in interface OpaqueMultimap<K,V>

Parameters:

key - key whose presence in this map is to be tested

Returns:

true if this map contains a mapping for the specified key

putAll

public void putAll(Map<? extends K,? extends Set<V>> map)

Overrides the default behavior of the method by merging the immutable sets for the same key.

Specified by:

putAll in interface OpaqueMultimap<K,V>

Parameters:

map - mappings to be stored in this map

keySet

public Set<K> keySet()

Delegates to TransactionalMap.keySet().

Specified by:

keySet in interface OpaqueMultimap<K,V>

Returns:

a set view of the keys contained in this map

put

public Set<V> put(K key,
         V value)

Adds the value to the entry with the given key.

Specified by:

put in interface OpaqueMultimap<K,V>

Parameters:

key - The key that the set is stored under.

value - The value that is added to the entry with the given key.

Returns:

The replaced set or an empty set if there was no entry with the given key.

putAll

public Set<V> putAll(K key,
            Collection<V> values)

Puts all the values in the collection with the given key.

Parameters:

key - The key that the set is stored under.

values - The values that are added to the entry with the given key.

Returns:

The replaced set or an empty set if there was no entry with the given key.

remove

public Set<V> remove(K key,
            V value)

Removes the given value from the entry with the given key. If there are no more values for the key, removes the whole entry from the map.

Parameters:

key - The key to retrieve the set.

value - Value to be removed from the set.

Returns:

The replaced set or an empty set if there was no entry with the given key.

commit

public TransactionalMultimap<K,V> commit(TransactionalMultimap<K,V> globalState)

cleanCopy

protected TransactionalMultimap<K,V> cleanCopy()

Description copied from class: SemiPersistent

Creates a new transactional entity from the current one discarding all the local changes.

Specified by:

cleanCopy in class SemiPersistent<TransactionalMultimap<K,V>>

Returns:

The new entity with no local changes.

dirtyCopy

protected TransactionalMultimap<K,V> dirtyCopy()

Description copied from class: SemiPersistent

Copies references to the source data along with local changes and read/write logs.
Note: It is very important to copy source data by reference, otherwise SemiPersistent#update(Object) will not work.

Specified by:

dirtyCopy in class SemiPersistent<TransactionalMultimap<K,V>>

Returns:

Dirty copy of this collection, with all the local changes and read/write logs preserved.

update

protected void update(TransactionalMultimap<K,V> changes,
          boolean onlyReadLogs)

Description copied from class: SemiPersistent

Updates local changes and change logs using change logs of the arguments. Argument must be constructed from this using SemiPersistent.dirtyCopy().
Note: Any changes done to this collections after branching will be discarded.

Specified by:

update in class SemiPersistent<TransactionalMultimap<K,V>>

Parameters:

changes - The branched collection possibly with updates.

onlyReadLogs - If true only read logs are updated. Useful for read-only transactions.