org.mapdb

Class Atomic.Var<E>

java.lang.Object

org.mapdb.Atomic.Var<E>

Enclosing class:

Atomic

public static final class Atomic.Var<E>
extends java.lang.Object

Atomically updated variable which may contain any type of record. Atomic.Var does not allow nulls. Initial value of newly created vars is empty string ""

Field Summary

Fields

Modifier and Type	Field and Description
protected Engine	engine
protected long	recid
protected Serializer<E>	serializer

Constructor Summary

Constructors

Modifier	Constructor and Description
	Var(Engine engine, long recid, Serializer<E> serializer)
protected	Var(Engine engine, SerializerBase serializerBase, java.io.DataInput is, SerializerBase.FastArrayList<java.lang.Object> objectStack) used for deserialization

Method Summary

Modifier and Type	Method and Description
boolean	compareAndSet(E expect, E update) Atomically sets the value to the given updated value if the current value equals the expected value.
E	get() Returns the current value.
E	getAndSet(E newValue) Atomically sets to the given value and returns the previous value.
long	getRecid()
void	set(E newValue) Unconditionally sets to the given value.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

engine

protected final Engine engine

recid

protected final long recid

serializer

protected final Serializer<E> serializer

Constructor Detail

Var

public Var(Engine engine,
           long recid,
           Serializer<E> serializer)

Var

protected Var(Engine engine,
              SerializerBase serializerBase,
              java.io.DataInput is,
              SerializerBase.FastArrayList<java.lang.Object> objectStack)
       throws java.io.IOException

used for deserialization

Throws:

java.io.IOException

Method Detail

getRecid

public long getRecid()

Returns:

recid under which value is saved

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

get

public final E get()

Returns the current value.

Returns:

the current value

compareAndSet

public final boolean compareAndSet(E expect,
                                   E update)

Atomically sets the value to the given updated value if the current value equals the expected value.

Parameters:

expect - the expected value

update - the new value

Returns:

true if successful. False return indicates that the actual value was not equal to the expected value.

set

public final void set(E newValue)

Unconditionally sets to the given value.

Parameters:

newValue - the new value

getAndSet

public final E getAndSet(E newValue)

Atomically sets to the given value and returns the previous value.

Parameters:

newValue - the new value

Returns:

the previous value