AtomicBoolean

AI-generated Key Takeaways

• AtomicBoolean provides a way to update a boolean value atomically, ensuring thread safety during concurrent operations.

• It offers methods like compareAndSet, get, and set for manipulating the boolean value in a thread-safe manner.

• AtomicBoolean is commonly used for atomically updated flags but cannot be used as a replacement for a regular Boolean object.

• Constructors allow initialization with a specific boolean value or a default value of false.

• weakCompareAndSet is available but should be used cautiously due to its potential for spurious failures and lack of ordering guarantees.

public class AtomicBoolean extends Object
implements Serializable

A boolean value that may be updated atomically. See the java.util.concurrent.atomic package specification for description of the properties of atomic variables. An AtomicBoolean is used in applications such as atomically updated flags, and cannot be used as a replacement for a Boolean.

Public Constructor Summary

	AtomicBoolean(boolean initialValue) Creates a new AtomicBoolean with the given initial value.
	AtomicBoolean() Creates a new AtomicBoolean with initial value false.

Public Method Summary

final boolean	compareAndSet(boolean expect, boolean update) Atomically sets the value to the given updated value if the current value == the expected value.
final boolean	get() Returns the current value.
final boolean	getAndSet(boolean newValue) Atomically sets to the given value and returns the previous value.
final void	lazySet(boolean newValue) Eventually sets to the given value.
final void	set(boolean newValue) Unconditionally sets to the given value.
String	toString() Returns the String representation of the current value.
boolean	weakCompareAndSet(boolean expect, boolean update) Atomically sets the value to the given updated value if the current value == the expected value.

Inherited Method Summary

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

Public Constructors

public AtomicBoolean (boolean initialValue)

Creates a new AtomicBoolean with the given initial value.

Parameters

initialValue	the initial value

public AtomicBoolean ()

Creates a new AtomicBoolean with initial value false.

Public Methods

public final boolean compareAndSet (boolean expect, boolean update)

Atomically sets the value to the given updated value if the current value == 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.

public final boolean get ()

Returns the current value.

Returns

• the current value

public final boolean getAndSet (boolean newValue)

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

Parameters

newValue	the new value

Returns

• the previous value

public final void lazySet (boolean newValue)

Eventually sets to the given value.

Parameters

newValue	the new value

public final void set (boolean newValue)

Unconditionally sets to the given value.

Parameters

newValue	the new value

public String toString ()

Returns the String representation of the current value.

Returns

• the String representation of the current value

public boolean weakCompareAndSet (boolean expect, boolean update)

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

May fail spuriously and does not provide ordering guarantees, so is only rarely an appropriate alternative to compareAndSet.

Parameters

expect	the expected value
update	the new value

Returns

• true if successful