org.apache.curator.framework.recipes.atomic

Interface DistributedAtomicNumber<T>

All Known Implementing Classes:

DistributedAtomicInteger, DistributedAtomicLong

public interface DistributedAtomicNumber<T>

Method Summary

Modifier and Type	Method and Description
AtomicValue<T>	add(T delta) Add delta to the current value and return the new value information.
AtomicValue<T>	compareAndSet(T expectedValue, T newValue) Atomically sets the value to the given updated value if the current value == the expected value.
AtomicValue<T>	decrement() Subtract 1 from the current value and return the new value information.
void	forceSet(T newValue) Forcibly sets the value of the counter without any guarantees of atomicity.
AtomicValue<T>	get() Returns the current value of the counter.
AtomicValue<T>	increment() Add 1 to the current value and return the new value information.
boolean	initialize(T value) Atomic values are initially set to the equivalent of NULL in a database.
AtomicValue<T>	subtract(T delta) Subtract delta from the current value and return the new value information.
AtomicValue<T>	trySet(T newValue) Attempt to atomically set the value to the given value.

Method Detail

get

AtomicValue<T> get()
            throws Exception

Returns the current value of the counter. NOTE: if the value has never been set, 0 is returned.

Returns:

value info

Throws:

Exception - ZooKeeper errors

compareAndSet

AtomicValue<T> compareAndSet(T expectedValue,
                             T newValue)
                      throws Exception

Atomically sets the value to the given updated value if the current value == the expected value. Remember to always check AtomicValue.succeeded().

Parameters:

expectedValue - the expected value

newValue - the new value for the counter

Returns:

value info

Throws:

Exception - ZooKeeper errors

trySet

AtomicValue<T> trySet(T newValue)
               throws Exception

Attempt to atomically set the value to the given value. Remember to always check AtomicValue.succeeded().

Parameters:

newValue - the value to set

Returns:

value info

Throws:

Exception - ZooKeeper errors

initialize

boolean initialize(T value)
            throws Exception

Atomic values are initially set to the equivalent of NULL in a database. Use this method to initialize the value. The value will be set if and only iff the node does not exist.

Parameters:

value - the initial value to set

Returns:

true if the value was set, false if the node already existed

Throws:

Exception - ZooKeeper errors

forceSet

void forceSet(T newValue)
       throws Exception

Forcibly sets the value of the counter without any guarantees of atomicity.

Parameters:

newValue - the new value

Throws:

Exception - ZooKeeper errors

increment

AtomicValue<T> increment()
                  throws Exception

Add 1 to the current value and return the new value information. Remember to always check AtomicValue.succeeded().

Returns:

value info

Throws:

Exception - ZooKeeper errors

decrement

AtomicValue<T> decrement()
                  throws Exception

Subtract 1 from the current value and return the new value information. Remember to always check AtomicValue.succeeded().

Returns:

value info

Throws:

Exception - ZooKeeper errors

add

AtomicValue<T> add(T delta)
            throws Exception

Add delta to the current value and return the new value information. Remember to always check AtomicValue.succeeded().

Parameters:

delta - amount to add

Returns:

value info

Throws:

Exception - ZooKeeper errors

subtract

AtomicValue<T> subtract(T delta)
                 throws Exception

Subtract delta from the current value and return the new value information. Remember to always check AtomicValue.succeeded().

Parameters:

delta - amount to subtract

Returns:

value info

Throws:

Exception - ZooKeeper errors