Java compact1, compact2, compact3 java.util.concurrent.atomic Class AtomicLongFieldUpdater<T>（JDK8）

Constructor Detail

• AtomicLongFieldUpdater

  protected AtomicLongFieldUpdater()

  Protected do-nothing constructor for use by subclasses.

Method Detail

• newUpdater

  public static <U> AtomicLongFieldUpdater<U> newUpdater(Class<U> tclass,
                                                         String fieldName)

  Creates and returns an updater for objects with the given field. The Class argument is needed to check that reflective types and generic types match.

  Type Parameters:

  U - the type of instances of tclass

  Parameters:

  tclass - the class of the objects holding the field

  fieldName - the name of the field to be updated

  Returns:

  the updater

  Throws:

  IllegalArgumentException - if the field is not a volatile long type

  RuntimeException - with a nested reflection-based exception if the class does not hold field or is the wrong type, or the field is inaccessible to the caller according to Java language access control

• compareAndSet

  public abstract boolean compareAndSet(T obj,
                                        long expect,
                                        long update)

  Atomically sets the field of the given object managed by this updater to the given updated value if the current value == the expected value. This method is guaranteed to be atomic with respect to other calls to compareAndSet and set, but not necessarily with respect to other changes in the field.

  Parameters:

  obj - An object whose field to conditionally set

  expect - the expected value

  update - the new value

  Returns:

  true if successful

  Throws:

  ClassCastException - if obj is not an instance of the class possessing the field established in the constructor

• weakCompareAndSet

  public abstract boolean weakCompareAndSet(T obj,
                                            long expect,
                                            long update)

  Atomically sets the field of the given object managed by this updater to the given updated value if the current value == the expected value. This method is guaranteed to be atomic with respect to other calls to compareAndSet and set, but not necessarily with respect to other changes in the field.

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

  Parameters:

  obj - An object whose field to conditionally set

  expect - the expected value

  update - the new value

  Returns:

  true if successful

  Throws:

  ClassCastException - if obj is not an instance of the class possessing the field established in the constructor

• set

  public abstract void set(T obj,
                           long newValue)

  Sets the field of the given object managed by this updater to the given updated value. This operation is guaranteed to act as a volatile store with respect to subsequent invocations of compareAndSet.

  Parameters:

  obj - An object whose field to set

  newValue - the new value

• lazySet

  public abstract void lazySet(T obj,
                               long newValue)

  Eventually sets the field of the given object managed by this updater to the given updated value.

  Parameters:

  obj - An object whose field to set

  newValue - the new value

  Since:

  1.6

• get

  public abstract long get(T obj)

  Gets the current value held in the field of the given object managed by this updater.

  Parameters:

  obj - An object whose field to get

  Returns:

  the current value

• getAndSet

  public long getAndSet(T obj,
                        long newValue)

  Atomically sets the field of the given object managed by this updater to the given value and returns the old value.

  Parameters:

  obj - An object whose field to get and set

  newValue - the new value

  Returns:

  the previous value

• getAndIncrement

  public long getAndIncrement(T obj)

  Atomically increments by one the current value of the field of the given object managed by this updater.

  Parameters:

  obj - An object whose field to get and set

  Returns:

  the previous value

• getAndDecrement

  public long getAndDecrement(T obj)

  Atomically decrements by one the current value of the field of the given object managed by this updater.

  Parameters:

  obj - An object whose field to get and set

  Returns:

  the previous value

• getAndAdd

  public long getAndAdd(T obj,
                        long delta)

  Atomically adds the given value to the current value of the field of the given object managed by this updater.

  Parameters:

  obj - An object whose field to get and set

  delta - the value to add

  Returns:

  the previous value

• incrementAndGet

  public long incrementAndGet(T obj)

  Atomically increments by one the current value of the field of the given object managed by this updater.

  Parameters:

  obj - An object whose field to get and set

  Returns:

  the updated value

• decrementAndGet

  public long decrementAndGet(T obj)

  Atomically decrements by one the current value of the field of the given object managed by this updater.

  Parameters:

  obj - An object whose field to get and set

  Returns:

  the updated value

• addAndGet

  public long addAndGet(T obj,
                        long delta)

  Atomically adds the given value to the current value of the field of the given object managed by this updater.

  Parameters:

  obj - An object whose field to get and set

  delta - the value to add

  Returns:

  the updated value

• getAndUpdate

  public final long getAndUpdate(T obj,
                                 LongUnaryOperator updateFunction)

  Atomically updates the field of the given object managed by this updater with the results of applying the given function, returning the previous value. The function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads.

  Parameters:

  obj - An object whose field to get and set

  updateFunction - a side-effect-free function

  Returns:

  the previous value

  Since:

  1.8

• updateAndGet

  public final long updateAndGet(T obj,
                                 LongUnaryOperator updateFunction)

  Atomically updates the field of the given object managed by this updater with the results of applying the given function, returning the updated value. The function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads.

  Parameters:

  obj - An object whose field to get and set

  updateFunction - a side-effect-free function

  Returns:

  the updated value

  Since:

  1.8

• getAndAccumulate

  public final long getAndAccumulate(T obj,
                                     long x,
                                     LongBinaryOperator accumulatorFunction)

  Atomically updates the field of the given object managed by this updater with the results of applying the given function to the current and given values, returning the previous value. The function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads. The function is applied with the current value as its first argument, and the given update as the second argument.

  Parameters:

  obj - An object whose field to get and set

  x - the update value

  accumulatorFunction - a side-effect-free function of two arguments

  Returns:

  the previous value

  Since:

  1.8

• accumulateAndGet

  public final long accumulateAndGet(T obj,
                                     long x,
                                     LongBinaryOperator accumulatorFunction)

  Atomically updates the field of the given object managed by this updater with the results of applying the given function to the current and given values, returning the updated value. The function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads. The function is applied with the current value as its first argument, and the given update as the second argument.

  Parameters:

  obj - An object whose field to get and set

  x - the update value

  accumulatorFunction - a side-effect-free function of two arguments

  Returns:

  the updated value

  Since:

  1.8