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## java.util.concurrent.atomic
Class AtomicIntegerFieldUpdater<T>

    java.lang.Object
      java.util.concurrent.atomic.AtomicIntegerFieldUpdater<T>

Type Parameters:
  `T` - The type of the object holding the updatable field

    public abstract class AtomicIntegerFieldUpdater<T>

extends Object

A reflection-based utility that enables atomic updates to designated `volatile int` fields of designated classes. This class is designed for use in atomic data structures in which several fields of the same node are independently subject to atomic updates.

Note that the guarantees of the `compareAndSet` method in this class are weaker than in other atomic classes. Because this class cannot ensure that all uses of the field are appropriate for purposes of atomic access, it can guarantee atomicity and volatile semantics only with respect to other invocations of `compareAndSet` and `set`.

Since:
  1.5

Constructor Summary
`protected` | `AtomicIntegerFieldUpdater()` Protected do-nothing constructor for use by subclasses.

Method Summary
`int` | `addAndGet(T obj, int delta)` Atomically add the given value to current value.
`abstract boolean` | `compareAndSet(T obj, int expect, int update)` Atomically set the value of the field of the given object managed by this Updater to the given updated value if the current value `==` the expected value.
`int` | `decrementAndGet(T obj)` Atomically decrement by one the current value.
`abstract int` | `get(T obj)` Get the current value held in the field by the given object.
`int` | `getAndAdd(T obj, int delta)` Atomically add the given value to current value.
`int` | `getAndDecrement(T obj)` Atomically decrement by one the current value.
`int` | `getAndIncrement(T obj)` Atomically increment by one the current value.
`int` | `getAndSet(T obj, int newValue)` Set to the given value and return the old value.
`int` | `incrementAndGet(T obj)` Atomically increment by one the current value.
`static
`<U> AtomicIntegerFieldUpdater<U>`
` | `newUpdater(Class<U> tclass, String fieldName)` Creates an updater for objects with the given field.
`abstract void` | `set(T obj, int newValue)` Set the field of the given object managed by this updater.
`abstract boolean` | `weakCompareAndSet(T obj, int expect, int update)` Atomically set the value of the field of the given object managed by this Updater to the given updated value if the current value `==` the expected value.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### AtomicIntegerFieldUpdater

    protected AtomicIntegerFieldUpdater()

  Protected do-nothing constructor for use by subclasses.

Method Detail

### newUpdater

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

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

  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 integer type.
    `RuntimeException` - with a nested reflection-based exception if the class does not hold field or is the wrong type.

### compareAndSet

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

  Atomically set the value of 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,
                                              int expect,
                                              int update)

  Atomically set the value of 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, and may fail spuriously.

  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,
                             int newValue)

  Set the field of the given object managed by this updater. 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

### get

    public abstract int get(T obj)

  Get the current value held in the field by the given object.

  Parameters:
    `obj` - An object whose field to get
  Returns:
    the current value

### getAndSet

    public int getAndSet(T obj,
                         int newValue)

  Set to the given value and return the old value.

  Parameters:
    `obj` - An object whose field to get and set
    `newValue` - the new value
  Returns:
    the previous value

### getAndIncrement

    public int getAndIncrement(T obj)

  Atomically increment by one the current value.

  Parameters:
    `obj` - An object whose field to get and set
  Returns:
    the previous value;

### getAndDecrement

    public int getAndDecrement(T obj)

  Atomically decrement by one the current value.

  Parameters:
    `obj` - An object whose field to get and set
  Returns:
    the previous value;

### getAndAdd

    public int getAndAdd(T obj,
                         int delta)

  Atomically add the given value to current value.

  Parameters:
    `obj` - An object whose field to get and set
    `delta` - the value to add
  Returns:
    the previous value;

### incrementAndGet

    public int incrementAndGet(T obj)

  Atomically increment by one the current value.

  Parameters:
    `obj` - An object whose field to get and set
  Returns:
    the updated value;

### decrementAndGet

    public int decrementAndGet(T obj)

  Atomically decrement by one the current value.

  Parameters:
    `obj` - An object whose field to get and set
  Returns:
    the updated value;

### addAndGet

    public int addAndGet(T obj,
                         int delta)

  Atomically add the given value to current value.

  Parameters:
    `obj` - An object whose field to get and set
    `delta` - the value to add
  Returns:
    the updated value;

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