ReadyPartialFuture (FoundationDB Java Client API)

java.lang.Object
- com.foundationdb.async.ReadyPartialFuture<T>

Type Parameters:
T - the type of value that can be set

All Implemented Interfaces:

Cancellable, PartialFuture<T>, Disposable

Direct Known Subclasses:

ReadyFuture
```
public class ReadyPartialFuture<T>
extends Object
implements PartialFuture<T>
```
A PartialFuture that is always in the "set" state. No call on a ReadyPartialFuture will block, since this is either a value or an error from its time of creation. A ReadyPartialFuture is useful for returning the result of an asynchronous process.

If code needs to return a Future<Void> to indicate completion, ReadyFuture.DONE should be used.

Constructor Summary

Constructors
Constructor and Description
`ReadyPartialFuture(Error error)` Create a new `ReadyFuture` set to an error.
`ReadyPartialFuture(Error error, Executor executor)` Create a new `ReadyFuture` set to an error.
`ReadyPartialFuture(Exception error)` Create a new `ReadyPartialFuture` set to an error.
`ReadyPartialFuture(Exception error, Executor executor)` Create a new `ReadyFuture` set to an error.
`ReadyPartialFuture(T value)` Create a new `ReadyFuture` set to a value.
`ReadyPartialFuture(T value, Executor executor)` Create a new `ReadyPartialFuture` set to a value.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`blockInterruptibly()` Blocks until this `Future` is set to either a value or an error.
`void`	`blockUntilReady()` Always returns immediately.
`void`	`cancel()` Does nothing, as a `ReadyPartialFuture` cannot be cancelled.
`void`	`dispose()` Equivalent to calling `PartialFuture.cancel()`.
`<V> PartialFuture<V>`	`flatMap(PartialFunction<? super T,? extends PartialFuture<V>> m)` Applies the successful result of this operation as the input into another asynchronous operation and returns a handle to that result.
`T`	`get()` Blocks until a value is set on this `PartialFuture` and returns it.
`Throwable`	`getError()` Gets the error from a `Future` if it has been set to this state.
`T`	`getInterruptibly()` Blocks until a value is set on this `PartialFuture` and returns it.
`boolean`	`isDone()` A `ReadyFuture` is always done.
`boolean`	`isError()` Tests if this `Future` is set to an error
`<V> PartialFuture<V>`	`map(PartialFunction<? super T,V> m)` Apply a function to the successful result of this operation.
`void`	`onReady(Runnable r)` Registers a `Runnable` to run as the callback for this `Future` on a default thread.
`boolean`	`onReadyAlready(Runnable r)` Checks if this `Future` is ready and, if not, atomically registers a `Runnable` to run as the callback for this future on a default thread.
`Future<T>`	`rescue(Function<? super Exception,Future<T>> m)` Convert an error output of this operation into another asynchronous process.
`PartialFuture<T>`	`rescue(PartialFunction<? super Exception,? extends PartialFuture<T>> m)` Map any error result of this `Future` to another asynchronous process.

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

- Constructor Detail
  - ReadyPartialFuture
```
public ReadyPartialFuture(T value)
```
    Create a new ReadyFuture set to a value.
    
    Parameters:
    value - the final value of this Future
  - ReadyPartialFuture
```
public ReadyPartialFuture(Error error)
```
    Create a new ReadyFuture set to an error. If error is null the Future will be set to a null value and NOT an error.
    
    Parameters:
    error - the final error of this Future
  - ReadyPartialFuture
```
public ReadyPartialFuture(Exception error)
```
    Create a new ReadyPartialFuture set to an error. If error is null the Future will be set to a null value and NOT an error.
    
    Parameters:
    error - the final error of this Future
  - ReadyPartialFuture
```
public ReadyPartialFuture(T value,
                  Executor executor)
```
    Create a new ReadyPartialFuture set to a value.
    
    Parameters:
    value - the final value of this Future
    executor - the executor with which to execute callbacks
  - ReadyPartialFuture
```
public ReadyPartialFuture(Error error,
                  Executor executor)
```
    Create a new ReadyFuture set to an error. If error is null the Future will be set to a null value and NOT an error.
    
    Parameters:
    error - the final error of this Future
    executor - the executor with which to execute callbacks
  - ReadyPartialFuture
```
public ReadyPartialFuture(Exception error,
                  Executor executor)
```
    Create a new ReadyFuture set to an error. If error is null the Future will be set to a null value and NOT an error.
    
    Parameters:
    error - the final error of this Future
    executor - the executor with which to execute callbacks
- Method Detail
  - cancel
```
public void cancel()
```
    Does nothing, as a ReadyPartialFuture cannot be cancelled.
    
    Specified by:
    
    cancel in interface Cancellable
    
    Specified by:
    
    cancel in interface PartialFuture<T>
  - onReady
```
public void onReady(Runnable r)
```
    Description copied from interface: PartialFuture
    
    Registers a Runnable to run as the callback for this Future on a default thread. It will be called after the future becomes ready, including if the future is set to a value, set to an error, or cancelled.
    
    Consider using PartialFuture.map(PartialFunction) and PartialFuture.flatMap(PartialFunction) instead, as they automatically provide error propagation and cancellation.
    
    Specified by:
    
    onReady in interface PartialFuture<T>
    
    Parameters:
    r - the code to run when the future is set either to value or error
  - onReadyAlready
```
public boolean onReadyAlready(Runnable r)
```
    Description copied from interface: PartialFuture
    
    Checks if this Future is ready and, if not, atomically registers a Runnable to run as the callback for this future on a default thread. The callback will not be called if the future is ready. Callers can rely on the guarantee that if this function returns false their callback will be executed on completion (including if the future is set to a value, set to an error, or cancelled), and if true they can then call PartialFuture.get() without blocking.
    
    Specified by:
    
    onReadyAlready in interface PartialFuture<T>
    
    Parameters:
    r - the code to run when the future is set if it is not currently ready
    
    Returns:
    true if the future is ready, false otherwise
  - flatMap
```
public <V> PartialFuture<V> flatMap(PartialFunction<? super T,? extends PartialFuture<V>> m)
```
    Description copied from interface: PartialFuture
    
    Applies the successful result of this operation as the input into another asynchronous operation and returns a handle to that result. That is, when the operation represented by this Future is complete and a result is returned, the Mapper m is invoked to begin a new asynchronous process using the result. Errors in the execution of either operation are sent to the resulting Future.
    
    If the returned Future is cancelled the input input Future will also be cancelled.
    
    Specified by:
    
    flatMap in interface PartialFuture<T>
    
    Parameters:
    m - the map to the asynchronous process to be run
    
    Returns:
    a new Future that passes errors and converts output of this Future to the output of another asynchronous process.
  - map
```
public <V> PartialFuture<V> map(PartialFunction<? super T,V> m)
```
    Description copied from interface: PartialFuture
    
    Apply a function to the successful result of this operation. Errors in the execution of this operation are sent to the resulting Future.
    
    If the returned Future is cancelled the input input Future will also be cancelled.
    
    Specified by:
    
    map in interface PartialFuture<T>
    
    Parameters:
    m - the map to the conversion to be run
    
    Returns:
    a new Future that passes errors and converts output of this Future.
  - rescue
```
public Future<T> rescue(Function<? super Exception,Future<T>> m)
```
    Description copied from interface: PartialFuture
    
    Convert an error output of this operation into another asynchronous process.
    
    Specified by:
    
    rescue in interface PartialFuture<T>
    
    Parameters:
    m - the process to run on completion into error state.
    
    Returns:
    the non-checked Future output with modified error behavior
  - rescue
```
public PartialFuture<T> rescue(PartialFunction<? super Exception,? extends PartialFuture<T>> m)
```
    Description copied from interface: PartialFuture
    
    Map any error result of this Future to another asynchronous process. This can be used when an error is expected or can be logically dealt with in some way. If the rescue process cannot handle the error, or if the rescue process itself throws an error, that error will be set on this Future. If the result of this call is used in place of this Future, the user of the output Future will see successes of this process, successes of the rescue process, or errors from the rescue process.
    
    Specified by:
    
    rescue in interface PartialFuture<T>
    
    Parameters:
    m - the process to run that maps an error into another asynchronous operation
    
    Returns:
    a newly created Future with modified error behavior
  - blockUntilReady
```
public void blockUntilReady()
```
    Always returns immediately.
    
    Specified by:
    
    blockUntilReady in interface PartialFuture<T>
  - blockInterruptibly
```
public void blockInterruptibly()
```
    Description copied from interface: PartialFuture
    
    Blocks until this Future is set to either a value or an error. When this function returns without an error, PartialFuture.isDone() will return true.
    Code should never block for a future to become ready in code invoked as a callback. Blocking in callback code will generally block client networking and cause a deadlock.
    
    Specified by:
    
    blockInterruptibly in interface PartialFuture<T>
  - get
```
public T get()
      throws Exception
```
    Description copied from interface: PartialFuture
    
    Blocks until a value is set on this PartialFuture and returns it. If this PartialFuture is set to an Exception or Error this call will throw that error.
    
    Specified by:
    
    get in interface PartialFuture<T>
    
    Returns:
    the output value of the asynchronous process
    
    Throws:
    
    Exception - if the process was not successfully executed.
    
    InterruptedException - if the blocked thread is interrupted
  - getInterruptibly
```
public T getInterruptibly()
                   throws Exception
```
    Description copied from interface: PartialFuture
    
    Blocks until a value is set on this PartialFuture and returns it. If this PartialFuture is set to an Exception or Error this call will throw that error.
    
    Specified by:
    
    getInterruptibly in interface PartialFuture<T>
    
    Returns:
    the output value of the asynchronous process
    
    Throws:
    
    Exception - if the process was not successfully executed.
    
    InterruptedException - if the blocked thread is interrupted
  - isDone
```
public boolean isDone()
```
    A ReadyFuture is always done.
    
    Specified by:
    
    isDone in interface PartialFuture<T>
    
    Returns:
    always returns true.
  - isError
```
public boolean isError()
```
    Description copied from interface: PartialFuture
    
    Tests if this Future is set to an error
    
    Specified by:
    
    isError in interface PartialFuture<T>
    
    Returns:
    true if in error state, false otherwise
  - getError
```
public Throwable getError()
```
    Description copied from interface: PartialFuture
    
    Gets the error from a Future if it has been set to this state. If this Future is not yet set, or has not been set to an error, throws an exception. Although this method returns a Throwable, the set of possible types is more limited. A PartialFuture is limited to be set in an error state to an Exception (or a subclass thereof) or an unchecked Error.
    
    Specified by:
    
    getError in interface PartialFuture<T>
    
    Returns:
    the error output of the Future
  - dispose
```
public void dispose()
```
    Description copied from interface: PartialFuture
    
    Equivalent to calling PartialFuture.cancel().
    
    Specified by:
    
    dispose in interface PartialFuture<T>
    
    Specified by:
    
    dispose in interface Disposable

Class ReadyPartialFuture<T>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

ReadyPartialFuture

ReadyPartialFuture

ReadyPartialFuture

ReadyPartialFuture

ReadyPartialFuture

ReadyPartialFuture

Method Detail

cancel

onReady

onReadyAlready

flatMap

map

rescue

rescue

blockUntilReady

blockInterruptibly

get

getInterruptibly

isDone

isError

getError

dispose