java.lang.Object
- org.springframework.web.context.request.async.DeferredResult<T>

类型参数:
T - the result type
```
public class DeferredResult<T>
extends Object
```
DeferredResult provides an alternative to using a Callable for asynchronous request processing. While a Callable is executed concurrently on behalf of the application, with a DeferredResult the application can produce the result from a thread of its choice.
Subclasses can extend this class to easily associate additional data or behavior with the DeferredResult. For example, one might want to associate the user used to create the DeferredResult by extending the class and adding an additional property for the user. In this way, the user could easily be accessed later without the need to use a data structure to do the mapping.
An example of associating additional behavior to this class might be realized by extending the class to implement an additional interface. For example, one might want to implement Comparable so that when the DeferredResult is added to a PriorityQueue it is handled in the correct order.
从以下版本开始:
3.2
作者:
Rossen Stoyanchev, Juergen Hoeller, Rob Winch

嵌套类概要
嵌套类
修饰符和类型类说明
static interface DeferredResult.DeferredResultHandler
Handles a DeferredResult value when set.

构造器概要

构造器
构造器	说明
`DeferredResult()`	Create a DeferredResult.
`DeferredResult(Long timeoutValue)`	Create a DeferredResult with a custom timeout value.
`DeferredResult(Long timeoutValue, Object timeoutResult)`	Create a DeferredResult with a timeout value and a default result to use in case of timeout.
`DeferredResult(Long timeoutValue, Supplier<?> timeoutResult)`	Variant of `DeferredResult(Long, Object)` that accepts a dynamic fallback value based on a `Supplier`.

方法概要

所有方法实例方法具体方法
修饰符和类型	方法	说明
`Object`	`getResult()`	Return the result, or `null` if the result wasn't set.
`boolean`	`hasResult()`	Return `true` if the DeferredResult has been set.
`boolean`	`isSetOrExpired()`	Return `true` if this DeferredResult is no longer usable either because it was previously set or because the underlying request expired.
`void`	`onCompletion(Runnable callback)`	Register code to invoke when the async request completes.
`void`	`onError(Consumer<Throwable> callback)`	Register code to invoke when an error occurred during the async request.
`void`	`onTimeout(Runnable callback)`	Register code to invoke when the async request times out.
`boolean`	`setErrorResult(Object result)`	Set an error value for the `DeferredResult` and handle it.
`boolean`	`setResult(T result)`	Set the value for the DeferredResult and handle it.
`void`	`setResultHandler(DeferredResult.DeferredResultHandler resultHandler)`	Provide a handler to use to handle the result value.

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 构造器详细资料
  - DeferredResult
```
public DeferredResult()
```
    Create a DeferredResult.
  - DeferredResult
```
public DeferredResult(Long timeoutValue)
```
    Create a DeferredResult with a custom timeout value.
    By default not set in which case the default configured in the MVC Java Config or the MVC namespace is used, or if that's not set, then the timeout depends on the default of the underlying server.
    参数:
    timeoutValue - timeout value in milliseconds
  - DeferredResult
```
public DeferredResult(@Nullable
                      Long timeoutValue,
                      Object timeoutResult)
```
    Create a DeferredResult with a timeout value and a default result to use in case of timeout.
    参数:
    timeoutValue - timeout value in milliseconds (ignored if null)
    timeoutResult - the result to use
  - DeferredResult
```
public DeferredResult(@Nullable
                      Long timeoutValue,
                      Supplier<?> timeoutResult)
```
    Variant of DeferredResult(Long, Object) that accepts a dynamic fallback value based on a Supplier.
    参数:
    timeoutValue - timeout value in milliseconds (ignored if null)
    timeoutResult - the result supplier to use
    从以下版本开始:
    5.1.1
- 方法详细资料
  - isSetOrExpired
```
public final boolean isSetOrExpired()
```
    Return true if this DeferredResult is no longer usable either because it was previously set or because the underlying request expired.
    The result may have been set with a call to setResult(Object), or setErrorResult(Object), or as a result of a timeout, if a timeout result was provided to the constructor. The request may also expire due to a timeout or network error.
  - hasResult
```
public boolean hasResult()
```
    Return true if the DeferredResult has been set.
    从以下版本开始:
    4.0
  - getResult
```
@Nullable
public Object getResult()
```
    Return the result, or null if the result wasn't set. Since the result can also be null, it is recommended to use hasResult() first to check if there is a result prior to calling this method.
    从以下版本开始:
    4.0
  - onTimeout
```
public void onTimeout(Runnable callback)
```
    Register code to invoke when the async request times out.
    This method is called from a container thread when an async request times out before the DeferredResult has been populated. It may invoke setResult or setErrorResult to resume processing.
  - onError
```
public void onError(Consumer<Throwable> callback)
```
    Register code to invoke when an error occurred during the async request.
    This method is called from a container thread when an error occurs while processing an async request before the DeferredResult has been populated. It may invoke setResult or setErrorResult to resume processing.
    从以下版本开始:
    5.0
  - onCompletion
```
public void onCompletion(Runnable callback)
```
    Register code to invoke when the async request completes.
    This method is called from a container thread when an async request completed for any reason including timeout and network error. This is useful for detecting that a DeferredResult instance is no longer usable.
  - setResultHandler
```
public final void setResultHandler(DeferredResult.DeferredResultHandler resultHandler)
```
    Provide a handler to use to handle the result value.
    参数:
    resultHandler - the handler
    另请参阅:
    DeferredResultProcessingInterceptor
  - setResult
```
public boolean setResult(T result)
```
    Set the value for the DeferredResult and handle it.
    参数:
    result - the value to set
    返回:
    true if the result was set and passed on for handling; false if the result was already set or the async request expired
    另请参阅:
    isSetOrExpired()
  - setErrorResult
```
public boolean setErrorResult(Object result)
```
    Set an error value for the DeferredResult and handle it. The value may be an Exception or Throwable in which case it will be processed as if a handler raised the exception.
    参数:
    result - the error result value
    返回:
    true if the result was set to the error value and passed on for handling; false if the result was already set or the async request expired
    另请参阅:
    isSetOrExpired()

类 DeferredResult<T>

嵌套类概要

构造器概要

方法概要

从类继承的方法 java.lang.Object

构造器详细资料

DeferredResult

DeferredResult

DeferredResult

DeferredResult

方法详细资料

isSetOrExpired

hasResult

getResult

onTimeout

onError

onCompletion

setResultHandler

setResult

setErrorResult