Class ServletScopes
- java.lang.Object
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- com.google.inject.servlet.ServletScopes
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public final class ServletScopes extends Object
Servlet scopes.
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Method Summary
All Methods Static Methods Concrete Methods Deprecated Methods Modifier and Type Method Description static <T> Callable<T>
continueRequest(Callable<T> callable, Map<Key<?>,Object> seedMap)
Deprecated.You probably want to usetransferRequest
insteadstatic boolean
isRequestScoped(Binding<?> binding)
Returns true ifbinding
is request-scoped.static <T> Callable<T>
scopeRequest(Callable<T> callable, Map<Key<?>,Object> seedMap)
Scopes the given callable inside a request scope.static RequestScoper
scopeRequest(Map<Key<?>,Object> seedMap)
Returns an object that will apply request scope to a block of code.static RequestScoper
transferRequest()
Returns an object that "transfers" the request to another thread.static <T> Callable<T>
transferRequest(Callable<T> callable)
Wraps the given callable in a contextual callable that "transfers" the request to another thread.
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Method Detail
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continueRequest
@Deprecated public static <T> Callable<T> continueRequest(Callable<T> callable, Map<Key<?>,Object> seedMap)
Deprecated.You probably want to usetransferRequest
insteadWraps the given callable in a contextual callable that "continues" the HTTP request in another thread. This acts as a way of transporting request context data from the request processing thread to to worker threads.There are some limitations:
- Derived objects (i.e. anything marked @RequestScoped will not be transported.
- State changes to the HttpServletRequest after this method is called will not be seen in the continued thread.
- Only the HttpServletRequest, ServletContext and request parameter map are available in the continued thread. The response and session are not available.
The returned callable will throw a
ScopingException
when called if the HTTP request scope is still active on the current thread.- Parameters:
callable
- code to be executed in another thread, which depends on the request scope.seedMap
- the initial set of scoped instances for Guice to seed the request scope with. To seed a key with null, usenull
as the value.- Returns:
- a callable that will invoke the given callable, making the request context available to it.
- Throws:
OutOfScopeException
- if this method is called from a non-request thread, or if the request has completed.- Since:
- 3.0
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transferRequest
public static <T> Callable<T> transferRequest(Callable<T> callable)
Wraps the given callable in a contextual callable that "transfers" the request to another thread. This acts as a way of transporting request context data from the current thread to a future thread.As opposed to
continueRequest(java.util.concurrent.Callable<T>, java.util.Map<com.google.inject.Key<?>, java.lang.Object>)
, this method propagates all existing scoped objects. The primary use case is in server implementations where you can detach the request processing thread while waiting for data, and reattach to a different thread to finish processing at a later time.Because request-scoped objects are not typically thread-safe, the callable returned by this method must not be run on a different thread until the current request scope has terminated. The returned callable will block until the current thread has released the request scope.
- Parameters:
callable
- code to be executed in another thread, which depends on the request scope.- Returns:
- a callable that will invoke the given callable, making the request context available to it.
- Throws:
OutOfScopeException
- if this method is called from a non-request thread, or if the request has completed.- Since:
- 4.0
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transferRequest
public static RequestScoper transferRequest()
Returns an object that "transfers" the request to another thread. This acts as a way of transporting request context data from the current thread to a future thread. The transferred scope is the one active for the thread that calls this method. A later call toopen()
activates the transferred the scope, including propagating any objects scoped at that time.As opposed to
continueRequest(java.util.concurrent.Callable<T>, java.util.Map<com.google.inject.Key<?>, java.lang.Object>)
, this method propagates all existing scoped objects. The primary use case is in server implementations where you can detach the request processing thread while waiting for data, and reattach to a different thread to finish processing at a later time.Because request-scoped objects are not typically thread-safe, it is important to avoid applying the same request scope concurrently. The returned Scoper will block on open until the current thread has released the request scope.
- Returns:
- an object that when opened will initiate the request scope
- Throws:
OutOfScopeException
- if this method is called from a non-request thread, or if the request has completed.- Since:
- 4.1
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isRequestScoped
public static boolean isRequestScoped(Binding<?> binding)
Returns true ifbinding
is request-scoped. If the binding is alinked key binding
and belongs to an injector (i. e. it was retrieved viaInjector.getBinding()
), then this method will also return true if the target binding is request-scoped.- Since:
- 4.0
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scopeRequest
public static <T> Callable<T> scopeRequest(Callable<T> callable, Map<Key<?>,Object> seedMap)
Scopes the given callable inside a request scope. This is not the same as the HTTP request scope, but is used if no HTTP request scope is in progress. In this way, keys can be scoped as @RequestScoped and exist in non-HTTP requests (for example: RPC requests) as well as in HTTP request threads.The returned callable will throw a
ScopingException
when called if there is a request scope already active on the current thread.- Parameters:
callable
- code to be executed which depends on the request scope. Typically in another thread, but not necessarily so.seedMap
- the initial set of scoped instances for Guice to seed the request scope with. To seed a key with null, usenull
as the value.- Returns:
- a callable that when called will run inside the a request scope that exposes the
instances in the
seedMap
as scoped keys. - Since:
- 3.0
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scopeRequest
public static RequestScoper scopeRequest(Map<Key<?>,Object> seedMap)
Returns an object that will apply request scope to a block of code. This is not the same as the HTTP request scope, but is used if no HTTP request scope is in progress. In this way, keys can be scoped as @RequestScoped and exist in non-HTTP requests (for example: RPC requests) as well as in HTTP request threads.The returned object will throw a
ScopingException
when opened if there is a request scope already active on the current thread.- Parameters:
seedMap
- the initial set of scoped instances for Guice to seed the request scope with. To seed a key with null, usenull
as the value.- Returns:
- an object that when opened will initiate the request scope
- Since:
- 4.1
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