org.springframework.web.context.support

Class ServletContextScope

  • java.lang.Object
    • org.springframework.web.context.support.ServletContextScope
  • All Implemented Interfaces:
    Scope, DisposableBean


    public class ServletContextScope
    extends java.lang.Object
    implements Scope, DisposableBean
    Scope wrapper for a ServletContext, i.e. for global web application attributes.

    This differs from traditional Spring singletons in that it exposes attributes in the ServletContext. Those attributes will get destroyed whenever the entire application shuts down, which might be earlier or later than the shutdown of the containing Spring ApplicationContext.

    The associated destruction mechanism relies on a ContextCleanupListener being registered in web.xml. Note that ContextLoaderListener includes ContextCleanupListener's functionality.

    This scope is registered as default scope with key "application".

    Since:
    3.0
    Author:
    Juergen Hoeller
    See Also:
    ContextCleanupListener
    • Constructor Summary

      Constructors 
      Constructor and Description
      ServletContextScope(ServletContext servletContext)
      Create a new Scope wrapper for the given ServletContext.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method and Description
      void destroy()
      Invoke all registered destruction callbacks.
      java.lang.Object get(java.lang.String name, ObjectFactory<?> objectFactory)
      Return the object with the given name from the underlying scope, creating it if not found in the underlying storage mechanism.
      java.lang.String getConversationId()
      Return the conversation ID for the current underlying scope, if any.
      void registerDestructionCallback(java.lang.String name, java.lang.Runnable callback)
      Register a callback to be executed on destruction of the specified object in the scope (or at destruction of the entire scope, if the scope does not destroy individual objects but rather only terminates in its entirety).
      java.lang.Object remove(java.lang.String name)
      Remove the object with the given name from the underlying scope.
      java.lang.Object resolveContextualObject(java.lang.String key)
      Resolve the contextual object for the given key, if any.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • ServletContextScope

        public ServletContextScope(ServletContext servletContext)
        Create a new Scope wrapper for the given ServletContext.
        Parameters:
        servletContext - the ServletContext to wrap
    • Method Detail

      • get

        public java.lang.Object get(java.lang.String name,
                                    ObjectFactory<?> objectFactory)
        Description copied from interface: Scope
        Return the object with the given name from the underlying scope, creating it if not found in the underlying storage mechanism.

        This is the central operation of a Scope, and the only operation that is absolutely required.

        Specified by:
        get in interface Scope
        Parameters:
        name - the name of the object to retrieve
        objectFactory - the ObjectFactory to use to create the scoped object if it is not present in the underlying storage mechanism
        Returns:
        the desired object (never null)
      • remove

        @Nullable
        public java.lang.Object remove(java.lang.String name)
        Description copied from interface: Scope
        Remove the object with the given name from the underlying scope.

        Returns null if no object was found; otherwise returns the removed Object.

        Note that an implementation should also remove a registered destruction callback for the specified object, if any. It does, however, not need to execute a registered destruction callback in this case, since the object will be destroyed by the caller (if appropriate).

        Note: This is an optional operation. Implementations may throw UnsupportedOperationException if they do not support explicitly removing an object.

        Specified by:
        remove in interface Scope
        Parameters:
        name - the name of the object to remove
        Returns:
        the removed object, or null if no object was present
        See Also:
        Scope.registerDestructionCallback(java.lang.String, java.lang.Runnable)
      • registerDestructionCallback

        public void registerDestructionCallback(java.lang.String name,
                                                java.lang.Runnable callback)
        Description copied from interface: Scope
        Register a callback to be executed on destruction of the specified object in the scope (or at destruction of the entire scope, if the scope does not destroy individual objects but rather only terminates in its entirety).

        Note: This is an optional operation. This method will only be called for scoped beans with actual destruction configuration (DisposableBean, destroy-method, DestructionAwareBeanPostProcessor). Implementations should do their best to execute a given callback at the appropriate time. If such a callback is not supported by the underlying runtime environment at all, the callback must be ignored and a corresponding warning should be logged.

        Note that 'destruction' refers to automatic destruction of the object as part of the scope's own lifecycle, not to the individual scoped object having been explicitly removed by the application. If a scoped object gets removed via this facade's Scope.remove(String) method, any registered destruction callback should be removed as well, assuming that the removed object will be reused or manually destroyed.

        Specified by:
        registerDestructionCallback in interface Scope
        Parameters:
        name - the name of the object to execute the destruction callback for
        callback - the destruction callback to be executed. Note that the passed-in Runnable will never throw an exception, so it can safely be executed without an enclosing try-catch block. Furthermore, the Runnable will usually be serializable, provided that its target object is serializable as well.
        See Also:
        DisposableBean, AbstractBeanDefinition.getDestroyMethodName(), DestructionAwareBeanPostProcessor
      • resolveContextualObject

        @Nullable
        public java.lang.Object resolveContextualObject(java.lang.String key)
        Description copied from interface: Scope
        Resolve the contextual object for the given key, if any. E.g. the HttpServletRequest object for key "request".
        Specified by:
        resolveContextualObject in interface Scope
        Parameters:
        key - the contextual key
        Returns:
        the corresponding object, or null if none found
      • getConversationId

        @Nullable
        public java.lang.String getConversationId()
        Description copied from interface: Scope
        Return the conversation ID for the current underlying scope, if any.

        The exact meaning of the conversation ID depends on the underlying storage mechanism. In the case of session-scoped objects, the conversation ID would typically be equal to (or derived from) the session ID; in the case of a custom conversation that sits within the overall session, the specific ID for the current conversation would be appropriate.

        Note: This is an optional operation. It is perfectly valid to return null in an implementation of this method if the underlying storage mechanism has no obvious candidate for such an ID.

        Specified by:
        getConversationId in interface Scope
        Returns:
        the conversation ID, or null if there is no conversation ID for the current scope