Package org.apache.tapestry5.services

Interface Environment

  • All Known Implementing Classes:
    EnvironmentImpl
    public interface Environment
    Provides access to environment objects, which are almost always provided to enclosed components by enclosing components. Environmental services are a form of very late binding. The Environment acts like a collection of stacks. Each stack contains environmental objects of a given type. Most often, a stack has zero or one elements, but on occasion, a particular component will push an override onto the stack for the benefit of the components it encloses.
    See Also:
    Environmental, EnvironmentalShadowBuilder

    • Method Summary

      All Methods Instance Methods Abstract Methods Deprecated Methods 
      Modifier and Type Method Description
      void cloak()
      Deprecated.
      Deprecated in 5.4 with no replacement; not longer used by Tapestry.
      void decloak()
      Deprecated.
      Deprecated in 5.4 with no replacement; not longer used by Tapestry.
      <T> T peek​(Class<T> type)
      Peeks at the current top of the indicated stack.
      <T> T peekRequired​(Class<T> type)
      Peeks at the current top of the indicated stack (which must have a non-null value).
      <T> T pop​(Class<T> type)
      Removes and returns the top environmental object of the selected type.
      <T> T push​(Class<T> type, T instance)
      Pushes a new service onto the stack.

    • Method Detail

      • peek

        <T> T peek​(Class<T> type)
        Peeks at the current top of the indicated stack.
        Type Parameters:
        T - the type of environmental object
        Parameters:
        type - class used to select the object
        Returns:
        the current object of that type, or null if no service of that type has been added

      • peekRequired

        <T> T peekRequired​(Class<T> type)
        Peeks at the current top of the indicated stack (which must have a non-null value).
        Type Parameters:
        T - the type of environmental object
        Parameters:
        type - class used to select the object
        Returns:
        the current object of the specified type
        Throws:
        RuntimeException - if no service of that type has been added

      • pop

        <T> T pop​(Class<T> type)
        Removes and returns the top environmental object of the selected type.
        Type Parameters:
        T - the type of environmental object
        Parameters:
        type - class used to select the object
        Returns:
        the object just removed
        Throws:
        NoSuchElementException - if the environmental stack (for the specified type) is empty

      • push

        <T> T push​(Class<T> type,
           T instance)
        Pushes a new service onto the stack. The old service at the top of the stack is returned (it may be null).
        Type Parameters:
        T - the type of environmental object
        Parameters:
        type - class used to select the object
        instance - the service object
        Returns:
        the previous top service

      • cloak

        void cloak()
        Deprecated.
        Deprecated in 5.4 with no replacement; not longer used by Tapestry.
        Hides all current environment values, making the Environment object appear empty, until a call to decloak()} restores the original state.
        Since:
        5.3
        See Also:
        TapestryConstants.RESPONSE_RENDERER