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:
  • Method Summary

    Modifier and Type
    Method
    Description
    void
    Deprecated.
    Deprecated in 5.4 with no replacement; not longer used by Tapestry.
    void
    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
    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 Details

    • 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:
    • decloak

      void decloak()
      Deprecated.
      Deprecated in 5.4 with no replacement; not longer used by Tapestry.
      Restores state previously hidden by cloak()}.
      Since:
      5.3
      See Also: