ecologylab.appframework
Class Scope<T>

java.lang.Object
  ecologylab.appframework.Scope<T>

Direct Known Subclasses:

ClassRegistry

public class Scope<T>
extends java.lang.Object

A lexical Scope of bindings from names to values. Lexical Scopes can be nested. However, bind operations are only performed on the current Scope. Lookup operations chain through parents, as necessary, when a binding is not found locally.

These replace statics and are much more flexible.

Constructor Summary

Scope()

Scope(Scope<T> parent)

Method Summary

T	bind(java.lang.String name, T value) Bind an object to a name.
boolean	isBound(java.lang.String key)
T	lookup(java.lang.String name) Lookup an object in this.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Scope

public Scope()

Scope

public Scope(Scope<T> parent)

Method Detail

bind

public T bind(java.lang.String name,
              T value)

Bind an object to a name.

Parameters:

name -

value -

Returns:

Previous value, or null if there wasn't one.

lookup

public T lookup(java.lang.String name)

Lookup an object in this.

Parameters:

name -

Returns:

The object associated with this name, found in the registry, or null if there is none.

isBound

public boolean isBound(java.lang.String key)

Parameters:

key -

Returns:

true if there is already a binding for key in this Scope.