apptools.naming.dynamic_context module

Provider of a framework that dynamically determines the contents of a context at the time of interaction with the contents rather than at the time a class is written.

This capability is particularly useful when the object acting as a context is part of a plug-in application – such as Envisage. In general, this capability allows the context to be:

• Extendable by contributions from somewhere other than the original code writer

• Dynamic in that the elements it is composed of can change each time someone interacts with the contents of the context.

It should be noted that this capability is explicitly different from contexts that look at another container to determine their contents, such as a file system context!

Users of this framework contribute items to a dynamic context by adding traits to the dynamic context instance. (This addition can happen statically through the use of a Traits Category.) The trait value is the context item’s value and the trait definition’s metadata determines how the item is treated within the context. The support metadata is:

context_name: A non-empty string

Represents the name of the item within this context. This must be present for the trait to show up as a context item though the value may change over time as the item gets bound to different names.

context_order: A float value

Indicates the position for the item within this context. All dynamically contributed context items are sorted by ascending order of this value using the standard list sort function.

is_context: A boolean value

True if the item is itself a context.

class apptools.naming.dynamic_context.DynamicContext

Bases: apptools.naming.context.Context

A framework that dynamically determines the contents of a context at the time of interaction with the contents rather than at the time a context class is written.

It should be noted that this capability is explicitly different from contexts that look at another container to determine their contents, such as a file system context!