Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements.  See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License.  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

Navigational State and Jetspeed Path Proposal

The URL path is a common way to track navigation state.
Pluto does this, as does Websphere.

Jetspeed has the concepts of folders, and pages.
Folders contain pages or more folders. A typical tree hierarchy.
Users can navigate through the portal by specifying folders and pages.
Jetspeed Folders and Pages also represent navigational state, 
however they are not directly covered by the Portlet specification.

We are proposing specifying the Jetspeed Paths and Folders directly in the URL path, not the request parameters.
This solves the issues of locating the correct page at all times, as long as Jetspeed rewrites the URL.
The Jetspeed URL rewriter must always rewrite the Page into the URL.
Of course there are still default pages for users, which do not need to be in the URL.

Example URLs:

http://localhost/portal/jetspeed/nfl/afc/chiefs/passing-stats.psml

where "nfl/afc/chiefs/passing-stats.psml" is the complete path.
and passing-stats is either a page or folder.
".psml" helps the profiler figure out that its a page.
Otherwise it will first look for a page with that name, then a folder.

NOTE: we are not using path pairs

This will introduce problems for other path params that require pairs.
Most notably, Navigation State.
Navigation State is currently implemented with Pluto-like pairs of parameters.
In order for this to continue to function, we would enhance the path parsing code to find 
the end of the path locator and then start parsing.
Navigational state must be written after the folder/page path.

Window Navigational State will be enhanced:

1. abstract all navigational state to use interfaces
2. provide 2 implementations
    1. URL path state
    2. session-based state
    note: i don't think its possible to use request params to keep nav state