PEAK Release 0.5 alpha 1 |
PEAK Release 0.5 alpha 1 |
|
|
Copyright (C) 1996-2002 by Phillip J. Eby and Tyler C. Sarna. |
Copyright (C) 1996-2003 by Phillip J. Eby and Tyler C. Sarna. |
All rights reserved. This software may be used under the same terms |
All rights reserved. This software may be used under the same terms |
as Zope or Python. THERE ARE ABSOLUTELY NO WARRANTIES OF ANY KIND. |
as Zope or Python. THERE ARE ABSOLUTELY NO WARRANTIES OF ANY KIND. |
Code quality varies between modules, from "beta" to "experimental |
Code quality varies between modules, from "beta" to "experimental |
pre-alpha". :) |
pre-alpha". :) |
|
|
|
|
Package Description |
Package Description |
|
|
PEAK is the "Python Enterprise Application Kit". If you develop |
PEAK is the "Python Enterprise Application Kit". If you develop |
from TransWarp, and repackages them as an enterprise software toolkit. |
from TransWarp, and repackages them as an enterprise software toolkit. |
Where TransWarp emphasized techniques like generative programming and |
Where TransWarp emphasized techniques like generative programming and |
aspect-oriented programming, PEAK emphasizes enterprise applications, |
aspect-oriented programming, PEAK emphasizes enterprise applications, |
and hides the computer scienece stuff "under the hood", so you can focus |
and hides the computer science stuff "under the hood", so you can focus |
on building your application. |
on building your application. |
|
|
PEAK tools can be used with other "Python Enterprise" frameworks such as |
PEAK tools can be used with other "Python Enterprise" frameworks such as |
Zope and the Python DBAPI to construct web-based, GUI, or command-line |
Zope, Twisted, and the Python DBAPI to construct web-based, GUI, or |
applications, interacting with any kind of storage, or with no storage |
command-line applications, interacting with any kind of storage, or with |
at all. Whatever the application type, PEAK can help you put it together. |
no storage at all. Whatever the application type, PEAK can help you put |
|
it together. |
|
|
|
Package Features |
|
|
|
As of version 0.5a1, PEAK features include: |
|
|
|
* A component binding framework that makes it easy to parameterize |
|
components and thus more easily combine and "wire" them together. |
|
|
|
* A comprehensive configuration framework that allows accessing |
|
"utilities" and "configuration properties" in context. Properties |
|
and utilities can be loaded or computed on demand, supplied by rules, |
|
defined in configuration files or code, in a supplied or custom |
|
format. Properties and utilities are contextual and can be safely |
|
acquired from parent/context components automatically. System-wide |
|
(per Python interpreter), application-wide (per running application |
|
within an interpreter) and per-component configuration settings |
|
are available. |
|
|
|
* Naming system/framework that's midway between J2EE's JNDI and CORBA's |
|
cosNaming in features, but much easier to use and extend than either |
|
of those systems. |
|
|
|
* A storage management and persistence system, including: |
|
|
|
- Atomic, multi-database transactions with two-phase commit. |
|
|
|
- "Data Manager" class framework for persistence management, that |
|
allows you to separate business logic from storage implementation. |
|
If you can write a few simple methods like "load" and "save" for |
|
a given object type and storage approach, you can create your own |
|
"DM" components. You can think of a DM as an advanced form of |
|
Python "shelve", that supports references to other objects, |
|
transactions, arbitrary back-end storages, and caching. |
|
|
|
- "Stackable" data managers: one DM might serialize a set of objects |
|
to XML, which could then be stored in a database record by another |
|
DM, and then the database record might be implemented via a DM |
|
that writes to disk files! Each DM only needs to know how to |
|
manipulate objects offered by the next-level DM, not the details |
|
of the next DM's implementation, so all the DM's are potentially |
|
replaceable with alternate storage mechanisms. |
|
|
|
- RDBMS and LDAP connection framework based on the Python DBAPI, |
|
that handles data type conversions (via the configuration |
|
framework) and seamlessly integrates with the transaction system |
|
and naming services framework. DB Connections can be accessed |
|
by name or URL, and bound as default collaborators or utilities |
|
for access by other application components. |
|
|
|
* CASE/modelling tools: PEAK includes APIs to read object |
|
models created in the XML-based XMI format. Many open-source and |
|
commercial modelling tools support XMI, inlcuding Argo/Poseidon and |
|
MagicDraw UML. PEAK includes pre-built support for UML versions 1.3 |
|
through 1.5, CWM 1.1, and MOF 1.3.1, using XMI versions 1.0 through 1.2. |
|
Also included, a MOF->Python code generator, which was used to generate |
|
the UML and CWM support, and which you can use to generate support for |
|
other modelling languages based on the MOF. |
|
|
|
For the specifications of XMI, MOF, CWM, and UML, visit: |
|
http://www.omg.org/technology/documents/modeling_spec_catalog.htm |
|
|
|
* A domain modelling framework for creating "business object models" |
|
with unidirectional and bidirectional associations, generated |
|
getters/setters and validators for fields, etc., and all necessary |
|
persistence support for use with the PEAK storage framework. |
|
|
|
The business object framework supplies structural metadata about |
|
classes built with it, so you can query a class for its fields and |
|
links, and their names, types, etc. This can be useful for |
|
implementing model-driven storage or user interfaces. And the |
|
metadata is aligned with the MOF, so generating MOF, UML, or CWM |
|
from PEAK models (and vice versa) is possible (although |
|
not yet implemented for anything but MOF->PEAK). |
|
|
|
* AOP and SOP: PEAK allows you to separate concerns as modules, then |
|
combine the modules via a "module inheritance" technique. This |
|
lets you define a generated business object model as a |
|
"structural" concern, and then combine it with a "behavioral" |
|
concern. This is as simple as writing classes that just contain |
|
what you want to add, and then telling PEAK that your new module |
|
"inherits" from the generated module. |
|
|
|
|
|
Known Issues and Risks of this Version |
|
|
|
This is ALPHA software. Although much of the system is extensively |
|
tested by a battery of automated tests, it may contain bugs, especially |
|
in areas not covered by the test suites. Also, many system interfaces |
|
are still subject to change. |
|
|
|
PEAK includes early copies of Zope X3's 'Interface' and 'Persistence' |
|
packages, which have since changed names in their official releases, |
|
and have had - and will continue to have - significant implementation |
|
changes. Complete interoperability with Zope X3 is therefore currently |
|
at risk. We are waiting until the pending refactoring of Zope 3's |
|
interface package is complete before upgrading from 'Interface' to |
|
'zope.interface'. Also, the ZODB persistence package is undergoing |
|
some changes that may make it less useful for PEAK, and we may be |
|
forced to "fork" and/or create our own C-level persistence support. |
|
This may be clearer once ZODB4 and/or Zope 3 reach their next release. |
|
|
|
Documentation at present is limited, and scattered. The principal |
|
documentation is an API reference generated from the code's lengthy |
|
docstrings (which usually contain motivating examples for using that |
|
class, method, or function). The mailing list and its archives |
|
provide a wealth of information on actual usage scenarios, |
|
recommended approaches, etc. There is also the beginnings of a |
|
tutorial on using the component binding package. |
|
|
|
|
|
Third-Party Software Included with PEAK |
|
|
|
The 'kjbuckets' module is Copyright Aaron Watters and contributors; |
|
please see the 'src/kjbuckets/COPYRIGHT.txt' file for details of its |
|
license. |
|
|
|
The 'Interface' and 'Persistence' packages are Copyright Zope Corporation |
|
and contributors; please see the 'LICENSE.txt' files for details of their |
|
licenses. |
|
|
|
|
Installation Instructions |
Installation Instructions |
|
|
See the INSTALL.txt file. |
Please see the INSTALL.txt file. |