Expresso

Package containing all of the objects for Expresso's Cache Manager, a general-purpose system for in-memory caching.

The caching system has many features such as built in Memory limitation, named caches, ordered and undered caches , and many other features. It is designed to be highly efficient for quick retrieval of Objects without requiring a network round trip to a database.

This package contains the object defining the "Controller" object, an important component of Expresso that should be used to encapsulate all user interaction sequences.

Controllers are the guts Expresso's logic system. You derive your own controller class from DBController to automatically get features such as built in per-state security.

The DataObjects package contains a set of interfaces and base classes that give the ability to provide a unified object approach to various data sources. It is roughly based off of the older DBObject which was less flexible, only allowed one dbobject per table, and was only JDBC capable.

This package contains implementations and helper classes of DataObjects that pertain to JDBC data sources only.

NOTE: The interfaces in this package are of beta quality. They are still being tested and worked on, and thus may chance in the near future.

This package contains a public preview of future configuration code. In the near future, all database configurations except for user-specific information will be stored here.

The classes themselves are mainly digester related classes, while the .xml files are the actual configuration files for various databases.

Ancestor objects for all Database Objects and Schemas.

Database Objects are probably the single most used part of Expresso. They provide Object Relational mapping capabilities to a database table. They also give you the ability to embed capabilities such as validation logic, master-detail relations, and more.

Classes that define "Jobs" or server-side tasks that are run asynchronously to the user's web browser.

They are usually run by the JobHandler, of which you can have more than one JobHandler running to get greater job throughput.

Base classes for all JavaCorporate servlets.

Straight servlets by and large are no longer used within Expresso as such. We strongly encourage you to create your web-application based upon Expresso's Controller objects rather than servlets since they give you basic flow control, subdivision of tasks, and built-in per-state security.

Controllers that are optional to Expresso. Mostly for administration.

This package contains an abundance of Expresso specific tags.

Some of these tags closely duplicate the functionality of Expresso-aware struts tags. It will be up for you to decide which to use. The Expresso tags are often easier to use than the corresponding Struts tags, but may not offer as much flexibility, especially in the area of javascript code. It is up to you to decide.

This package contain bean classes and digester rule classes for loading the expresso runtime configuration file, and expresso component metadata.

This package contains an exception hierarchy that can be thrown by the Expresso runtime system..

This package contains classes that should not be normally used or referenced outside of the kernel package hierarchy.

This package provide classes that provide the core logic for managing the Expresso configuration hierarchy. It can be expanded upon via Swing Clients, Web applications, etc.

If you are 'outside' of the hierarchy and need to be able to reach into it for management or backwards compatibility, use the ExpressoRuntimeMap to retrieve an instance of the various configuration runtimes that are available on the system.

This package contains bean classes that are created/loaded by the Digester system to represent metadata for Expresso components.

This package contains utility classes that assist in the operation of the kernel package and any other Expresso classes.

The Async processor framework is designed to handle situations where an Expresso Job is not appropriate because you do want the results sent back to the user when it is done. Instead, the AsyncProcessor queues items up and processes them as fast as it can sending status and result objects back to the "Ticket Holder" when status is requested. These async processes have also been called "Active Objects."

See the EDG chapter on Async Processing for a more detailed description of the purpose of this package.

This package contains the various State objects that make up the "Model" of the DBMaint controller. These states can be extended and customized to give DBMaint specific custom behaviours.

DBMaint is a generic database-editing web user interface. It provides all basic needs for add/update/delete/searching records for data tables. It interacts directly with DBObjects.

Contains classes that assist in unit testing using JUnit and Cactus testing.

For client side unit testing you should create a single test suite that creates Expresso at the beginning and drops it at the end. You can then use things like DBUnit to create/delete individual entries if needed, but the table creation is just too long for practical testing.

The other class of import is TestSystemInitializer. It allows you to specify a scratch database context that you can use, which, of course, is highly advisable since the unit tests are highly destructive.

This package provides for a 'validation framework'. This framework is provided for a specific group of problems described as follows:

1. User enters some information to perform some sort of action, let's say to unsubscribe from a mail list.
   
   
2. The validation framework then sends a confirmation email to the user that includes a clickable URL. This URL contains a 128-bit random number.
   
   
3. The user clicks on the random number. The framework then looks up that random number and dispatches the request to the appropriate ValidationHandler class.
   
   
4. The validation handler then performs the appropriate actions and displays the final message to the user.

You can see this system in action in Expresso's registration system in: com.jcorporate.expresso.services.controller.RegistrationController