Classes

From LongJump Support Wiki
Revision as of 00:34, 3 June 2011 by imported>Aeric

Designer > Logic > Classes

A class is a standard Java class. Consider writing classes to create business logic that is not provided by the basic building blocks of the platform. Learn more: Classes in the Developer Suite

There are two types of classes:

  • Working classes
  • Controller classes

In most cases, a page communicates with a class through a controller class which creates an instance of a worker class. For details, see Working with Pages and Classes. You can instantiate a class directly in a page. However, this is considered a bad practice.

About APIs

You can make Java API calls in the Java code in a class. The following Java API classes are implicitly imported into classes:

You can also call functions.

You can create an instance of a class in Java code.

There are some restrictions on the things you can do in a Java class, as described in Governors on Java Code .


Manage Classes

From the Classes page, a number of features are provided to view, create and manage classes.

To view Classes:

  1. Click Designer > Logic > Classes
  2. Optionally, choose a View; In addition to the All Records view, the following views are available:
    • Platform Generated Classes - Displays a list of Classes generated by the LongJump Platform
    • User Created Classes - Displays a list of Classes created by Users
  3. Use the action buttons:

Add a Class

Prerequisite Before you create a class, you need to decide what package to put it in. Here are a few notes to help you make that decision:

  • Packages let you organize classes into different directories according to their functionality, their usability, or any other category that makes sense. (The only rule is that classes in one package have a qualitatively different kind of functionality compared with those in another package.)
  • Packages help to avoid class name collision. (The same class name can be used in different packages.)
  • Classes in the same package can access each others package-protected fields and methods, as well as their public members, without doing an import. So classes that cooperate with each other extensively generally belong in the same package.
  • Classes that are part of a different package can be accessed with an import declaration.

To add a class:

  1. Click Designer > Classes
  2. Click [New Class]
  3. Fill in the class properties.
  4. Click [Next]
    A class template appears.
  5. Provide the code for the class.
  6. Click [Save]

Class properties

Package
The package name
  • The platform supplies this part: com.platform.{namespace},
    where {namespace} is defined in the Developer Configuration settings of the current tenancy.
  • You supply this part: {packagename}
The result is the fully-qualified package path for the class: com.platform.{namespace}.{packagename}
Class Name
The name of the class. Must consist of alphanumeric characters (a-z,A-Z,0-9) or underscores (_). Must start with an alphabetic character (a-z,A-Z) or underscore (_).
Global Class
Checkbox
If checked, this class is a Global Class
If unchecked, this class is available to users in the current tenancy, only
Java code
Enter Java code in the text area.

Edit a Class

To edit a class:

  1. Click Designer > Logic > Classes
  2. Click the name of the class to edit
  3. Click [Edit]
  4. Edit the Java code in the text area
  5. When done, click [Save]

Delete a Class

To delete a class:

  1. Click Designer > Logic > Classes
  2. Click the name of the class to delete
  3. Click [Delete]

Editing Classes in Eclipse

Use the Eclipse Plug-In to add, edit or delete classes.