BeanInfo reference

Created by Stefan Rennick Egglestone 2005-11-16
Last updated by Chris Greenhalgh 2005-11-28

Introduction
Using the BeanDescriptor
Using PropertyDescriptors
Supplying an icon

Introduction

The provision of one BeanInfo class per component is one method which can be used to indicate to ECT the existence of that component. For more information, see the Component Development Guide. BeanInfo classes can either be auto-generated from a component class, or can be manually constructed by a developer. This reference guide is intended for those who wish to use this latter method, and describes the information about a component that can be specified in a BeanInfo class.

Using the BeanDescriptor

Classes which implement the BeanInfo interface must provide a method which can return a java.beans.BeanDescriptor) object which describes the bean. Information included in a generic bean descriptor includes:

shortDescription

expert (a boolean flag)

hidden (a boolean flag

preferred (a boolean flag)

an open set of named attributes

the bean's class (java.lang.Class)

the bean's customizer class if any (java.jang.Class)

BeanInfo classes representing components should use these properties and attributes as following:

displayName should be used as the normally presented bean name. It is displayed, for example, in the tree presented in the capability editor

shortDescription should be a brief description of the component. It is displayed, for example, in a line of text at the bottom of the capability browser, and as a tooltip in the capability browser. Optionally, it can be formatted in HTML.

preferred, expert and hidden should not normally be used

attribute "classification" specifies where the component should appear in the capability browser; sub-folders names are separated by '/'. For example, "Hardware/Input" for an input device interface component. See

component classifications list

attribute "htmlDescription" can be used to specify any length documentation necessary for a component.
attribute "DefaultInputProperty" can be used to specify the name of a property to be used a the (only) default input, for example in the display editor.
attribute "DefaultOutputProperty" can be used to specify the name of a property to be used a the (only) default input, for example in the display editor.

See Component documentation guide for more information about how some of these properties and attributes are used by ECT.

Using PropertyDescriptors

Each component property is described by a Property Descriptor (java.beans.PropertyDescriptor). This identifies the properties "external" name, its set and get methods (normally both, or just a get method for read-only properties) and the property's type (java class, normally automatically determined). Property descriptors can contain additional information which may be used by ECT. In particular

shortName should be set to a short name for the property

preferred should be set to true for end-user configurable (normally experience-time) properties

expert should be set to true for anciliary properties not essential to normal configuration or use

Supplying an Icon

A Bean Info can provide an icon for its bean, in one or more combinations of 16x16 or 32x32 and mono or colour. 16x16 colour is recommended as a minimum, with a transparent background.