Eclipse Plug-in Developer Guide (Galileo) - IIntroContentProvider (Eclipse Platform API Specification)

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Eclipse Platform
Release 3.5

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org.eclipse.ui.intro.config
Interface IIntroContentProvider

All Known Subinterfaces:: IIntroXHTMLContentProvider

All Known Implementing Classes:: AlwaysWelcomeCheckbox

public interface IIntroContentProvider

A content provider for dynamic intro content. It is initialized with the content provider site because a typical content provider would need to update its contents dynamically at runtime. And so, the site can be informed of a need to redraw its content through a call to its reflow(..) method.

The life cycle of an IIntroContentProvider is as follows:

a content provider is defined in the Intro content markup file (ie: introContent.xml file) as follows:
<contentProvider id="roles" class="x.y.z.ContentProvider">
<text>Some alternate text for dynamic content</text>
</contentProvider>
This defines the content provider as part of the intro content for that page.
the content provider class is created when the page that contains this provider is loaded. It is only created once in the life cycle of an open Intro view, ie: the class instance is cached and only disposed of when the intro view is closed.
init() is called to initialize the instance of the class on load of the page. This is where the provider site can be cached for later reuse.
createContent() is then called to give the content provider a chance to generate the dynamic content. This is when the dynamic content can be cached for later reuse when the same page is shown again.
it is important to note that there is a difference between when the createContent() is called in the case of SWT and HTML presentations. The HTML presentation is dynamic html generated on the fly each time an Intro page needs to be displayed. SWT presentation on the other hand, is based on SWT forms widgets, and for performance, each page is only created once and cached in a pageBook for re-use. With this in mind, createContent() is called every time a page is shown in the case of HTML presentation. Whereas it is only called once in the case of the SWT presentation. This is why createContent() should not be used as a means of refreshing content. Content should only be created once during this method call, and cached for later re-use. If a refresh is needed, then reflow() should be called on the contentProviderSite when the appropriate event happens.
finally, when the intro view is closed, dispose will be called on the content provider to give it a chance to dispose of any resources.

Since:: 3.0.1

Method Summary

void createContent ( String id, Composite parent, FormToolkit toolkit)
          Creates SWT content in the provided Composite.

void createContent ( String id, PrintWriter out)
          Creates HTML content in the provided PrintWriter.

void dispose ()
          Dispose of the ContentProvider.

void init ( IIntroContentProviderSite site)
          Initializes the content provider.

Method Detail

init

void init(
IIntroContentProviderSite site)

Initializes the content provider. An IIntroContentProviderSite is passed, which will be called on to recompute or layout the content when the content becomes stale.

Parameters:: site - the site of this IIntroContentProvider

createContent

void createContent(
String id,
                   
PrintWriter out)

Creates HTML content in the provided PrintWriter. This content will be included in the generated HTML page when embedded HTML widget is used to render intro content.

Parameters:: id - the unique identifier of the content element. The same content provider class can be reused for several elements and the id can be used to tell them apart.; out - the output print writer to generate HTML content into

createContent

void createContent(
String id,
                   
Composite parent,
                   
FormToolkit toolkit)

Creates SWT content in the provided Composite. This method is called when Eclipse Forms are used to render intro content.

Parameters:: id - the unique identifier of the content element; parent - the parent composite that should be used when creating SWT widgets; toolkit - the form toolkit that should be used when creating new widgets

dispose

void dispose()

Dispose of the ContentProvider. This will only be called when the Intro view is closed. In other words, the content provider will not be disposed of until the last possible minute. This gives the implementor the chance to cache content and avoid regenerating content on every page switch.