eclipse.dk - Eclipse RCP Under the Hood

Eclipse RCP Under the Hood Denne event er en kombination af en tutorial day og en live demonstration af en "full featured" Eclipse RCP applikation hvor udviklingen kommenteres on-the-fly. Medbring din laptop og prøv selv hvordan man forholdsvis let kan starte en Eclipse RCP applikation. Det er meget vigtigt at du allerede har Eclipse 3.6 installeret på maskinen. Følgende emner vil blive demonstreret / omtalt Eclipse RCP Arkitektur Konfiguration (OSGi console, plugin.xml, manifest.mf...) Packaging Extension Points UI / SWT / JFace Editors / Views Building and Testing

About Me
Tonny Madsen, Founder and Owner of The RCP Company
20 years of experience in system development in major companies
9 years experience as the Systems Architect of an 20+ MLoC project
8 years of experience with Eclipse and Eclipse RCP
Solutions Member of the Eclipse Foundation
Chairman of Eclipse.dk
Extern Lecturer at IT-University on Model Driven Development and Domain Specific Languages
Regular speaker at EclipseCon, Eclipse Summit, etc

Eclipse Architecture
Goals for the Eclipse architecture
Be able to host any number of 3 rd party applications
Scalability in terms of size and complexity of hosted applications
Alignment with native UI look-n-feel
Flexible architecture, structured around
Plug-ins – the basic unit of functionality
Extension points – the defined interfaces between plug-ins
This architecture allows for
Implementation of 3 rd party applications on top of the basic platform (Eclipse RCP)
Additional tools to be integrated in the platform
Integrated tools to be further extended

Eclipse Architectural Components JDT CVS WTP Datatools VE BIRT Mylyn PDE CDT Eclipse Platform Resources Workspace Help Update Team Web Server Filesystems Apache Search Navigator Intro Text Editors Eclipse RCP Run-time/OSGi SWT JFace Workbench Preferences Jobs ICU Commands Registry

The Basic RCP Components
In the Eclipse, everything is a plug-in including the run-time platform itself
It is a small kernel that represents the base of the platform
Built on top of OSGi
All subsystems built on the run-time platform follows the rules of plug-ins:
They are plug-ins themselves
RCP includes:
Component Management
Resources Management
Preferences
Workbench (include SWT and JFace)
RCP does not include the following:
Update
Help
This can be included from the Eclipse platform
Eclipse RCP Run-time/OSGi SWT JFace Workbench Preferences Jobs ICU Commands Registry

Your Typical RCP Application Application Platform Comm. Logging Help Update Auth. Auditing Apache Intro Base Add-on Add-on Add-on Add-on Debug Tools Data Model Eclipse RCP Run-time/OSGi SWT JFace Workbench Preferences Jobs ICU Commands Registry Add-on

Organizing the Platform
The software of an Eclipse system is based on the following terms:
Plug-ins – a plug-in is the basic unit of software
Fragments – a fragment is an add-on to an existing plug-in with additional functionality
Features – a feature is a number of plug-ins that is distributed and updated as a whole
Applications – an application is a Java class that implements a specific interface and is declared as such in the plug-in
Products – a product is a set of features or plug-ins along with the appropriate branding

Extension Points
Describe additional functionality that could be integrated with the platform
External tools extend the platform to bring specific functionality
Java Development Tooling (JDT) and Plug-in Development Environment (PDE) are external tools integrated with the platform
Extension points are used to
Add an implementation for a generic feature
Extend the workbench
Extend common object factory
Advantages:
Allows for late load and startup of plug-ins
Provides a common “registry” for most extensions like views, perspectives, commands, etc
Disadvantages:
Makes it harder to understand flow of control
ID Hell!
Extension points may have corresponding API interface
Describes what should be provided in the extension

The Role of Run-Time/OSGi
Dynamic module system for Java
Solves many of the problems of big applications
Late activation of code
Multiple versions of the same library
Eclipse is the reference implementation!

Workbench
Represents the desktop development environment
It contains set of tools for resource management
It provides common way of navigating through the resources
Multiple workbenches can be opened at the same time in individual windows

Eclipse User Interface Layers
4 Layers:
The Eclipse Workbench
Overall look-n-feel
JFace
Architecture-independent models
SWT
Platform independent API yet rather close to the metal
Native widgets
Platform dependent: Windows, Linux, Mac, Unix
The “Eclipse User Interface Guidelines” governs the look-n-feel of the workbench and JFace
Consequently (nearly) all Eclipse RCP based applications look the same!
Use the SWT Bible “The Definitive Guide to SWT and JFace” by Robert Harris and Rob Warner

SWT and the Native Widgets
SWT is short for ”The Standard Widget Toolkit”
SWT is a sub-project of the Eclipse project
SWT has a common API on all target platforms – the implementation is different
Base plug-in org.eclipse.swt contains only MANIFEST.MF plus some configuration files
A set of platform specific fragments implements all of SWT
org.eclipse.swt.win32.win32.x86 for 32-bit Windows on x86 (not Vista look-n-feel)
org.eclipse.swt.wpf.win32.x86 for Wista look-n-feel for 32-bit Windows on x86
SWT is a thin layer on top of the native widgets
Windows
Mac
Motif
GTK
SWT can easily be used stand-alone

SWT on Different Platforms

Working with SWT
SWT API is not as regular as Swing
The SWT site contains a large repository of “SWT Snippets” that demonstrates most of the abilities of SWT
To find leaks with graphical resources use sleak
It is possible to integrate SWT and Swing to a very large degree
Though expect problems with shortcuts and focus management

SWT Widgets
Basic
Button , Combo , Composite , Group , Label , Link , List , Menu , ProgressBar , Shell , Slider , Scale , Spinner , TabFolder , Table , Text , ToolBar , and Tree
Advanced
Browser , Canvas , CBanner , CCombo , CLabel , CoolBar , CTabFolder , DateTime , ExpandBar , GLCanvas , Sash , SashForm , ScrolledComposite , StyledText , SWT_AWT , TableCursor , and Tray
Other Sources – e.g. Nebula, Sourceforge.net
FormattedText , Gallery , Grid , and many more
The C... versions of Label , Combo and TabFolder are emulated and should normally be avoided if possible

SWT Widgets

The Basic Widget Hierarchy Widget Control Menu Item Button Label Composite List MenuItem TableItem TabItem Canvas Combo Form OleSiteClient Table, …

The Basic Widget Hierarchy
Widget
Top-level abstract super class for all widgets
Support for
arbitrary associated data
general event management
disposal management
Control
Top-level abstract super class for controls
Support for
foreground, background
border
content menu
focus management
layout management – layout, location and size
Composite
Control that can contain other controls
Support for layout management
A Composite must have a layout manager, or the child widgets will not be shown!

Using SWT Widgets
Common constructor form – e.g. new Text(parent, SWT.PASSWORD)
The parent
The style argument specifies the basic sub-function of the widget
Use Text controls for data values event when read-only, as this makes it possible to select and copy the value

Using SWT Styles
Second argument of all widget constructions – e.g. new Text(parent, SWT.PASSWORD)
The most use styles are
SWT.NONE – no style needed
SWT.LEAD , SWT.CENTER , and SWT.TRAIL - the alignment of text in labels, menus and buttons
SWT.ARROW , SWT.CHECK , SWT.PUSH , SWT.RADIO , and SWT.TOGGLE - the sub-type of a button
SWT.PASSWORD - Text is used for password entry
SWT.V_SCROLL , SWT.H_SCROLL , and SWT.NO_SCROLL – Table or Tree has vertical, horizontal or no scroll bar (3.4 and later)
Some special considerations regarding styles
Some style arguments cannot be changed once specified in the constructor (e.g. SWT.CHECK for a Button ), whereas others can (e.g. SWT.LEAD for Label )
Some style arguments have different meaning for different widgets –e.g. SWT.MULTI for Table and Text

Managing Composites ( Composite )
Children are added to a composite during the construction of the children
new Text(composite , SWT.BORDER)
Children are retrieved using
comp.getChildren()
Children are removed using
child.dispose()
Children can be moved in the parent using
child.moveAbove(otherChild)
child.moveBelow(otherChild)
When a composite is changed, remember to re-layout
comp.layout()
Setting the background of children of a composite:
comp.setBackgroundMode(SWT.INHERIT_DEFAULT)

SWT Layout Managers
The positioning and sizing of controls in a Composite (and subclasses) is performed using layout managers
SWT includes a rather complete set of standard layout managers
FillLayout and RowLayout : layout is a single row or column
GridLayout : layout in a grid with size constrains
FormLayout : layout in canvas with size and edge-to-edge constrains
Most GUI designer can handle these
A new layout manager can be created fairly easily created
computeSize : computes the “natural” size of the Composite
layout : lays out the controls of the Composite
public abstract class Layout { protected abstract Point computeSize(Composite composite, int wHint, int hHint, boolean flushCache); protected abstract void layout(Composite composite, boolean flushCache); }

Using the Grid Layout ( GridLayout )
Grid Layout is the most used layout manager in Eclipse
It works by adding the child widgets to the cells in a grid
Widgets are added in sequence
When using a Grid Layout, the parent uses the GridLayout and all children use GridData
final Composite composite = new Composite(parent, SWT.NONE); final GridLayout gridLayout = new GridLayout( 3, false ); composite.setLayout(gridLayout); label = new Label(composite, SWT.NONE); label.setText("Label"); text = new Text(composite, SWT.BORDER); text.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false , 2, 1 )); // …

Using the Grid Layout ( GridLayout )
The GridLayout class has two arguments
numColumns – the number of columns in the grid (defaults to 1)
makeColumnsEqualWidth – whether all columns in the grid have equal width (defaults to false )

Using the Grid Data ( Grid Data )
GridData specifies how a child widget is laid out in the parent grid
A GridData holds the following primary information
Grab Excess Space (horizontal and vertical) – describes whether the grid column or row should expand to grad any excess space (defaults to no grab)
Span (horizontal and vertical) – describes the number of cells the widget should span (defaults to 1 , 1 )
Alignment (horizontal and vertical) – placement of widget within the cells – one of SWT.BEGINNING , SWT.CENTER , SWT.END or SWT.FILL (defaults to BEGINNING , BEGINNING )
A GridData also contains information about indentation, minimum size and size hints
Don’t use the two-argument constructor!
1,1 2,1 2,2 C,C F,C E,E Horizontal grab No grab

Layout Managers for Tables and Trees
Tables and Trees have a layout the determine how columns are sized
TableLayout
Will only resize the columns the first time!
Applied to the Table or Tree
TableColumnLayout
Applied to the Composite of the Table or Tree
Column constrains saved as layout.setColumnData(column, constraint)
Both layout manager are based on the same column constraint objects:
ColumnPixelData – makes a column a specific width in pixels
ColumnWeightData – makes a column a specific percentage of the summed width

SWT Events
SWT events and listeners exist in two versions:
A simple very light-weight version
One event format and listener interface
A type-safe version
Multiple event formats and listener interfaces tailored to the specific use
The difference is illustrated in the following example
filter.addListener(SWT.KeyDown, new Listener() { public void handleEvent(Event event) { if (event.type == SWT.KeyDown) { //... } } }); filter.addKeyListener(new KeyAdapter() { @Override public void keyPressed(KeyEvent e) { //... } });

SWT Events
Key
KeyDown , KeyUp , HardKeyDown , HardKeyUp
Mouse
MouseDown , MouseUp , MouseMove , MouseEnter , MouseExit , MouseDoubleClick , MouseHover , MouseWheel
Control
Paint , Move , Resize , Dispose
Selection
Selection , DefaultSelection
Focus
FocusIn , FocusOut
Tree and Table
Expand , Collapse , EraseItem , MeasureItem , PaintItem
Shell
Iconify , Deiconify , Close , Activate , Deactivate
Menu
Show , Hide , Arm , MenuDetect
Basic Controls
Modify , Verify , SetData , Settings
Drag-n-Drop
DragDetect
Misc
Help

Lab Exercise
Create a view with the following look using simple SWT controls
GridLayout , GridData
Label , Text , Button
… addSelectionListener(…)
Another extra lab for the fast ones:
add “stuff” to the lab to only allow “a” and “b” in the text field
and to only allow more “a” than “b”!
Use a Verify listener
public class View extends ViewPart { public void createPartControl(Composite parent) { Composite top = new Composite(parent, SWT.NONE); // Add something here… } public void setFocus() { } } GridLayout with 2 columns Label Text FILL aligned + grab Button spans two columns, RIGHT aligned SelectionListener that prints current text of Text control

Forms UI
A newer addition of the look-n-feel of the Eclipse workbench is the Forms UI in org.eclipse.ui.forms .
Provide a Web browser like look-n-feel to forms
PDE is a good example of the increasing use of this new technology
Have some of the same problems as seen in ordinary Web applications: extensive use of the mouse! Normally not welcome in office applications

More Information
“ Eclipse User Interface Guidelines: Version 2.1”
http:// www.eclipse.org/resources/resource.php?id =162
The Look-n-Feel guidelines for Eclipse – heavily influenced by the corresponding Microsoft Windows Look-n-Feel guidelines
SWT home
http:// www.eclipse.org/swt /
SWT versus Swing
http://www.developer.com/java/other/article.php/2179061
“ Using SwingRCP (instead of SWT) in RCP”
http://www.eclipsezone.com/eclipse/forums/t104467.rhtm l
A discussion of different ways to integrate Eclipse RCP and Swing
“ The Definitive Guide to SWT and JFace” by Robert Harris and Rob Warner (ISBN: 978-1590593257)
As it says – “The Definitive Guide…” – and needed due to the pure javadoc of SWT
“ SWT Snippet” Repository
http:// www.eclipse.org/swt/snippets /
A large repository of sample code for most uses of SWT!

More Information
“ Plug a Swing-based development tool into Eclipse”
http://www-128.ibm.com/developerworks/opensource/library/osswing/
“ Eclipse Forms: Rich UI for the Rich Client”
“ Custom Drawing Table and Tree Items”
“ Using Images in the Eclipse UI”
“ Rich clients with the SWT and JFace”
http://www.javaworld.com/javaworld/jw-04-2004/jw-0426- swtjface.html?page=2
“ SWT: The Standard Widget Toolkit”
“ Understanding Layouts in SWT”
http://www.eclipse.org/resources/resource.php?id=242
A good overview of the different basic layouts in Eclipse.

More Information
“ Drag and Drop in the Eclipse UI”
“ Adding Drag and Drop to an SWT Application”
“ Eclipse Data Binding Test Drive” (webinar)
“ Swing/SWT Integration”
“ Eclipse Forms: Rich UI for the Rich Client”
http://www.eclipse.org/articles/Article-Forms/article.html
The Forms UI explained with some good examples

eclipse.dk - Eclipse RCP Under the Hood

by Tonny Madsen on Nov 12, 2010

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eclipse.dk - Eclipse RCP Under the Hood — Presentation Transcript