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The Concepts pages define concepts and elements used in the Eclipse Scout Framework.
Big Picture - Main Architecture of Scout
Scout is a framework for creating modern business applications. Such applications are typically separated into multiple tiers where each tier is responsible for a specific part of the application like presenting information to the user or processing business logic and persisting data.
Scout solves these requirements by providing a separation of such tiers out of the box. The two main tiers of Scout are the client part and the server part.
Scout is also a framework, which is simple to use but yet flexible. This is achieved, amongst other things, by using a stable platform as base, namely Eclipse / Equinox. By using this base on both the client and the server side, it becomes possible to use the same technologies and tools for creating the server and the client part. Even though these tiers are separated, there is no need to use different Eclipse workspaces or even different developers for each tier. One developer is able to create a multi tier application in one Eclipse workspace and still has a strict separation of client and server thanks to OSGI/Equinox.
Another thing that makes it so simple is the communication between these tiers. There is no need to explicitly define webservice and exchange WSDLs in the same application, only to show some information on a dialog (not implying that it would not possible to do so, it actually is!). Instead OSGi services are used where only an interface is sufficient. That interface for a service including the data transfer objects (DTO) is known on client and server side. This is achieved by having these interfaces in a shared part. With that mechanism it is possible to provide a service tunnel, which actually is one webservice tunneling every OSGi service call from client to server.
A Scout project is composed of different Eclipse plug-ins (each plug-in is an Eclipse Project).
- Client Plug-In (eg
- Shared Plug-In (eg
- Server Plug-In (eg
Since the Scout runtime relies on a strict separation of business code and presentation code additional plugins are provided where GUI specific code is placed. Depending on the GUI implementation these plugins can be one of the following:
- SWT UI Plug-In for native desktop applications (eg
- Swing UI Plug-In for individual desktop applications (eg
- Rap UI Plugin for web (2.0) applications (eg
The image "Plugin-Set of a Scout Application" shows how the plug-ins are organized. In the above part of the image you can see the plug-ins of a typical scout application: client, shared, server and the ui-plugin. In to bottom part there are the equivalent plug-ins of the Scout Runtime Framework. All these plug-ins follow strict dependency rules which are represented by the arrows. The application's server plug-in for example does not know anything about the client it only knows the shared plug-ins and the server plugin of scout.
The Scout SDK relies on the following principles to recognize and display the structure of a Scout project:
- Each plug-in project is marked to be of "Scout Nature" in its .project file. This is handled by the Scout SDK for you if you create a new Scout project. You can also add an existing plug-in project to a Scout project via the "Import Plugin..." menu in the Scout SDK. However, you then still need to handle the bundle dependencies and naming convention manually (see below).
- Bundle dependencies: A plug-in project is represented as a client component (orange box) if it depends on the org.eclipse.scout.rt.client bundle. Similarly, a shared or server component depends on the corresponding Scout RT bundle. Also, both the client and server bundles should depend on the shared bundle.
- Naming convention: A Scout project has a project name (e.g. my.project.name) and an optional project postfix (e.g. core). The plug-in projects then follow the naming pattern projectName.[client|shared|server].postfix. The full name of the client bundle then would be my.project.name.client.core.
Overview of the concept pages
- Client/Server Communication
- Service Tunnel
- Session Handling
- Client part
- Separation of UI and GUI
- Threading and Jobs
- Component Model
- Server part
- Providing data for the client
- Accessing persistent data
- Webservice (JAX-WS) support
- Server Side Equinox
- Transaction Handling
- Shared part
- Security Principles of Scout
- Scout SDK