Eclipse as a Web 2.0 Application Position Paper

Transcription

1 Eclipse Summit Europe Server-side Eclipse October 2006 Eclipse as a Web 2.0 Application Position Paper Automatic Web enabling of any RCP-application with Xplosion Introduction If todays Web 2.0 application are being discussed, the term Web 2.0 is often used in conjunction with AJAX, Google Maps or other concrete solutions. On the other hand in general Web 2.0 means to leave the existing way of HTML, to achieve Rich Clients with the look & feel of locally installed programs, which are part of a client/server system. Let's go whole hog. With this motto in mind Eclipse can directly be used to establish a Client/Serversystem for Surf & Work. Some of such Web 2.0 applications are based on the paradigma, that the existing infrastructure should not be changed. To accomplish this, these applications use standard web browsers together with their capabilities to process HTML pages with possible embedded Java Script code. Though this has an advantage; this approach has as well weighty disadvantages: Not everything, what is provided by the operating system can be completely exploited. Nevertheless many applications require exactly this. With AJAX for example it is possible to create quickly simple user interfaces. On the other hand complex UI s lead soon to trouble because of the limitations of the http-protocol. The main reason is, that the communication between client and server is triggered only by the client. AJAX simulates the inverse way by simulating the necessary life cycle by a polling technique, which never can be as effective as in tight coupled systems like for instance AWT or SWT. In such API s the life cycle allows that the application can trigger instantiation and method calls in the user interface. This article describes the way, how Eclipse based Web 2.0 can be implemented without using Standard Web Browsers. Recently Magix has announced a flash based desktop and Xplosion, which is based Eclipse technology, is the first product to reintroduce the two way call convention of normal UI-applications. The latter lead to Eclipse rich clients, which can be used without modification as client server applications. Preparing Eclipse Before Eclipse can be used as a web application some modifications have to be made. In typical Web applications the user executes his actions within the context of an assigned session. Important in this context is the consumption of resources for every session. In a standard eclipse environment a user gets exclusively access to the whole eclipse runtime environment. For an application which should serve many users this is not useful. Xplosion uses different from the standard system one per user with a workspace associated with every workbench window. All workbench windows have at this one workbench instance. To implement such a concept some slight changes had to be made. As a result Eclipse becomes a multiuser system. The manufacturer of Xplosion would like to propose this part of the solution as an official Eclipse project. The advantage is, that a user of eclipse can decide to switch to another workspace without time consuming restart of the eclipse platform. User Workbench Workbench 1 : 1 User 1 User 2 User 3 New Eclipse Multiuser Architecture Contact: Ramin Assisi, ramin@assisi-online.com Rich Server Platform (RSP) Page 1 of 7

2 The change of the Eclipse UI to a client server system In the context of this paper, the term client server is used as the decoupling of the UI. To achieve this, one of the API s had to be cut up. Eclipse is based simply on three columns. On the ground you find the Standard Widget Toolkit (SWT), over it the JFace-API and on the top mainly the org.eclipse.workbench.ui and in some cases more specialized API s. To avoid any compatibility problems it was necessary to use the SWT-API as an Interface between client and server. In a few cases this concept could not be used in order to achieve better performance. From the applications perspective which is the perspective of a UI-contributing plugins nothing has really changed. These applications look at the server side API through stubs which has the same calling conventions as the original API. There are some slight differences concerning some insufficiencies of the SWT-API. For instance fields in layout classes can be manipulated directly. The Xplosion-Server assumes therefore, that certain methods like setlayoutdata must be called after those assignments. If applications do not respect this, the result won t be the crash of the application. Rather the layout does not function as planed. Workbench UI JFace Special Streaming Protocol SWT- Remote- Interface SWT-API SWT-Ghost-API New Eclipse Client/Server Architecture The following sections are intended as a proof of concept. Installation The installation of the server comply with an Eclipse RCP application. As a standard port 80 will be used for the communication. Other ports can be configured by a command line parameter. Technically, the Xplosion server consists of standard Eclipse plugins which form an Eclipse workbench. One of these plugins the SWT plugin has been rewritten. Other additional plugins were introduced to fulfill administrative tasks. The client constists of less than 2 Mbyte Java Code. This code is provided with a compiled Java runtime environment and can be download for free from the internet. To simplify the installation, the process has been divided into different steps. In the first step a small 500 KByte bootstrap program will be downloaded. This program take than control over the whole installation and later on over possible update actions. Besides it recognizes, whether a full installation (during first installation resp. after major version changes) or a minor version update should happen. This bootstrap program will also be called every time the client will be started. This will insure that the user does not need to take any action for updates. Start After the installation, the client will be started automatically. Later it is possible to start the client through the start menu. For reasons of load balancing the appropriate server will not be chosen directly. Instead the right IP-address will be provided by a load balancing server. For the user this will be transparent. For him a login dialog will appear, that is already part of the server application. Login dialog after the start of the client Contact: Ramin Assisi, ramin@assisi-online.com Rich Server Platform (RSP) Page 2 of 7

3 Normally all data and configurations will be saved on the server side. As an exception previous input of user data will be saved in the users profile. With Online Demo users can connect to a demo server. User and Password will be provided automatically. If a user wish to be connected to a demo user account he already used before, he can input demouser_1 as user name with the password equal to the user name. Instead 1 any other number can be used. Another concept is the internationalization by translating texts during runtime dynamically instead of using preloaded property resources. This was important to achieve separate languages for every user while having only one workbench instance. Apart from the language, future versions shell support as well the configuration of a certain location. The means, that some functionalities depend on this property. Good examples are bookmarks. Imagine that a user has defined a bookmark first aid and he is vacationing on one of the Philippines islands. He connect to his account and choose the bookmark for first aid. Now he gets the right page with local informations. By factoring in the language, he might even be directed to that local page with its configured language. With download extensions users can download additional client programs which help to increase the productivity. In the actual version the user will be directed to the Open Office download page. The concept of Xplosion implies that documents reside on the server. On the other hand the client considers component technologies like OLE or COM. Such features will be used at least while the server side programs (plugins) have not already reached the sufficient maturity. Xplosion's concept is in this respect an integration between the web and the local environment. Users of the planned portal can open an account directly at this point. The philosophy is the same like in the common -portals or systems like skype where users can migrate from a free of charge service to subsciptions with extended functionalities. Existing users can edit their account from the login dialog. The demo application A demo application should demonstrate the features of the Server in an early stage, when useres havn t yet accounts. After the login a Workbench window becomes visible, which will be associated with the current session. All changes of the UI will be restored after each start. The same is valid for all changes of resources. This will be assured because of the strict segregation of users workspaces. The demo application conforms with a Eclipse IDE with some additional plugins. The Workbench will be started with a predefined perspective named MIO Browser (MIO = Multifunctional Internet Office). Future versions will start programs from a server side task bar where programs means workbench windows with associated perspective. In this respect users can customize their programs by customizing perspectives. One of the purposes of the demo application is, that it should reflect the current situation of the development of Xplosion. For Xplosion it means, that most API s has been implemented. But their are still some bugs. Menu items has to be clicked often twice etc. Part of the concept is, that future versions alow users to communicate directly with the development team. With the new wizard users can create office documents, which will reside on the server. By default internally the OASIS Open Office format will be used. Xplosion wraps these documents always with a special XML-Schema which is called Business Item. It is an abstraction from the special format. For instance in Xplosion a business item can be a text document regardless of the fact that it might be Open Office, MS-Office or any other format. Only if the user wants to send these documents to other systems an export filter will be used. Documents should be transfered with Drag & Drop from the local file system directly to the server application (resp. the navigator view). Automatically all documents will be unified during this process by transforming them to the internal business item format. Office documents can be edited at the moment only by installed OLE-Components (Open Office or MS-Office). An Open Source Plugin is under development, which allows simple paragraph oriented editing. Future plugins shall enable the editing of all office documents with full server side plugins. Contact: Ramin Assisi, ramin@assisi-online.com Rich Server Platform (RSP) Page 3 of 7

4 Open Office OLE component for editing of a server side office document The future server side office components will base on GEF. GEF is suitable for this purpose as all GC paint operations are implemented. In the folder GEF vector graphics the logic and the WISIWYG example of the GEF distribution can be found. The logic example Future versions will be based on Draw2D which will then be part of the client. This will result in a high increase of performance. Contact: Ramin Assisi, ramin@assisi-online.com Rich Server Platform (RSP) Page 4 of 7

5 GEF s WISIWYG example Many solutions, which will be based on Eclipse/Xplosion can benefit from the rich set of existing plugins like those for model driven development. Established technologies like AJAX cannot achieve this. A first statement of the well-known Fraunhofer Institute in Berlin confirmed that. As mentioned before all existing contracts can be used (e.g. register listeners on the server side). The applications response time is also guaranteed by the implementation of Eclipse s multi threading concept (Display.asyncExec). Collaboration With ECF Eclipse a basic approach for collaboration has been introduced. Other existing team provider plugins support the team work. Because all these plugins work in Xplosion, collaboration is possible. Another way is the use of linked resources. In the current version this feature is partially disabled. Especially the user cannot define such linked resources with the dialog extension. In the folder libraries a few images can be found in a predefined linked folder. Future versions shell users allow to define their own linked folders, which will be restricted to protected areas outside of the users workspace. Contact: Ramin Assisi, ramin@assisi-online.com Rich Server Platform (RSP) Page 5 of 7

6 Linked resources Server side browsing Part of Xplosion s concept is the integration of Web-contents and other documents, which will reside on the server side. With the new wizard bookmarks can be created. Opening such a bookmark opens a special multi page editor, where the first page contains the Browser composite of SWT. For s it opens the embedded Internet Explorer (OLE). With that, all UI-elements are part of the server application. Enhancements of the browser UI does not lead to deployments of clients any more. By default user input of internet addresses in the navigation text field or by opening a bookmark result in a method call on the server side. This opens a wide area for new applications. As an example the server can act as a child protection software. A huge collection of URL s can be checked as a positive list which can be maintained by a appropriate child protection organization and which takes into consideration the users (child's) age. Xplosion's browsing facilities have three variants: By default the user input will end in calls of the clients browser component. It communicates directly resp. via a proxy with the internet. As a second method all URL contents will be loaded on the server side. The client browser component acts at this point as a pure rendering engine. This variant is limited by the provided bandwidth. The third variant is not implemented yet. Its concept is similar to the latter one. Additionally the URL contents will be rendered by the browser. The client receives the rendering commands as calls to the SWT-GC class. Altogether all three variants lead to a better control of the content of the internet and their link to the rest of the server based events and this is in line with the requirements of Web 2.0. Contact: Ramin Assisi, ramin@assisi-online.com Rich Server Platform (RSP) Page 6 of 7

7 Server side browsing with Xplosion Applicability All existing SWT-applications including all Eclipse RCP applications can be transformed to client server applications without any adaption. Existing documents can be processed either by COM/OLE components or by adapted SWT applications. Conclusion If you are willing to break through the established web standard by installing a tiny program you will gain an Eclipse client/server system with complete new range of possibilities. The fact is, that Web 2.0 becomes reality in a very short time and all restrictions of the current Web technologies will disappear. Contact: Ramin Assisi, ramin@assisi-online.com Rich Server Platform (RSP) Page 7 of 7