Last updated on May 17, 2003.
The beginnings of an FAQ for AJDT...
The AspectJ Development Tools project (AJDT) is a set of plugins for Eclipse that provide support for aspect-oriented software development using AspectJ within the Eclipse IDE.
AJDT is an open-source project hosted on eclipse.org, current contributors are listed on the website. Anyone can get involved, see "How can I contribute?"
The latest releases are available from the AJDT download page.
AJDT provides Eclipse IDE integration for AspectJ, and includes the Ajde libraries from the AspectJ project as part of its packaging. Development of the AspectJ compiler and AJDE takes place under the AspectJ project.
AJDT is supported through the eclipse.technology.ajdt newsgroup. A web interface is also available.
First check the bug database to see if you've hit a known problem. There's also a view built into AJDT (Window->Show View->Other...->AspectJ->AJDT Event Trace) that displays a lot of diagnostic information about the execution of the plugin (for example, it will show you the exact classpaths being used for compilation). If it appears to be a genuinely new bug, please submit a bug report on AJDT using bugzilla following the bug reporting guidelines.
Informal requests can be posted to the newsgroup or mailing list. Formal requests can be made by raising an AJDT enhancement request on Bugzilla.
AJDT has a developers mailing list, ajdt-dev@dev.eclipse.org, with archives and subscription information available online. Questions regarding the use of AspectJ the language are best directed to the AspectJ users mailing list.
The most common cause of this problem is opening Java files (files with the .java extension) using the JDT's Java Editor. AJDT provides an extension to the Java Editor, the AspectJ Editor, that recognizes AspectJ language structure and provides an outline view that displays crosscutting structure information. To configure Eclipse so that Java files are opened with the AspectJ editor, select "preferences" from the Window menu. Expand the workbench preferences and click on "File Associations." Select file type "*.java," then select the AspectJ Editor and click the "Default" button.
AJDT doesn't yet provide an eager parser for AspectJ. The early problem indication support is therefore expecting to see a regular Java program, and so treats AspectJ keywords as errors. The squiggles can be turned off by opening preferences from the Window menu: Expand the Java preferences and click on "Editor." In the "Problem Indication" tab, uncheck the option "Show problems before compiling."
AJDT doesn't yet provide an eager parser for AspectJ, so the understanding of the editor buffer contents needed to update the outline view is only after a compilation. The process of compiling creates a structure model (including the crosscutting information) that the outline view then renders.
The class files generated by AspectJ have the property that a single class file may have been generated from multiple source files (for example, the source file for a domain class and the source file for an aspect that advises it). This complicates the line number table present in the class file, since we need to record not only which line number is associated with a set of bytecodes, but which file as well. Fortunately there's a JSR, JSR 45, which specifies how to do this in a standard way so that debuggers can interpret the information correctly. With a compiler that generates JSR 45 compliant meta-information in class files, a JSR 45 compliant JVM, and a JSR 45 compliant debugger, you will be able to seamlessly step across source files, set breakpoints etc..
JSR 45 didn't quite make it into the list of approved JSRs for JDK 1.4, but Sun's JDK provides an implementation of it anyway! Eclipse has JSR 45 support as a plan item for the 2.2 release. AspectJ 1.0.6 generates JSR 45 compliant class files, but the new 1.1 compiler doesn't (yet). When both Eclipse and AspectJ 1.1 support JSR 45 then full debug capability will be available.
In the meantime, you can work with AspectJ programs in the debugger with the following limitations:
The AJDT support for incremental compilation mode is not complete. In particular the outline view is only updated for the file currently being edited, to refresh the structure model select "Project-rebuild all." Incremental support in AspectJ itself is also one of the newest and therefore least tested features on real world projects. AJDT therefore turns off incremental compilation by default, and builds are done on demand using the AJDT build button. You can turn automatic building back on by selecting preferences from the Window menu, and in the AspectJ page deselect "Suppress automatic building for AspectJ projects." These automatic builds will be *full* builds unless you also select the incremental compilation option on the properties page of the project in question.
The visualiser consists of two views, the Aspect Visualiser and the Aspect Menu, both of which need to be open: Select "Window" , "Show View" , "Other... AspectJ" from the taskbar, then select "Aspect Visualiser" and "Aspect Menu " and click OK.
To visualise an AspectJ project, click on the AspectJ Project in the Package Explorer (for the Visualiser to work you must have at least one aspect active in the project i.e. included in the current build list). The aspects defined in that project should appear in the Menu. The Visualiser shows all the classes in your project with bar length proportional to number of lines of code. Dark bars represent classes not affected by an aspect. Coloured lines on the white bars represent lines of code affected by the Aspect in the Menu which has the corresponding colour. It is also possible to click on individual classes or packages in the package explorer to see their individual representations.
The Visualiser starts in class mode by default. Click on the package button to choose package mode. Here each bar represents a package in your project and length is proportional to total number of lines. Package view was designed as an overview, particularly for large projects. Click on the class button to return to class mode.
In either package or class mode, clicking on the limit button restricts the view to affected bars only. Clicking again leaves limit mode.
Subselect mode can be used to view selected bars by themselves. Click on the title buttons of the required bars. Then click on the subselect button to view the selected bars. Click on the subselect button again to leave subselect mode. You may need to click on the project again in the package explorer.
To open the source file of a represented class, go into class mode and double click on the corresponding bar. To open a source file at a line affected by an aspect, go into class mode and double click on the corresponding coloured line.
The JoinPoint probe was an experimental function that made a brief appearance in AJDT 0.5.2 and 0.6.0beta. We have temporarily removed it from AJDT whilst we work out the correct user-interaction model and port the Swing UI to SWT.
Your contributions to the AJDT project are strongly welcomed! You can create a patch that fixes a bug or provides an enhancement and submit it to the AJDT developers either as an attachment to a bug in Bugzilla, or as an attachment to a post to the newsgroup or developer mailing list. You can also contribute sample code showing interesting uses of AspectJ, by adding entries to the example plugin. All contributions must be made available under the terms of the Eclipse website see the Eclipse contribution and participation FAQ. Sorry, but for legal reasons we are unable to accept patches emailed directly to developers, and will normally ask you to resubmit these either via Bugzilla or the mailing list.
AJDT development is run as a meritocracy, developers who have a track record of submitting good patches can become committers on the project.
The org.eclipse.ajdt.examples plugin contains various sample projects which are made available under the Examples category of the New wizard, from where they can be imported into your workspace as AspectJ projects. It is easy to add new samples to this plugin, as follows:
AJDT source is held in the Eclipse CVS repository under /home/technology, see the root of the AJDT source tree online. AJDT is organized in subdirectories of org.eclipse.ajdt as follows:
org.eclipse.ajdt | |--> plugins |--> org.eclipse.ajdt (source of the AJDT UI plugin) |--> org.aspectj.ajde (the AJDE plugin provided by the AspectJ project) |--> org.eclipse.aspectj (the "feature" plugin that provides the AspectJ feature) |--> features |-->org.eclipse.aspectj (the AspectJ feature) |--> update (files used to create the AspectJ update site) |--> binaries (archives of selected binaries made available for download)
Start with a clean workspace under Eclipse 2.0.2 or 2.1:
:pserver:anonymous@dev.eclipse.org:/home/technology
Each of the projects you just created also contains an Ant build file, "build.xml." The default target builds a packaged version of the project in question. Use the build.xml file in the "update" project to invoke a master build that builds an entire update site structure in its "dist" directory.
See the task list on our project home page.