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# AspectJ 1.6.2 Readme

The main theme of AspectJ1.6.2 was improved IDE incremental performance and a number of changes have gone in to improve how AspectJ and AJDT communicate - greatly reducing the time taken to perform an incremental compile (more details below). 1.6.2 also includes a number of fixes and enhancements covering areas such as:

- better support for generics and intertype declarations
- better support for annotation style syntax
- improvements to ajdoc
- bringing the AspectJ structure model more in line with the JDT model

Many thanks to all the users that helped diagnose problems, provide testcases and contribute fixes. In particular:

- Dave Whittaker - for generics and intertype declaration testing and testcases
- Jason Naylor, Arturo Salazar - for ajdoc testcases, fixes and design input
- Andrew Eisenberg - for helping shape the AJDT/AspectJ interface and improving incremental

The complete list of issues resolved for AspectJ 1.6.2 (more than 60) can be found with this bugzilla query:

- Bugs resolved

## Incremental compilation (bug 247742, bug 245566, bug 243376)

Two main changes in this area.

- Better communication between AJDT and AspectJ. The interface between the two has been modified so that AJDT can give more input to AspectJ about what needs to be done for an incremental compile, rather than having AspectJ discover it each time.
- Structure model changes. The AspectJ structure model (of types in a project and the weaving amongst them) allows handles to be created for every node, as a lightweight reference to the elements of the model. These handles were similar to those that JDT uses for references to elements of a project but not identical. Many many fixes have gone in to bring the handle formats closer and closer. For example including src folders as elements in the AspectJ model and using the fully correct set of JDT delimiters throughout each handle. This means there is no longer an expensive transformation cost in going from an AspectJ element to its related JDT element and no need for AJDT to maintain a more JDT like version of the AspectJ structure model. The imminent development builds of AJDT will utilise these changes.

What difference does it make?

For every kind of build there are two numbers to take into account. Firstly there is the time spent in the compiler (time spent compiling and weaving), secondly there is the time spent in AJDT (time spent communicating what happened back to the user via the problems view, gutter annotations). Values for these times can be seen by opening the 'AJDT Event Trace View' in eclipse. The changes within AspectJ obviously effect the time spent in the compiler and that is described as 'time spent in AJDE' within the event trace view (AJDE being the compiler wrapper invoked by AJDT).

For a 1000 source file AspectJ project, the times spent in AJDE have changed as follows for a single whitespace change and save operation:

- For a sourcefile unaffected by aspects. Was 1828ms, now 75ms.
- For a sourcefile affected by some advice. Was 1844ms, now 90ms.
- For a sourcefile affected by lots of advice. Was 1937ms, now 188ms.

The AspectJ changes are done to support this, but we are still bedding them down in AJDT. If you want to see numbers like those above you need to install the latest AJDT dev builds for Eclipse 3.4 (an AJDT 1.6.1 dev build from the dev update site: http://download.eclipse.org/tools/ajdt/34/dev/update ) and then after starting Eclipse, select 'Window>Preferences' and in the AspectJ tab select 'Incremental Compiler Optimizations'. Let us know how you get on! When it has had enough testing it will be made the default and then is likely to be back ported to Eclipse 3.3 AJDT.