123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204 |
- <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
- <html> <head>
- <title>AspectJ 1.6.4 Readme</title>
- <style type="text/css">
- <!--
- P { margin-left: 20px; }
- PRE { margin-left: 20px; }
- LI { margin-left: 20px; }
- H4 { margin-left: 20px; }
- H3 { margin-left: 10px; }
- -->
- </style>
- </head>
-
- <body>
- <div align="right"><small>
- © Copyright 2009 Contributors.
- All rights reserved.
- </small></div>
-
- <h1>AspectJ 1.6.4 Readme</h1>
-
- <ul>
- <li><a href="#compilation">Compilation times</a></li>
- <li><a href="#language">Language enhancements</a></li>
- <li><a href="#bugsfixed">Bugs fixed</a></li>
- <li><a href="#whatsnext">What's next?</a></li>
- </ul>
- <hr>
- <a name="compilation"/>
- <H4>Compilation times</h4>
- <p>In AspectJ 1.6.4 the goal was to improve the IDE experience, through a combination of improved compilation speed (both full
- builds and incremental builds), improved support for multiple-project configurations, and improved feedback in the editor. The
- following sections go into details on each of those topics.</p>
-
- <p><B>Full Compilation</b></p>
- <p>As an example project, all the measurements here are based on the modified JDT compiler that AspectJ uses internally. It is
- 1100 source files and includes aspects that affect around 850 join points. Here are the full build times in AJDT:
- </p>
- <p>AJDT 1.6.3 (uses AspectJ 1.6.3)</p>
- <code><pre>
- 21352ms
- 21597ms
- 21502ms
- </pre></code>
-
- <p>AJDT 1.6.5dev builds (use AspectJ 1.6.4)</p>
- <code><pre>
- 19811ms
- 19802ms
- 19504ms
- </pre></code>
- <p>
- About 1.5-2 seconds faster for this example.
- </p>
- <p><b>Incremental Compilation and multi-project scenarios</b></p>
- <p>In most common project configurations there are multiple eclipse projects in some kind of dependency hierarchy. Depending on
- what changes in a top level project, those downstream may need to be rebuilt. The analysis around this area has greatly improved
- in AspectJ 1.6.4, and this has resulted in much reduced incremental build times. The example timed here is around 20 AspectJ
- projects in a hierarchy, and a change is made to a source file in the top level project and build times are observed for the
- downstream projects.</p>
- <p>The timings reported here are accessible to anyone with AJDT installed - just open the 'AJDT Event Trace View' and it will
- report ongoing information about what the compiler/weaver and AJDT are up to. Be aware that data is only recorded in this view
- if it is open - so for optimal performance it should be shutdown, but it is useful for debugging scenarios or collecting
- basic benchmark numbers. Within the event trace view output, the time recorded for 'time spent in AJDE' represents the time
- spent in the compiler: analysing what has changed on the classpath, building code, weaving code.
- </p>
- <p>Initially this is using AJDT 1.6.2 (which embeds AspectJ 1.6.3):</p>
- <p>
- <code><pre>
- Type of change: adding a new method to a type
- Project build times (first one is the compile of our change, the rest are for downstream projects):
- 462ms, 4ms, 145ms, 8ms, 9ms, 287ms, 471ms, 222ms, 1028ms, 143ms, 505ms, 199ms, 261ms, 1224ms,
- 321ms, 704ms, 75ms, 233ms, 257ms
- Summary: Total time spent in the compiler for that change: <b>6558ms</b>
- ---
- Type of change: whitespace change (adding just a harmless space character)
- Project build times (first one is the compile of our change, the rest are for downstream projects):
- 229ms, 5ms, 10ms, 9ms, 10ms, 79ms, 43ms, 62ms, 80ms, 37ms, 64ms, 32ms, 79ms,
- 154ms, 94ms, 189ms, 72ms, 144ms, 205ms
- Summary: Total time spent in the compiler for that change: <b>1597ms</b>
- </pre></code>
- </p>
- <p>Now with AspectJ 1.6.5 dev builds (which embed AspectJ 1.6.4):</p>
- <p>
- <code><pre>
- Type of change: adding a new method to a type
- Project build times (first one is the compile of our change, the rest are for downstream projects):
- 288ms, 3ms, 143ms, 2ms, 2ms, 162ms, 244ms, 89ms, 489ms, 113ms, 277ms, 108ms, 143ms, 626ms,
- 135ms, 260ms, 2ms, 96ms, 6ms
- Summary: Total time spent in the compiler for that change: <b>3188ms</b> down from 6558ms
-
- Type of change: whitespace change (adding just a harmless space character)
- Project build times (first one is the compile of our change, the rest are for downstream projects):
- 101ms, 1ms, 1ms, 1ms, 0ms, 1ms, 1ms, 1ms, 1ms, 1ms, 0ms, 1ms, 1ms, 2ms, 0ms, 1ms, 0ms, 2ms, 2ms
- Summary: Total time spent in the compiler for that change: <b>118ms</b> (down from 1597ms)
- </pre></code>
- </p>
- <p>
- Improvements all round, and almost instant builds now for whitespace changes, even in large
- project setups.
- </p>
- <p>In addition the compilation times are also improved in situations where AspectJ projects depend upon Java projects and
- where aspectpath is used. AJDT 1.6.5 dev builds also include some changes that really speed up builds.
- </p>
- <h4>Better editor feedback</h4>
- <p>Under <a href="https://bugs.eclipse.org/bugs/show_bug.cgi?id=246393">bug 246393</a> the problem has been addressed where
- sometimes spurious errors would appear throughout the editor for a file in AJDT when just one single simple syntax errors exists. More
- detail on this problem can be found
- <a href="http://andrewclement.blogspot.com/2009/02/aspectj-fixing-reverse-cascade-errors.html">here</a>.
- </p>
- <hr>
- <a name="language"/>
- <H4>Language Enhancements</h4>
- <p><b>Optimizing support for maintaining per join point state</b></p>
- <p>The traditional way to maintain state on a per join point basis involves using the JoinPoint.StaticPart as a key
- into a map:
- <code><pre>
- aspect X pertypewithin(*) {
- Map<JoinPoint.StaticPart,Timer> timerMap = ...
-
- Object around(): execution(public * *(..)) {
- Timer timerToUse = timerMap.get(thisJoinPointStaticPart);
- timerToUse.start();
- Object o = proceed();
- timerToUse.stop();
- return o;
- }
- }
- </pre></code>
- <p>These map lookups are slow. In AspectJ 1.6.4 there is a new getId() method on the JoinPoint.StaticPart object.
- The ids for all affected join points within a target type are unique (and start from 0) - they are ideal for
- array lookups. So using this the above aspect can be rewritten:
- </p>
-
- <code><pre>
- aspect X pertypewithin(*) {
- Timer[] timerArray = ...
-
- Object around(): execution(public * *(..)) {
- Timer timerToUse = timerArray[thisJoinPointStaticPart.getId()];
- timerToUse.start();
- Object o = proceed();
- timerToUse.stop();
- return o;
- }
- }
- </pre></code>
- <p>much faster. Just be aware that the ids are only unique within an affected target type - hence the use of pertypewithin
- in this example to ensure there is an aspect instance (and so a different array) for each advised type.</p>
- <p>See related <a href="https://bugs.eclipse.org/bugs/show_bug.cgi?id=89009">bug 89009</a> for the full discussion</p>
-
- <h4>@DeclareMixin</h4>
- <p>The annotation style declare parents support (@DeclareParents) has been (rightly) criticized because it really does not offer
- an equivalent to what is possible with code style declare parents, it really offers a mixin strategy. It also has limitations
- such as the delegate instance used to satisfy any method invocations on an affected target cannot access the object instance for
- which it is acting as a delegate. To address these concerns a proper mixin notation has been introduced that makes it more clear
- that a mixin strategy is being employed and it addresses the problem of the mixin delegate accessing the affected target instance.
- </p>
- <p>
- The @DeclareMixin annotation is attached to a factory method which returns instances of the delegate. Here is a basic example:
- </p>
- <code><pre>
- // The factory method that can build the delegate instance is annotated with @DeclareMixin.
- // The annotation value defines the type pattern for targets of the mixin.
- // The parameter is the object for which a delegate is being constructed.
- // The interface that will be mixed in is the return value of the factory method.
- @DeclareMixin("org.xyz..*")
- public static SomeInterface createDelegate(Object instance) {
- return new SomeImplementation(instance);
- }
- </pre></code>
- <p>More examples are <a href="http://www.eclipse.org/aspectj/doc/released/adk15notebook/ataspectj-itds.html">here in the online
- documentation</a>.</p>
- <p>Going forward attempts will be made to try and make @DeclareParents behave more like code style - if this cannot
- be done it is likely to be deprecated.</p>
- <hr>
- <a name="bugsfixed"/>
- <h4>Bugs fixed</h4>
- <p>The complete list of issues resolved for AspectJ 1.6.4 (more than 70) can be found with
- this bugzilla query:
- <ul>
- <li><a href="https://bugs.eclipse.org/bugs/buglist.cgi?query_format=advanced&short_desc_type=allwordssubstr&short_desc=&product=AspectJ&target_milestone=1.6.4&long_desc_type=allwordssubstr&long_desc=&bug_file_loc_type=allwordssubstr&bug_file_loc=&status_whiteboard_type=allwordssubstr&status_whiteboard=&keywords_type=allwords&keywords=&bug_status=RESOLVED&bug_status=VERIFIED&bug_status=CLOSED&emailtype1=substring&email1=&emailtype2=substring&email2=&bugidtype=include&bug_id=&votes=&chfieldfrom=&chfieldto=Now&chfieldvalue=&cmdtype=doit&order=Reuse+same+sort+as+last+time&field0-0-0=noop&type0-0-0=noop&value0-0-0=">Bugs resolved</a>
- </ul>
- <hr>
- <a name="whatsnext"/>
- <h4>What's next?</h4>
- <p><b>More incremental build enhancements</b></p>
- <p>A number of situations still exist where incremental compile speeds still needs optimizing, particular when capabilities
- like aspectpath or inpath are used.</p>
- <p><b>Build state persistence</b></p>
- <p>Between restarts of Eclipse the state of each project is not recorded - hence full builds are required upon restart. The
- state (and associated relationship model) should be persisted between restarts, but both of these need a review first to ensure
- they are not larger than they need to be.
- </p>
- <p><b>Memory consumption</b</p>
- <p>Both for source compilation and load-time weaving scenarios. The size of the model in the IDE needs reviewing, and also the
- type map within the weaver. Although the type map uses Weak/Soft references to try and better control how it uses memory, the JVM
- policies for managing these references vary wildly and so some work needs to be done to allow for these differences.
- <hr>
-
- <!-- ============================== -->
- </body>
- </html>
|