from non-functional, development-only aspects to aspects which augment
a deployed program with crosscutting features. </p>
-<p> We have made available a package that includes the tests, the base
-code, JUnit, and a distribution of AspectJ. All it needs is
-information about where Java lives (so set your JAVA_HOME environment
-variable). It assumes that you unzip it in c:\ (on Windows) or in
-your home directory (on Linux): If you put it somewhere else, edit
-setpaths or setpaths.bat, as appropriate. Once all this is done, run
-<code>setpaths.bat</code> or <code>source setpaths</code> to export
-some other needed environment variables. </p>
+<p> Before the tutorial we will make available a package that includes
+the tests, the base code, JUnit, and a distribution of AspectJ. All
+it needs is information about where Java lives (so set your JAVA_HOME
+environment variable). It assumes that you unzip it in c:\ (on
+Windows) or in your home directory (on Linux): If you put it somewhere
+else, edit setpaths or setpaths.bat, as appropriate. Once all this is
+done, run <code>setpaths.bat</code> or <code>source setpaths</code> to
+export some other needed environment variables. </p>
<p> All the files in the program are listed in base.lst, including
test cases and an empty answer aspect,
file and go on to work in a different file, even if you plan to
duplicate some code. </p>
+<h3>Environment</h3>
+
+<p> You may use whatever editor or environment you choose to work
+through these exercises. We provide a simple code-browser that can
+work well as an editor for these short exercises, in addition to
+providing better visualization of how aspects affect the system: </p>
+
+<blockquote><PRE>
+$ ajbrowser base.lst
+</PRE></blockquote>
+
+<p> With the browser you can edit code (including the
+<code>answers/Answer.java</code> file), and after saving hit the build
+button to start an ajc compile. We recommend you start up another
+shell, though, to run the JUnit tests (and don't forget to run the
+<code>setpaths</code> script when you open the new shell): You could
+set up the run button to run a test through the Options menu, but
+we've found this is fairly cumbersome. </p>
+
+
<hr>
-<!-- page break -->
+<!-- ============================== -->
+
+<br style="page-break-after: always" />
<h2>1. Static Invariants</h2>
<h3>a. Catch old tracing</h3>
<p> <strong>Sample Exercise</strong>: The main point of this exercise
-is to make sure your configuration works. We have provided the
-answer to this exercise below, so XXX. You need not go through the
-thought process of fixing this </p>
+is to make sure your configuration works. Type in the answer below
+into your answer file, make sure you get the desired compile-time
+error, remove the offending line, and make sure you pass the JUnit
+test. </p>
<p> <strong>Task:</strong> Signal a warning for calls to
<code>System.out.println</code>.
<blockquote><PRE>
$ ajc -argfile base.lst
-./figures/SlothfulPoint.java:29:9: illegal access to System.out
- System.out.println("Slothful moving");
- ^
-1 errors
+./figures/SlothfulPoint.java:38 illegal access to System.out
+
+1 error
</PRE></blockquote>
<p> Remove the illegal tracing call.
<blockquote><PRE>
$ java tests.Test
....
-Time: 0.076
+Time: 0.03
OK (4 tests)
</PRE></blockquote>
your left and right. If they're stuck somewhere, see if you can help
them. </p>
-<!-- ============================== -->
-
<hr />
-<h2>2. Dynamic invariants</h2>
+<!-- ============================== -->
+<br style="page-break-after: always" />
+<h2>2. Dynamic invariants</h2>
<h3>a. Check a simple precondition</h3>
-<p> <strong>Sample Exercise</strong>: The main point of this exercise
-is to make sure your configuration works. We have provided the
-answer to this exercise below, so XXX. You need not go through the
-thought process of fixing this </p>
-
+<p> <strong>Sample Exercise</strong>: We've provided the answer to
+this exercise below to get you started. </p>
<p> <strong>Task:</strong> Pass <code>tests.Test2a</code>.
</p>
aspect Answer2a {
before(int newValue): set(int Point.*) && args(newValue) {
- if (newValue < 0) {
+ if (newValue < 0) {
throw new IllegalArgumentException("too small");
}
}
call.
</p>
-XXX RENUMBER LATER
-
<h3>d. Assure input</h3>
<p> <strong>Task: </strong> Pass <code>tests.Test2g</code>.
<p> At this point, check the people to your left and right. If
they're stuck somewhere, see if you can help them. </p>
-<!-- ============================== -->
-
<hr />
-<!-- page break -->
-
-<h2>3. Logging</h2>
-
-<h3>d. Check a simple postcondition</h3>
-
-<p> One of the simplest postconditions to check is that a setter
-actually sets its value. Write an aspect that throws a
-<code>java.lang.RuntimeException</code> if, after calling
-<code>setX()</code> on <code>SlothfulPoint</code> objects,
-<code>getX()</code> doesn't return the new value. </p>
-<p> You'll want to use an <code>args</code> pointcut to expose the
-argument to <code>setX()</code> and a <code>target</code> pointcut to
-expose the <code>SlothfulPoint</code> object itself (so you can later
-call <code>getX()</code> on it).
-</p>
-
-<p> An interesting question to think about for discussion is whether
-this postcondition should apply when getX() throws an exception, or
-when it returns normally, or both? </p>
-
-<p> With this aspect in place, your code should pass
-<code>tests.Test2d</code>.
-</p>
-
-
-<h3>e. Check invariant</h3>
-
-<p> There is a method on the <code>Box</code> class, <code>void
-checkBoxness()</code>, that checks whether the four points making up a
-box are correctly positioned relative to each other (i.e., they form a
-rectangle). Write an aspect that will make sure that after every time
-the <code>void move(int, int)</code> method on <code>Box</code> is
-called, that you also call <code>Box.checkBoxness()</code> to ensure
-that the <code>move</code> didn't break this invariant. </p>
-
-<p> With this aspect in place, your code should pass
-<code>tests.Test2e</code>.
-</p>
-
-<h3>f. Refine your invariant</h3>
-
-<p> <code>move</code> is not the only interesting method on
-<code>Box</code>. It may be that a box gets malformed between calls
-to <code>move</code>. So instead of checking boxness only
-after the <code>move</code> method of <code>Box</code>, check
-after the call to every one of <code>Box</code>'s public methods.
-</p>
-
-<p> When testing this aspect, you may find yourself facing a
-<code>StackOverflowException</code>. If so, carefully look at your
-pointcuts. Needless to say, there should not be an infinite loop in
-your program. You might want to look at using a <code>within</code>
-pointcut for a filter. </p>
-
-<p> (You might even find that this test case aborts with no message,
-i.e.,
-</p>
-
-<blockquote><pre>
-$ java tests.test2f
-.
-$
-</pre></blockquote>
-
-<p> this is a bug in Sun's JVM where a particular stack overflow
-causes the VM to abort.)
-</p>
-
-<p> Make sure to pass the JUnit test <code>tests.Test2f</code>
-before continuing. </p>
+<!-- ============================== -->
-==================================================
+<br style="page-break-after: always" />
+<h2>3. Tracing</h2>
<p> The crosscutting feature you will be adding in part (4) will be
support for caching the bound objects of <code>Group</code> figure
<h3>a. Simple logging</h3>
-<p> <strong>Problem:</strong> Pass <code>tests.Test3a</code>.</p>
+<p> <strong>Task:</strong> Pass <code>tests.Test3a</code>.</p>
<p> <strong>Tools:</strong> <code>Log.log(String)</code>,
<code>thisJoinPoint.toString()</code>, <code>execution</code>,
<h3>b. Simple logging</h3>
-<p> <strong>Problem:</strong> Pass <code>tests.Test3b</code>.</p>
+<p> <strong>Task:</strong> Pass <code>tests.Test3b</code>.</p>
<p> <strong>Tools:</strong> <code>target</code>
</p>
<h3>c. More specialized logging</h3>
-<p> <strong>Problem:</strong> Pass <code>tests.Test3c</code>.</p>
+<p> <strong>Task:</strong> Pass <code>tests.Test3c</code>.</p>
<p> <strong>Tools:</strong>
</p>
<h3>d. Logging extended to checking an invariant</h3>
-<p> <strong>Problem:</strong> Pass <code>tests.Test3d</code>.</p>
+<p> <strong>Task:</strong> Pass <code>tests.Test3d</code>.</p>
<p> <strong>Tools:</strong> <code>inter-type field declaration</code>
</p>
<h3>e. Better error messages for 3d</h3>
-<p> <strong>Problem:</strong> Pass <code>tests.Test3e</code>.</p>
+<p> <strong>Task:</strong> Pass <code>tests.Test3e</code>.</p>
<p> <strong>Tools:</strong>
</p>
<p> At this point, check the people to your left and right. If
they're stuck somewhere, see if you can help them. </p>
+<hr />
<!-- ============================== -->
-<hr />
-
-<!-- page break -->
-<h3>4. Caching</h3>
+<br style="page-break-after: always" />
+<h2>4. Caching</h2>
<p> Computation of the bounding box of <code>Group</code> objects
needs to deal with all aggregate parts of the group, and this
<h3>a. Make a constant override</h3>
-<p> <strong>Problem:</strong> Pass <code>tests.Test4a</code>.</p>
+<p> <strong>Task:</strong> Pass <code>tests.Test4a</code>.</p>
<p> <strong>Tools:</strong> <code>around</code>,
<code>FigureElement.MAX_BOUNDS</code>
<h3>b. Make a constant cache</h3>
-<p> <strong>Problem:</strong> Pass <code>tests.Test4b</code>.
+<p> <strong>Task:</strong> Pass <code>tests.Test4b</code>.
</p>
<p> <strong>Tools:</strong> <code>private Rectangle Group.mumble;</code>
<h3>c. Invalidate, part 1</h3>
-<p> <strong>Problem:</strong> Pass <code>tests.Test4c</code>.
+<p> <strong>Task:</strong> Pass <code>tests.Test4c</code>.
</p>
<p> <strong>Tools:</strong> <code>before</code>
<h3>d. Invalidate, part 2</h3>
-<p> <strong>Problem:</strong> Pass <code>tests.Test4d</code>.</p>
+<p> <strong>Task:</strong> Pass <code>tests.Test4d</code>.</p>
<p> <strong>Tools:</strong> <code>your solution to 3c</code></p>
<h3>e. Invalidate, part 3</h3>
-<p> <strong>Problem:</strong> Pass <code>tests.Test4e</code>.</p>
+<p> <strong>Task:</strong> Pass <code>tests.Test4e</code>.</p>
<p> <strong>Tools:</strong> <em>You're on you're own</em></p>
projects / aspectj.git / commitdiff