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| -rw-r--r-- | docs/teaching/exercises/index.html | 177 |
1 files changed, 61 insertions, 116 deletions
diff --git a/docs/teaching/exercises/index.html b/docs/teaching/exercises/index.html index 500915e99..f44ac7806 100644 --- a/docs/teaching/exercises/index.html +++ b/docs/teaching/exercises/index.html @@ -13,14 +13,14 @@ cases. They progress, as most users do in their adoption of AspectJ, 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, @@ -72,16 +72,39 @@ you go from one exercise to the next, make sure to save your work in a 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>. @@ -100,10 +123,9 @@ trace in <code>SlothfulPoint</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. @@ -116,7 +138,7 @@ all exercises) before continuing. </p> <blockquote><PRE> $ java tests.Test .... -Time: 0.076 +Time: 0.03 OK (4 tests) </PRE></blockquote> @@ -215,20 +237,17 @@ the convention. Make sure your program still passes the JUnit test 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> @@ -283,7 +302,7 @@ import figures.*; aspect Answer2a { before(int newValue): set(int Point.*) && args(newValue) { - if (newValue < 0) { + if (newValue < 0) { throw new IllegalArgumentException("too small"); } } @@ -322,8 +341,6 @@ an attempt is made to call <code>Group.add()</code> on a call. </p> -XXX RENUMBER LATER - <h3>d. Assure input</h3> <p> <strong>Task: </strong> Pass <code>tests.Test2g</code>. @@ -380,83 +397,12 @@ throw an <code>IllegalStateException</code> if it is violated. </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 /> -<!-- 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 @@ -465,7 +411,7 @@ it's useful to explore the system with some tracing aspects. </p> <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>, @@ -479,7 +425,7 @@ and call <code>Log.log(String)</code></p> <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> @@ -487,7 +433,7 @@ and call <code>Log.log(String)</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> @@ -520,7 +466,7 @@ based on the type of a parameter to a method call. </em> </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> @@ -530,7 +476,7 @@ based on the type of a parameter to a method call. </em> </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> @@ -581,13 +527,12 @@ previous exercises, you'll be most of the way there. </em> </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 @@ -602,7 +547,7 @@ handle those points contained in Lines and Boxes only if time permits. <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> @@ -623,7 +568,7 @@ around advice intercepting the method. <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> @@ -642,7 +587,7 @@ state for every <code>Group</code> object.</em> </p> <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> @@ -656,7 +601,7 @@ Change your aspect so that it invalidates the cache whenever the <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> @@ -670,7 +615,7 @@ where there you cared about method calls. </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> |