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--- tracing:ex3 [2008/10/06 17:12] – created bdefrain
+++ tracing:ex3 [2021/02/05 13:55] (current) – external edit 127.0.0.1
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-====== Tracing: Specialized logging ======
+[[tracing:intro|Intro]]
+[[tracing:ex1|Ex1]]
+[[tracing:ex2|Ex2]]
+[[tracing:ex3|Ex3]]
+====== Context: Points in groups ======
+===== Specialized tracing =====
+**Task:** Pass the suite ''tests.PointGroupLog''.
+Write an aspect to log whenever a ''Point'' is added to a ''Group''. Note that this requires a dynamic ''instanceof'' test, because in principle any figure element can be added to a group. The log message should simply be:
+    adding Point
+<note tip>
+Use the ''args'' primitive pointcut. Besides exposing context objects, ''this'', ''target'' and ''args'' can also be used to include a dynamic type test in the pointcut.
+</note>
+With your aspect you should be able to pass the tests of suite ''tests.PointGroupLog''.
+===== Extension to invariant checking =====
+**Task:** Pass the suite ''tests.PointGroupInvariant''.
+Add similar advice to ensure that a ''Point'' is never added to more than one ''Group''. If this invariant is violated, the advice should throw an ''IllegalStateException'' that uses the string representation of the first group as its message.
+Take a look a the implementation of the test case to see what is precisely expected.
+<note tip>
+Use an inter-type field declaration to associate a field of type ''Group'' with each ''Point'' object. Check and set this field from the advice.
+</note>
+----
+After you have completed the exercise, remove your aspect from the build path; then return to the [[:start|Overview]].