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--- caching:ex2 [2007/02/26 18:32] – created bdefrain
+++ caching:ex2 [2021/02/05 13:51] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
-====== Caching: Constant cache ======
+[[caching:intro|Intro]]
+[[caching:ex1|Ex1]]
+[[caching:ex2|Ex2]]
+[[caching:ex3|Ex3]]
+[[caching:ex4|Ex4]]====== Caching: Constant cache ======
+===== Using inter-type declarations =====
 **Task:** Pass ''tests.BoundsConstantCache''.
@@ Line 10: / Line 16: @@
 A correct implementation should pass the tests of suite ''tests.BoundsConstantCache''.
+When done, remove the aspect from your build path before continuing with the next part.
+===== Using several aspect instances =====
+Imagine that a ''Group'' is [[wp>Serialization|serialized]] to some storage medium. If we use inter-type declarations to introduce a new field for the ''Group'' class, then this field will be included in the serialized data of a ''Group'' (so the schema changes). This is undesirable.
+To avoid this, write a new version of the above aspect that does not change the fields of the ''Group'' class.
+<note tip>
+Store the field in the aspect itself and use the ''perthis'' instantiation strategy to have one aspect aspect instance for each advised ''Group'' object.
+</note>
+A correct implementation should also pass the tests of suite ''tests.BoundsConstantCache''.
+When done, remove the aspect from your build path before continuing with the next part.
+===== Reusable caching aspect =====
+A //reusable// caching aspect seems very useful. Create a generic caching aspect from your previous result by extracting at least:
+  * The type of the cache value: i.e. ''Rectangle'' should not be hardcoded, use a type variable instead
+  * The operation being cached: i.e. ''Group.getBounds()'' should not be hardcoded, make this pointcut abstract
+Then reimplement your solution using this generic caching aspect. The new implementation should still pass the tests of suite ''tests.BoundsConstantCache''.
 ----
-Keep your aspect active and continue with [[caching:ex3|Exercise 3]].
+Keep the last of your caching aspects active and continue with [[caching:ex3|Exercise 3]].