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diff --git a/docs/dist/doc/README-11.html b/docs/dist/doc/README-11.html index 7417550f7..ff29e5d5b 100644 --- a/docs/dist/doc/README-11.html +++ b/docs/dist/doc/README-11.html @@ -280,6 +280,13 @@ programs from 1.0 to 1.1. clarified. </li> </ul> + <p> Also, it is worth noting that because AspectJ now works on bytecode, + it is somewhat sensitive to how different compilers generate + bytecode, especially when compiling with and without <a + href="#ONE_FOUR_METHOD_SIGNATURES">the -1.4 flag</a>. </p> + + + <!-- ============================== --> <hr> <h2><a name="tools">Support Tools</a></h2> @@ -1461,6 +1468,47 @@ call(* *(int)) && args(i) && !within(A) call(* *(int)) && args(i) && !target(StringBuffer) </PRE> +<h3><a name="ONE_FOUR_METHOD_SIGNATURES">The -1.4 flag and method signatures</a></h3> + +<p> Consider the following aspect +</p> + +<PRE> +public aspect SwingCalls { + + pointcut callingAnySwing(): call(* javax.swing..*+.*(..)); + + before(): callingAnySwing() { + System.out.println("Calling any Swing"); + } +} +</PRE> + +<p> And then consider the two statements +</p> + +<PRE> + JFrame frame = new JFrame(); + frame.setTitle("Title"); +</PRE> + +<p> According to the Java Language Specification version 2, the call +to <code>frame.setTitle("Title")</code> should always produce the +bytecode for a call to <code>javax.swing.JFrame.setTitle</code>. +However, older compilers (and eclipse when run without the +<code>-1.4</code> flag) will generate the bytecode for a call to +<code>java.awt.Frame.setTitle</code> instead since this method is not +overriden by JFrame. The AspectJ weaver depends on the correctly +generated bytecode in order to match patterns like the one you show +correctly. </p> + +<p> This is a good example of why the pattern <code>call(* *(..)) && +target(JFrame)</code> is the recommended style. In general, OO +programmers don't want to care about the static type of an object at a +call site, but only want to know the dynamic instanceof behavior which +is what the target matching will handle. </p> + + <h2><a name="knownLimitations">Known limitations</a></h2> <p>The AspectJ 1.1.0 release contains a small number of known limitations |