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- <chapter id="idioms" xreflabel="Idioms">
- <title>Idioms</title>
-
- <sect1 id="idioms-intro">
- <title>Introduction</title>
-
- <para>
- This chapter consists of very short snippets of AspectJ code,
- typically pointcuts, that are particularly evocative or useful.
- This section is a work in progress.
- </para>
-
- <para>
- Here's an example of how to enfore a rule that code in the
- java.sql package can only be used from one particular package in
- your system. This doesn't require any access to code in the
- java.sql package.
- </para>
-
- <programlisting><![CDATA[
- /* Any call to methods or constructors in java.sql */
- pointcut restrictedCall():
- call(* java.sql.*.*(..)) || call(java.sql.*.new(..));
-
- /* Any code in my system not in the sqlAccess package */
- pointcut illegalSource():
- within(com.foo..*) && !within(com.foo.sqlAccess.*);
-
- declare error: restrictedCall() && illegalSource():
- "java.sql package can only be accessed from com.foo.sqlAccess";
- ]]></programlisting>
-
- <para>Any call to an instance of a subtype of AbstractFacade whose class is
- not exactly equal to AbstractFacade:</para>
-
- <programlisting><![CDATA[
- pointcut nonAbstract(AbstractFacade af):
- call(* *(..))
- && target(af)
- && !if(af.getClass() == AbstractFacade.class);
- ]]></programlisting>
-
- <para> If AbstractFacade is an abstract class or an interface, then every
- instance must be of a subtype and you can replace this with: </para>
-
- <programlisting><![CDATA[
- pointcut nonAbstract(AbstractFacade af):
- call(* *(..))
- && target(af);
- ]]></programlisting>
-
- <para> Any call to a method which is defined by a subtype of
- AbstractFacade, but which isn't defined by the type AbstractFacade itself:
- </para>
-
- <programlisting><![CDATA[
- pointcut callToUndefinedMethod():
- call(* AbstractFacade+.*(..))
- && !call(* AbstractFacade.*(..));
- ]]></programlisting>
-
- <para> The execution of a method that is defined in the source code for a
- type that is a subtype of AbstractFacade but not in AbstractFacade itself:
- </para>
-
- <programlisting><![CDATA[
- pointcut executionOfUndefinedMethod():
- execution(* *(..))
- && within(AbstractFacade+)
- && !within(AbstractFacade)
- ]]></programlisting>
-
- </sect1>
- </chapter>
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