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# AspectJ 1.6.9 Readme

## Features of 1.6.9 milestone 1

### Message inserts for declare warning/error messages

It is now possible to use joinpoint context in the messages attached to declare warning and declare error constructs. Some examples:

`

    declare warning: execution(* A.m(..)): "joinpoint is {joinpoint}";
    declare warning: execution(* A.m(..)): "joinpoint kind is '{joinpoint.kind}'";
    declare warning: get(int *) && within(A): "joinpoint signature is {joinpoint.signature}";
    declare warning: execution(* A.m(..)): "joinpoint declaring type is {joinpoint.signature.declaringType}";
    declare warning: execution(* A.m(..)): "signature name for method is {joinpoint.signature.name}";
    declare warning: execution(* A.m(..)): "joinpoint location is {joinpoint.sourcelocation.sourcefile}:{joinpoint.sourcelocation.line}";
    declare warning: execution(* A.m(..)): "joinpoint line is '{joinpoint.sourcelocation.line}'";

    declare warning: get(int *): "warning is from aspect {advice.aspecttype}";
    declare warning: execution(* A.m(..)): "warning sourcelocation is {advice.sourcelocation.sourcefile}:{advice.sourcelocation.line}";

`

The syntax is to enclose the relevant key within curly brackets within the message. Please raise an enhancement request if you need other keys - the set supported so far are all those shown in the example above.

### declare warning/error for type patterns

It is now possible to use a type pattern with declare warning and declare error. For example:

`

    declare warning: I+ && !hasfield(int i): "Implementations of I are expected to have a int field called i";

`

### Type category type patterns

This is the ability to narrow the types of interest so that interfaces can be ignored, or inner types, or classes or aspects. There is now a new is() construct that enables this:

`

    execution(* (!is(InnerType)).m(..)) {}
    !within(* && is(InnerType)) {}

`

Options for use in is() are: ClassType, AspectType, InterfaceType, InnerType, AnonymousType, EnumType, AnonymousType.

Note: It is important to understand that "!within(is(InnerType))" and "within(!is(InnerType))" are not the same. The latter one is unlikely to be what you want to use. For example here: ``

    class Boo {
      void foo() {}
      class Bar {
        void foo() {}
      }
    }

Bar.foo() will match within(!is(InnerType)) because within considers all surrounding types (so although Bar doesn't match the pattern, the surrounding Boo will match it). Bar.foo() will not match !within(is(InnerType)) because Bar will match the pattern and then the result of that match will be negated.

### Intertype fields preserve visibility and name

Some users always expect this:

`

    class C {
    }

    aspect X {
      private int C.someField;
    }

`

To cause a private field called 'someField' to be added to C. This is conceptually what happens during compilation but if any user then later attempts to access someField via reflection or runs a javap against the class file, they will see that isn't what happens in practice. A public member is added with a mangled name. For code attempting to access someField built with ajc, the visibility of the declaration will, of course, be respected. But for frameworks accessing the code later (typically through reflection), it can cause confusion. With AspectJ 1.6.9 the name and visibility are now preserved. Compile time semantics remain the same, it is only the weaving process that has changed to produce slightly different output.

Here is the output of javap when that is built with 1.6.8:

`

    class C extends java.lang.Object{
        public int ajc$interField$X$someField;
        C();
    }

`

Here is the output of javap when that is built with 1.6.9:

`

    class C extends java.lang.Object{
        private int someField;
        C();
        public static int ajc$get$someField(C);
        public static void ajc$set$someField(C, int);
    }

`

The name 'someField' is preserved. The visibility is also preserved but because of that we also need to generate some accessors to get at the field.

### AspectJ snapshots in a maven repo

To ease how AspectJ development builds can be consumed, they are now placed into a maven repo. When a new version of AspectJ is put into AJDT it is also put into the maven.springframework.org repo. The maven compatible repo is `maven.springframework.org/snapshot/org/aspectj` - and if you browse to it you will see it currently contains 1.6.9 dev builds under the name 1.6.9.BUILD-SNAPSHOT. The repo is added with this magic:

`

    <repository>
        <id>maven.springframework.org</id>
        <name>SpringSource snapshots</name>
        <url>http://maven.springframework.org/snapshot</url>
    </repository>

`

and then the version to depend upon is: 1.6.9.BUILD-SNAPSHOT

####