Tool designed to check whether the advices affecting the execution of a method comply with the Advice Substitution Principle. Developed as a Proof of Concept for a Master Thesis done in the University of Antwerp. Instructions on how to use the tool as well as a detailed explanation of the checking tasks performed are availble at the Thesis report.

The ASP-checker uses the behavioural subtyle checker as a basis and provides similar functionality for AspectJ. It is available as an AJDT plugin.

##Purpose

As it happens due to polymorphism in object oriented inheritance, the execution of aspects can carry unexpected consequences. If an aspect advising a method does not behave as a behavioural subtype it can cause undesired effects that are unknown for the code that executes the method.

This checker retrieves all the advices affecting a method and checks whether they comply with the ASP rules. The contracts that can be specified are:

• Requires
• Ensures
• Invariant

There is one additional contract that can be used in the cases in which compliance with the ASP cannot be achieved, such as security or authentication, where a consequence of the advice could be not executing the originally intended functionality. This is achieved by using the advisedBy contract. This contract attaches to the method and marks these changes in its behaviour.

##Usage

The 3 contracts can be attached as Java annotations to both methods an advices. advisedBy clauses can be used with methods, while a name annotation must be used with the advices in order to give them a name and be included in advisedBy clauses.

Contracts can be specified in a subset of Java that covers the basic expressions. For more information about what it is supported, refer to the report. A simple example of a par of advice and method could be the following:

@requires("a.length > 10")
@advisedBy("bar")
void foo(String a){...}

@ensures("str.isEmpty()")
@name("bar")
void before(String str): call( void *.foo (String)) && args(str) {...}

##Install Information regarding installation can be found in the INSTALL.md file.