Hyper/J and Concern Manipulation Environment

The need for AOSD tools and development environment AOSD requires a variety of tools Life cycle – support all stages of artifact development Task directed – constraint enforcement, performance, feature addition etc. Paradigm specific – concern composition, aspect attachment

Problems Lack of framework for initial tool development Integration is difficult – most tools are implemented from scratch Customization is nearly impossible

Possiblesolution Possible solution Abstraction of basic concepts of concern oriented modeling Reusable components for tool developers Layered architecture

ConcernManipulation Environment Concern Manipulation Environment Developed by IBM research labs Presented at AOSD 2004 Supports next generation of HyperJ Extensible, reusable, open, customizable base for tool developers Some ready for use tools and integration with Eclipse Open source

CMEArchitecture CME Architecture 4 main layers – tools, components, framework and engines Communication between layers are through API and interfaces defined by CME Partial implementation of the most important modules of each layer is provided by CME Each layer is open for extension by tool developers

ToolsLayer Tools Layer End user tools + GUI Customized for tasks, lifecycle stages, artifacts, AOSD paradigms, environments Intended for extension by tool developers more than other layers

Toolslayer – existingitems Tools layer – existing items Concern explorer for Eclipse – creation and manipulation of concern models and composition for Java Package explorer style view Visualize code affected by concern Query interface Concern modeler – express the concerns and their relations visually For example all methods that relate to a certain feature can be grouped together to form a concern Define concern in terms of other concern, overlap concerns, constraints on units relationship Hyper/J2 - compositor tool for Hyper/J style concern definition and composition Create hyperslices and hypermodules, then integrate them into existing artifact HyperProbe – insert problem detection probes into existing software Debugging tool implemented using aspects

Using CME – installation Eclipse 3.0+ Using CME – installation in Eclipse 3.0+ Click 'Help' -> 'Software Updates' -> 'Find and Install'. Select 'Search for new features to install' and click 'Next'. Click 'Add Update Site'. Enter a name for the new update site you are creating, such as "CME Update Site", and enter the URL " Click 'OK'. Fully expand the CME Update Site node that appears, and select 'CME'. Click 'Next'. Select 'The Concern Manipulation Environment x.x.x' (where "x.x.x" is the CME version number shown). Accept the license agreement

Using CME – UserInterface Using CME – User Interface The CME perspective is designed to be used for software exploration in which use of an editor (such as a code editor) is important

Using CME – Working with a project To add the CME nature to a project, right click on that project in the Package Explorer and select 'Add CME Nature'. CME will create a new concern model for the project The Concern Explorer view allows you to examine the current concern model. It deliberately resembles Eclipse's Package Explorer, so navigating it should be intuitive for Java developers. For example:

UsingCME – Queries Using CME – Queries To perform a query, the CME Search View is used. You can enter a query manually in the available text box, or you can use the CME Search dialog, which assists with the creation of basic queries To use the CME Search dialog Click the button in the CME Search view's toolbar The dialog has three tabs, which split the queries you can create into three categories - Concern Model oriented, Artifact oriented and AspectJ-style E.g. Searching for method calls with the AspectJ tab

UsingCME – Queries(cont.) Using CME – Queries (cont.) A preview of the query will be created Queries can be saved/loaded from the dialog box Click evaluate to perform the search Result dialog will appear

UsingCME – Visualizer Using CME – Visualizer The Visualiser tool provides many functions and shows an overview of where search results occur in source files

UsingCME – Addingafeature toexistingsoftware Using CME – Adding a feature to existing software Choose the package(s) you want to modify Develop the feature in a separate package, using the same classes and adding new ones if required. This is equivalent to creating a new hyperslice for the feature and implementing it Create a new concern for the feature and integrate using the composer

Using CME – adding a feature (cont.) Sample code from original package:

UsingCME – addingafeature (cont.) Using CME – adding a feature (cont.) Feature code written in a separate package:

UsingCME – adding a feature (cont.) Using CME – adding a feature (cont.) Highlight the packages in the concern explorer Right click and select "Compose New Concern “ This brings up the Compose Concern Wizard which has been filled in to compose the two concerns you selected and to handle conflicts by merging

UsingCME – adding a feature (cont.) Using CME – adding a feature (cont.) Select name for the new concern, its location and click next On the next screen click finish A new package will appear in the concern explorer with both old and new functionality inside

UsingCME – adding a feature (cont.) Using CME – adding a feature (cont.) Code after merge – a new class placed in a new package in the concern explorer

AspectJ in CME vs. standalone plug-in AspectJ composer in CME No need to write aspect code directly – code can be assembled from model Pointcut definition through query engine Uses own view perspective Visualizer AspectJ plug-in Everything must be written explicitly Pointcut definition is done through AspectJ code Standard Eclipse package explorer view Visualizer

ComponentsLayer Components Layer Reusable components for tool builders Separate paradigms and concrete tools aimed at specific tasks from concern representation Separate concern representation from language constructs API for tool developers

Components – existingitems Components – existing items Concern Composition Component (CCC) – supports different composition semantics and weaving techniques Defines interface for tools to specify what should be done where. AspectJ tool can use the API to define pointcuts Control flow relations – before/after Concern Space Management Component (Conman) – Modeling tool which represents concerns and their relationships in paradigm independent way For example we want to state that certain concern is dependent on another as a prerequisite, and we want both the AspectJ tool and the HyperJ tool know about it

FrameworksLayer Frameworks Layer Low level concern representation model Language independent – dealing with abstract object oriented language Pluggable for use with language specific drivers (engines) Defines how an artifact will be manipulated to adapt to a concern

Frameworks – existingitems Frameworks – existing items Concern Assembler Toolkit (CAT) – provides support for assembling artifacts. XML based concern assembly language Specify methods to be created Specify how methods should be combine to achieve the desired result Concern Informant Toolkit (CIT) – common interface providing information about OO elements Inheritance relations Accesibility of certain types within others Method properties Pattern Matcher (PUMA) – extensible query language processor for artifact elements Search for classes, methods, relationships, concerns Regular expressions

EnginesLayer Engines Layer Language dependent Designed to serve specific framework components Access to source code, binary or UML/XMI Most existing engines aim at Java related technology

Engines – existingitems Engines – existing items Java binary manipulator Java source manipulator XMI file manipulator XML Serializer Multiple engine attachment interface

Conclusion Pros Non intrusive Can be used with existing artifacts Extensible by tool developers Open source

Conclusion Cons AOSD is still a new concept Many components are not yet implemented Limited deployment in real world projects Heavy emphasis on specific technology, even though claimed to support wide variety