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padl [2014/02/16 07:44]
yann
padl [2019/10/06 20:37]
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-====== PADL ====== 
  
-PADL stands for Pattern and Abstract-level Description Language. It is a meta-model to describe programs at different levels of abstractions. 
- 
-===== Introduction and Usage===== 
-==== Levels of Models ==== 
- 
-There are three different levels of abstractions to model programs, collectively called abstract-level models: 
- 
-    * A ''​ICodeLevelModel''​ represents the "​raw"​ model of a program, including only data directly extractable from the program source representation (Java bytecodes, Java source code, C/C++ source code...); 
- 
-    * A ''​IIdiomLevelModel''​ represents a model of a program where some idioms have been reified, typically binary-class relationships computed using some ''​padl.analysis.repository.AACRelationshipsAnalysis'',​ and some extra data have been added, for example the length of the methods, obtained using ''​padl.statement.creator.classfiles.LOCModelAnnotator'',​ or information about conditional statements, obtained using ''​padl.statement.creator.classfiles.ConditionalModelAnnotator''​. 
- 
-    * A ''​IDesignLevelModel''​ represents a model of a program where design information is available. Typical design information is obtained from the idiom-level model, for example occurrences of design motifs or of code and design smells. 
- 
-    * A ''​IDesignMotif''​ represents a design motif, i.e., the solution to a design pattern model in ''​PADL Design Motifs''​. 
- 
-The following diagram shows the hierarchy of the interface describing models. (This hierarchy has been built using the project ''​Ptidej UI Viewer Standalone Swing''​) The root of the models is the interface ''​IAbstractModel'',​ which describes any model that could be handled by most of Ptidej analyses and tools. This interface abstracts ''​IAbstractLevelModel'',​ which represents models of programs, and ''​IDesignMotif'',​ which represents models of design motifs. 
- 
-{{:​abstractmodels2.jpg|Abstract Models}} 
- 
-The ''​PADL''​ project also provides the interfaces: 
-    * ''​IAbstractModelSerialiser''​ must be implemented by any algorithm to serialise/​deserialise PADL models. A variety of serialisers already exist, including for popular databases, such as [[http://​www.db4o.com/​|DB4O]] and [[http://​neodatis.wikidot.com/​|NeoDatis]];​ 
-    * ''​ICodeLevelModelCreator'',​ along with ''​padl.kernel.ICodeLevelModel.create(ICodeLevelModelCreator)'',​ is an implementation of the Builder design pattern, to provide a unified interface to create PADL models. Creators exist for Java bytecodes and source code as well as other programming languages, such as C/C++. 
- 
-==== How to Create a PADL Model from Java Bytecodes? ==== 
- 
-The PADL meta-model (Pattern and Abstract-level Description Language) is a semi-language independent meta-model. It is at the core of the Ptidej Tool Suite. It provides a set of interface and a reference implementation of the meta-model. It also provides several parsers to create PADL models from various representations of programs: AOL, AspectJ, C++, Java (byte-code),​ Eclipse JDT Project, and MSE files. 
- 
-A PADL model is typically created using the following code: 
- 
-<​code>​ 
- final ICodeLevelModel codeLevelModel = 
-   ​Factory.getInstance().createCodeLevelModel("​A"​);​ 
- ​codeLevelModel.create( 
-   new CompleteClassFileCreator( 
-   ​DefaultFileRepository.getInstance(),​ 
-       new String[] { "​dir1/​dir2/​A.class"​ }), true); 
-</​code>​ 
- 
-In general, a code-level model can be obtain for a system through reverse-engineering/​parsing using: 
- 
-<​code>​ 
- final ICodeLevelModel codeLevelModel = 
-   ​Factory.getInstance().createCodeLevelModel(A Name); 
- ​codeLevelModel.create( 
-   new A Creator( 
-   A File Repository.getInstance(),​ 
-       new String[] { Some files }), Recurse in directories);​ 
-</​code>​ 
- 
-where: 
- 
-    * A Name can be any String; 
-    * A Creator is any class implementing the ICodeLevelModelCreator interface. A creator is the concrete parser or reverse-engineering algorithm that builds a PADL model from some files. So far, they are creators for AOL, C++, Java, Eclipse JDT Projects, and MSE files. The ICodeLevelModelCreator is a typical implementation of the Builder design pattern. 
-    * A File Repository is any class implementing the IFileRepository interface. A file repository allows the meta-model and the creator to access necessary PADL resources (constituents,​ analyses, etc.) in a platform-independent way. So far, two repositories exist, one to access files on disk, one to access files in a JAR file. 
-    * Some files are any String pointing towards the files/​directories to be parsed, as required by the creator. 
-    * Recurse in directories is a Boolean flag that allow you to specify only the top most directory of a set of source files. 
- 
-Each constituent of a model has a unique ID, obtained using the getID() method. Navigation through a model is typically performed using recursive calls to the getIteratorOnActors() and getIteratorOnConcurrentActors() methods. (The [[PADL Creator ClassFile]] project provides two methods to retrieve (and create if needed) member entities: Utils.searchForEntity(...) and Utils.searchForEnclosingEntity(...). However, these methods should be used as little as possible as they potentially return new instances of IMemberClass (or IMemberInterface or IMemberGhost). Using these methods outside of the creator would be a Dirty Hack!). 
- 
- 
- 
- 
-==== How to Create a PADL Model from Java Source Code? ==== 
- 
-A third-party project provides a means to create a PADL model from source code (instead of class files). Fetch PADL Creator Java from the SVN and use the following idiom: 
- 
-<​code>​ 
- new padl.creator.CreatorJava(DiagnosticListener,​ 
-                              Options, 
-                              Files) 
-                             ​.create(Model);​ 
-</​code>​ 
- 
-Each argument is described in the JavaDoc of the padl.creator.CreatorJava class. 
- 
- 
- 
- 
-==== How to Traverse a PADL Model using a Visitor? ==== 
- 
-The PADL meta-model provides you with two distinct but related visitors: IWalker and IGenerator. Both visitors inherit from IVisitor but provide different methods to retreive the results of the visit: getResult() and getCode() respectively. A typical example of using one of these visitors is: 
- 
-<​code>​ 
-final IWalker walker = new InheritanceImplementationCounter();​ 
-final ICodeLevelModel codeLevelModel = 
-     ​Primitive.getFactory().createCodeLevelModel(""​);​ 
- ​codeLevelModel.create( 
-    new CompleteClassFileCreator( 
-        DefaultFileRepository.getInstance(),​ 
-        new String[] { path }, 
-        true)); 
-final IIdiomLevelModel idiomLevelModel = 
-   ​(IIdiomLevelModel) new AACRelationshipsAnalysis().invoke(codeLevelModel);​ 
- 
-walker.reset();​ 
-idiomLevelModel.walk(walker);​ 
-System.out.println(walker.getResult());​ 
-</​code>​ 
- 
-Obviously, the class InheritanceImplementationCounter implements IWalker. 
- 
- 
- 
- 
-===== API ===== 
-==== Binary Class Relationships ==== 
- 
-The PADL meta-model includes an extensive hierarchy of interfaces to describes binary class relationships. The following figure highlights these relationships. Of particular interest are the following relationships,​ presented in order from the most constraining to the least constraining. Whenever a relationship is identified between two entities, the following least constraining relationships are not included. For example, if an aggregation relationships exists between two classes A and B, no corresponding use relationship would exist. 
- 
-    * IContainerComposition describes a relationship between two classes A and B such as A holds the unique reference(s) to (an) instance(s) of B and plays the role of container, providing method to add/remove instances of B. 
- 
-    * IComposition describes a relationship between two classes A and B such as A holds the unique reference(s) to (an) instance(s) of B. 
- 
-    * IContainerAggregation describes a relationship between two classes A and B such as A holds (possibly shared) reference(s) to (an) instance(s) of B and plays the role of container, providing method to add/remove instances of B. 
- 
-    * IAggregation describes a relationship between two classes A and B such as A holds (possibly shared) reference(s) to (an) instance(s) of B. 
- 
-    * IAssociation a relationship between two classes A and B such as A calls some methods of B using (an) instance(s) of B. 
- 
-    * ICreation a relationship between two classes A and B such as A create (an) instance(s) of B. 
- 
-    * IUseRelationship a relationship between two classes A and B such as A uses in some way, for example by declaring a method with a parameter of type B, (an) instance(s) of class B. 
- 
-{{:​relationships.gif|Relationships}} 
- 
-The existence of binary class relationships is inferred from an ICodeLevelModel based on the presence of certain fields and methods and method invocations in classes by the AACRelationshipsAnalysis. 
- 
- 
- 
- 
-==== Method Invocations ==== 
- 
-As part of an effort to improve code representation in PADL. The concept of method invocation has been added since 2004-2005. An interface IMethodInvocation represents method invocations. This concept is as-of-today not quite clean and is used to describes both method invocations and field accesses. Therefore, the interface IMethodInvocation (and its reference implementation) includes: 
- 
-    * a IMethod container that is the calling method (in which the method invocation can be found.) (Dirty Hack.) 
- 
-    * a int cardinality that describes the cardinality of the call 
-      * 1 = unique call; 
-      * 2 = repetitions of the call; 
- 
-    * a int type that characterises the type of method invocation: 
-      * CLASS_CLASS:​ method invocation from a class method to another class method; 
-      * CLASS_CLASS_FROM_FIELD:​ method invocation from a class method to another class method through a class variable; 
-      * CLASS_INSTANCE:​ method invocation from a class method to an instance method; 
-      * CLASS_INSTANCE_FROM_FIELD:​ method invocation from a class method to an instance method through a class variable; 
-      * INSTANCE_CLASS:​ method invocation from an instance method to a class method; 
-      * INSTANCE_CLASS_FROM_FIELD:​ method invocation from an instance method to a class method through an instance variable; 
-      * INSTANCE_CREATION:​ creation of a new instance; 
-      * INSTANCE_INSTANCE:​ method invocation from an instance method to another instance method; 
-      * INSTANCE_INSTANCE_FROM_FIELD:​ method invocation from an instance method to another instance method through an instance variable; 
-      * OTHER: other things... such as field accesses! ([[Dirty Hack]].) 
- 
-    * IEntity targetEntity:​ the entity declaring the called method. ([[Dirty Hack]].) 
- 
-    * int visibility: the visibility of the called method. ([[Dirty Hack]].) 
- 
-    * IAbstractMethod calledMethod:​ a reference to the called method. 
- 
-    * List callingFields:​ a list of the fields (if any) through which the called method is invoked. ([[Fragile Code]].) 
- 
-    * IEntity fieldDeclaringEntity:​ a reference to the IEntity declaring the (last) field through which the called method is invoked. ([[Dirty Hack]].) 
- 
- 
- 
- 
-==== The getID() and getName() Methods ==== 
- 
-Although the getID(), getName(), and getPath() methods form a trio, they have different semantics. The getID() must return a unique identifier for each constituent in a model. The getName() returns the name of a constituent. For binary class relationships and method invocations,​ the name returned by getName() is less important, it could simply be Method Invocation, for example. (Their ID must still be unique, though.) 
- 
-Here are some examples of getID() : 
- 
-    * padl for a package; 
- 
-    * getName() for a method; 
- 
-    * setName(java.lang.String) for a method; 
- 
-    * addA(int, padl.example.aggregation.A) for a method; 
- 
-    * name for an attribute. 
- 
-    * Member for a member class, member interface, or member ghost. 
- 
-Here are some examples of getName() : 
- 
-    * padl for a package; 
- 
-    * getName for a method; 
- 
-    * setName for a method; 
- 
-    * addA for a method; 
- 
-    * name for an attribute. 
- 
-    * Member for a member class, member interface, or member ghost. 
- 
- 
- 
-==== The getPath() Method and the padl.path.Finder Class ==== 
- 
-The paths are used to represent how to get to a constituent within a model. 
- 
-The paths start with a '/'​ and the name of the model (optional). 
- 
-Then, each constituent to go through until the target is specified the same way: 
- 
-   - the '​|'​ character, 
-   - the (simple) name of the interface in padl.kernel of the constituent (or one of its super-interface,​ but always in padl.kernel),​ 
-   - the ':'​ character, 
-   - a constituent specific part: 
-     * If the constituent is an Operation, its name, a '​(',​ the list of the TypeName of the types of its arguments separated by a ','​ (if any), a '​)'​ 
-     * Its name otherwise 
- 
-The class padl.path.Finder can be used to walk the paths. 
padl.txt ยท Last modified: 2019/10/06 20:37 (external edit)