LOG8430 : Architecture logicielle et conception avance Yann-Gal - - PowerPoint PPT Presentation
LOG8430 : Architecture logicielle et conception avance Yann-Gal Guhneuc Bibliothques et le chargement de composantes dynamiques (Contributeurs : Guhneuc 2009-2015 ; Khomh 2009-2014 ; Soh 2012-2014) This work is licensed under a
This work is licensed under a Creative Commons Attribution-NonCommercial- ShareAlike 3.0 Unported License
Bibliothèques et le chargement de composantes dynamiques
(Contributeurs : Guéhéneuc 2009-2015 ; Khomh 2009-2014 ; Soh 2012-2014)
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Présentation des fiches de lecture Fin du cours sur la qualité des programmes Bibliothèques et le chargement de
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Présentation des fiches de lecture Fin du cours sur la qualité des programmes Bibliothèques et le chargement de
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Présentation des fiches de lecture Fin du cours sur la qualité des
Bibliothèques et le chargement de
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Présentation des fiches de lecture Fin du cours sur la qualité des programmes Bibliothèques et le chargement de
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1.
Introduction
2.
Bibliothèques et cadriciels
– Types d’interconnexions – Problèmes légaux – Chargement dynamique
3.
Réflexion
4.
Théorie
– Méta-classes – Protocoles de méta-objets (MOP) – MOP à la compilation, à l’exécution
5.
Retour sur le chargement dynamique
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1.
Introduction
2.
Bibliothèques et cadriciels
– Types d’interconnexions – Problèmes légaux – Chargement dynamique
3.
Réflexion
4.
Théorie
– Méta-classes – Protocoles de méta-objets (MOP) – MOP à la compilation, à l’exécution
5.
Retour sur le chargement dynamique
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Aucun logiciel de grande taille n’est
Utilisation de
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Utilisation de
Problèmes
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1.
Introduction
2.
Bibliothèques et cadriciels
– Types d’interconnexions – Problèmes légaux – Chargement dynamique
3.
Réflexion
4.
Théorie
– Méta-classes – Protocoles de méta-objets (MOP) – MOP à la compilation, à l’exécution
5.
Retour sur le chargement dynamique
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« Bibliothèque [library] logicielle est un ensemble de
fonctions utilitaires, regroupées et mises à disposition afin de pouvoir être utilisées sans avoir à les réécrire » [Wikipedia]
– Plutôt que de coder une procédure courante dans chaque programme en ayant besoin, on rassemble ces procédures dans des bibliothèques – Si un programme a une fonction à remplir et que celle-ci se trouve en bibliothèque, il l'utilisera directement – Les bibliothèques logicielles se distinguent des exécutables dans la mesure où elles ne représentent pas une application – Exemples
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L'organisation classique des bibliothèques se fait
– Bibliothèques de bas niveau ou bibliothèques système : elles fournissent des services d'interface avec le système d'exploitation, avec les périphériques, ou fournissent des outils génériques
de fichiers, de périphériques d'entrée/sortie comme le clavier, l'écran, etc.
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– Bibliothèques de haut niveau, aussi appelées bibliothèques métier, elles interagissent avec celles de bas niveau : les fonctions qu'elles contiennent sont propres à une activité spécifique
de gérer, d'animer et d'afficher des objets graphiques complexes
– OpenGL
fonctions destinées à structurer l'information dans une image à des fins d'analyse
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Autres bibliothèques
– Combinateurs en programmation fonctionnelle – Protocoles de méta programmation
Les bibliothèques offrent une interface de programmation
(API), permettant aux programmeurs de choisir les fonctions
– API est la « partie visible » d'une bibliothèque ou d'un ensemble de bibliothèques – Les API se présentent comme une liste des noms des fonctions
paramètres à leur fournir et sur les résultats retournés
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« Un cadriciel [framework] est un espace de
Un framework fournit
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Un cadriciel fournit un contexte où les composants sont
réutilisés
– Bibliothèque/Library = ensemble des fonctions – Cadriciel/Framework
suivant MVC)
– Exemples
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On trouve différents types de cadriciels
– Cadriciel d'infrastructure système : pour développer des systèmes d'exploitation, des interfaces graphiques, des outils de communication
– Cadriciel d'intégration intergicielle (middleware) : pour fédérer des applications hétérogènes. Pour mettre à dispositions différentes technologies sous la forme d'une interface unique
– Cadriciel d'entreprise : pour développer des applications spécifiques au secteur d'activité de l'entreprise
– Cadriciel orientés système de gestion de contenu
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1.
Introduction
2.
Bibliothèques et cadriciels
– Types d’interconnexions – Problèmes légaux – Chargement dynamique
3.
Réflexion
4.
Théorie
– Méta-classes – Protocoles de méta-objets (MOP) – MOP à la compilation, à l’exécution
5.
Retour sur le chargement dynamique
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Clients–Libraries/Frameworks
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Linking
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Forking
– Typical in most languages – Process duplication
process
final StringBuffer commandLine = new StringBuffer(); commandLine.append("..\\DOT\\bin\\dotty "); commandLine.append(aFilePath); final Process process = Runtime.getRuntime().exec(commandLine.toString()); final OutputMonitor errorStreamMonitor = new OutputMonitor(...,process.getErrorStream(),...); errorStreamMonitor.start(); final OutputMonitor inputStreamMonitor = new OutputMonitor(...,process.getInputStream(),...); inputStreamMonitor.start(); try { process.waitFor(); } catch (final InterruptedException ie) { ie.printStackTrace( Output.getInstance().errorOutput()); } if (process.exitValue() != 0) { ... }
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IPC
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package kr.ac.yonsei.cse3009.rpc; import java.net.URL; import org.apache.xmlrpc.client.XmlRpcClient; import org.apache.xmlrpc.client.XmlRpcClientConfigImpl; public class Client { public static void main(final String[] args) throws Exception { final XmlRpcClientConfigImpl config = new XmlRpcClientConfigImpl(); config.setServerURL( new URL("http://127.0.0.1:8080/xmlrpc")); final XmlRpcClient client = new XmlRpcClient(); client.setConfig(config); final Object[] params = new Object[] { new Integer(33), new Integer(9) }; final Integer result = (Integer) client.execute("Calculator.add", params); System.out.println(result); } } package kr.ac.yonsei.cse3009.rpc; import org.apache.xmlrpc.server.PropertyHandlerMapping; import org.apache.xmlrpc.server.XmlRpcServer; import org.apache.xmlrpc.webserver.WebServer; public class Server { public static void main(final String[] args) throws Exception { final WebServer webServer = new WebServer(8080); final XmlRpcServer xmlRpcServer = webServer.getXmlRpcServer(); final PropertyHandlerMapping phm = new PropertyHandlerMapping(); phm.addHandler("Calculator", Calculator.class); xmlRpcServer.setHandlerMapping(phm); webServer.start(); } } package kr.ac.yonsei.cse3009.rpc; public class Calculator { public int add(final int i1, final int i2) { return i1 + i2; } public int sub(final int i1, final int i2) { return i1 - i2; } }
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Subclassing
– Typical in most object-
– Structural, static relation
public class OutputMonitor extends Thread { ... public OutputMonitor(...) { this.setName(threadName); this.setPriority(Thread.MAX_PRIORITY); ... } public void run() { try { int value = 0; byte[] bytes; char lastWrittenChar; while ((value = this.inputStream.read()) > 0) { synchronized (System.err) { synchronized (System.out) { if (value != 13 && value != 10) { lastWrittenChar = (char) value; ... }} } } catch (final IOException ioe) { ...
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Subclassing
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Subclassing
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Template Hooks
public abstract class TestCase extends Assert implements Test { public void runBare() throws Throwable { setUp(); try { runTest(); } finally { tearDown(); } } protected void setUp() throws Exception { } protected void tearDown() throws Exception { } ... }
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Subclassing
(Only Singleton does not explicitly use subclassing)
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Patrons de conception [Gamma et al.]
– Usine abstraite (Abstract Factory) – Adapteur (Adapter) – Pont (Bridge) – Constructeur (Builder)
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Patrons de conception [Gamma et al.]
– Décorateur (Decorator) – Méthode usine (Factory Method) – Itérateur (Iterator) – Observateur (Observer)
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Patrons de conception [Gamma et al.]
– Méthode gabarit (Template Method) – Visiteur (Visitor)
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Dynamic loading
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Poor man’s profiler
– Calls the main() method of a class whose name is given at runtime, by the user – Displays the time spent in the called method
public final class PoorManProfiler { public static void main(final String[] args) { try { final Class toBeRun = Class.forName(args[0]); final Method mainMethod = toBeRun.getMethod("main", new Class[] { String[].class }); final long startTime = System.currentTimeMillis(); mainMethod.invoke(null, new Object[] { new String[0] }); final long endTime = System.currentTimeMillis(); System.out.println(); System.out.println(endTime - startTime); } catch (final Exception e) { e.printStackTrace(); } } }
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1.
Introduction
2.
Bibliothèques et cadriciels
– Types d’interconnexions – Problèmes légaux – Chargement dynamique
3.
Réflexion
4.
Théorie
– Méta-classes – Protocoles de méta-objets (MOP) – MOP à la compilation, à l’exécution
5.
Retour sur le chargement dynamique
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Problèmes légaux
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Problèmes légaux
– « La redistribution […] doit reproduire la note de droit d’auteur ci-dessus […] » – « Tous les produits publicitaires doivent inclure […] » – « Ni le nom de l’auteur ni ceux des contributeurs […] »
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Problèmes légaux
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Problèmes légaux
doit être sous licence GPL 2 »
produit dérivés de S soit sous MPL1.1 ou futures MPL
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1.
Introduction
2.
Bibliothèques et cadriciels
– Types d’interconnexions – Problèmes légaux – Chargement dynamique
3.
Réflexion
4.
Théorie
– Méta-classes – Protocoles de méta-objets (MOP) – MOP à la compilation, à l’exécution
5.
Retour sur le chargement dynamique
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En deux mots
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Chargeur de classes
Les classes chargées
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Charger une classe à
– Classe enveloppante (wrapper)
Appeler une méthode
Charger une classe vs.
public final class WrapperMain { public static void main(String[] args) { try { Class toBeRun = Class.forName(args[0]); Method mainMethod = toBeRun.getMethod("main", new Class[] { String[].class }); final long startTime = System.currentTimeMillis(); mainMethod.invoke(null, new Object[] { new String[0] }); final long endTime = System.currentTimeMillis(); System.out.println(); System.out.println(endTime - startTime); } catch (final Exception e) { e.printStackTrace( Output.getInstance().errorOutput()); } } }
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Reflection enables dynamic loading
C-based operating systems, such as AmigaOS, Linux, UN*X, Windows…
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1.
Introduction
2.
Bibliothèques et cadriciels
– Types d’interconnexions – Problèmes légaux – Chargement dynamique
3.
Réflexion
4.
Théorie
– Méta-classes – Protocoles de méta-objets (MOP) – MOP à la compilation, à l’exécution
5.
Retour sur le chargement dynamique
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Reflection is the ability of a computer
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Scenario 1: invoke an arbitrary method on
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Scenario 2: access the complete (including
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Scenario 3: count the number of instances of
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Scenario 4: patch the method of a class to
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Scenario 1:
– Given a class C – Given an object o, instance of C – Identify all the methods available on o – Invoke a method using its name foo public class C { private int i; public C(final int anInt) { this.i = anInt; } public void foo(final String s) { System.out.print(s); System.out.println(this.i); } }
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Scenario 1:
– Given a class C – Given an object o, instance of C – Identify all the methods available on o – Invoke a method using its name foo Identify all the methods available on o foo getClass hashCode equals toString notify notifyAll wait wait wait Invoke a method using its name foo This is foo: 42
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Scenario 1:
– Given a class C – Given an object o, instance of C – Identify all the methods available on o – Invoke a method using its name foo final C o = new C(42); System.out.println("Identify all the methods available on o"); final Class<?> classOfO = o.getClass(); final Method[] methodsOfC = classOfO.getMethods(); for (int i = 0; i < methodsOfC.length; i++) { final Method method = methodsOfC[i]; System.out.print('\t'); System.out.println(method.getName()); } System.out.println("Invoke a method using its name foo"); final Method fooMethod = classOfO.getMethod("foo", new Class[] { String.class }); fooMethod.invoke(o, new Object[] { "\tThis is foo: " });
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Scenario 1:
– Given a class C – Given an object o, instance of C – Identify all the methods available on o – Invoke a method using its name foo Identify all the methods available on o foo getClass hashCode equals toString notify notifyAll wait wait wait Invoke a method using its name foo This is foo: 42
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Scenario 2:
– Given an object o, instance of C – Save on disk the complete state of o – Restore from disk the object o at a later time public class C { private int i; public C() { this(-1); } public C(final int anInt) { this.i = anInt; } public void foo(final String s) { System.out.print(s); System.out.println(this.i); } }
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Scenario 2:
– Given an object o, instance of C – Save on disk the complete state of o – Restore from disk the object o at a later time Save on disk the complete state of o i = 42 Restore from disk the object o at a later time This is foo on o2: 43
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Scenario 2:
– Given an object o, instance of C – Save on disk the complete state of o – Restore from disk the object o at a later time final C o1 = new C(42); System.out.println("Save on disk the complete state of o"); final Class<?> classOfO = o1.getClass(); final Field[] fieldsOfC = classOfO.getDeclaredFields(); for (int i = 0; i < fieldsOfC.length; i++) { final Field field = fieldsOfC[i]; field.setAccessible(true); System.out.print('\t' + field.getName()); System.out.println(" = " + field.getInt(o1)); } System.out.println("Restore from disk the object o at a later time"); final C o2 = (C) classOfO.newInstance(); final Field fieldiOfC = classOfO.getDeclaredField("i"); fieldiOfC.setAccessible(true); fieldiOfC.setInt(o2, 43);
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Scenario 2:
– Given an object o, instance of C – Save on disk the complete state of o – Restore from disk the object o at a later time Save on disk the complete state of o i = 42 Restore from disk the object o at a later time This is foo on o2: 43
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Scenario 3:
– Given a class C – Record the numbers of its instance ever created – Report this number when the program ends public class C { private static int numberOfInstances; public static int getNumberOfInstances() { return C.numberOfInstances; } private int i; public C() { this(-1); } public C(final int anInt) { C.numberOfInstances++; this.i = anInt; } public void foo(final String s) { System.out.print(s); System.out.println(this.i); } }
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Scenario 3:
kr.ac.yonsei.it.cse3009.reflection.scenario3.C@150bd4d kr.ac.yonsei.it.cse3009.reflection.scenario3.C@1bc4459 kr.ac.yonsei.it.cse3009.reflection.scenario3.C@12b6651 3 – Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
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Scenario 3:
public class Main { public static void main(final String[] args) { final C o1 = new C(42); final C o2 = new C(1); final C o3 = new C(100); System.out.println(o1 + "\n" + o2 + '\n' + o3); System.out.println(C.getNumberOfInstances()); } } – Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
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Scenario 3:
kr.ac.yonsei.it.cse3009.reflection.scenario3.C@150bd4d kr.ac.yonsei.it.cse3009.reflection.scenario3.C@1bc4459 kr.ac.yonsei.it.cse3009.reflection.scenario3.C@12b6651 3
– Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
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Class Class is a metaclass
Class Method is a class
Class Field is a class
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Class Class is a metaclass
Class Method is a class
Class Field is a class
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Class Class is a metaclass
Class Method is a class
Class Field is a class
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We never modified class Class
We used static fields and methods to count
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Scenario 4:
public interface I { public void foo(final String s); } public class C implements I { private int i; public C(final int anInt) { this.i = anInt; } public void foo(final String s) { System.out.print(s); System.out.println(this.i); } } – Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo()
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Scenario 4:
This is o: 42 Forwarding method: "foo" Original arguments: "This is o: " New arguments: "THIS IS O: " THIS IS O: 42 – Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo()
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Scenario 4:
final I o = new C(42);
final InvocationHandler handler = new InvokationHandler(o); final I proxy = (I) Proxy.newProxyInstance( I.class.getClassLoader(), new Class[] { I.class }, handler); Assert.assertTrue(proxy instanceof I); Assert.assertFalse(proxy instanceof C); Assert.assertTrue(proxy.equals(o)); proxy.foo("This is o: "); – Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo()
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Scenario 4:
public class InvokationHandler implements InvocationHandler { private final I i; public InvokationHandler(final I aConcreteImplementationOfI) { this.i = aConcreteImplementationOfI; } public Object invoke( final Object aProxy, final Method aMethod, final Object[] someArgs) throws Throwable { if (aMethod.getName().equals("foo")) { final String arg = (String) someArgs[0]; final String newArg = arg.toUpperCase(); System.out.print("Forwarding method: \""); System.out.print(aMethod.getName()); System.out.print("\"\n\tOriginal arguments: \""); System.out.print(arg); System.out.print("\"\n\tNew arguments: \""); System.out.print(newArg); System.out.println('\"'); this.i.foo(newArg); return null; } else { return aMethod.invoke(this.i, someArgs); } } } – Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo()
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Scenario 4:
final I o = new C(42);
final InvocationHandler handler = new InvokationHandler(o); final I proxy = (I) Proxy.newProxyInstance( I.class.getClassLoader(), new Class[] { I.class }, handler); Assert.assertTrue(proxy instanceof I); Assert.assertFalse(proxy instanceof C); Assert.assertTrue(proxy.equals(o)); proxy.foo("This is o: ");
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo()
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Smalltalk
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Smalltalk
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Smalltalk
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Smalltalk
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Scenario 1:
– Given a class C – Given an object o, instance of C – Identify all the methods available on o – Invoke a method using its name foo Object subclass: #C instanceVariableNames: 'i' classVariableNames: '' poolDictionaries: '' category: 'CSE3009'. C class compile: 'newWithi: anInt ^(self new) i: anInt ; yourself.'. C compile: 'foo: aText Transcript show: aText. Transcript show: i. Transcript cr.'. C compile: 'i: anInt i := anInt.'.
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Scenario 1:
– Given a class C – Given an object o, instance of C – Identify all the methods available on o – Invoke a method using its name foo Identify all the methods available on o an IdentitySet(#handles: #longPrintString #actionMap #hasContentsInExplorer [...] #foo: [...] #i: [...] #creationStamp) Invoke a method using its name foo This is foo: 42
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Scenario 1:
– Given a class C – Given an object o, instance of C – Identify all the methods available on o – Invoke a method using its name foo |o|
Transcript show: 'Identify all the methods available on o' ; cr. Transcript show: C allSelectors ; cr. Transcript show: 'Invoke a method using its name foo' ; cr. (C compiledMethodAt: #foo:) valueWithReceiver: o arguments: #('This is foo: ').
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Scenario 2:
– Given an object o, instance of C – Save on disk the complete state of o – Restore from disk the object o at a later time Object subclass: #C instanceVariableNames: 'i' classVariableNames: '' poolDictionaries: '' category: 'CSE3009'. C class compile: 'newWithi: anInt ^(self new) i: anInt ; yourself.'. C compile: 'foo: aText Transcript show: aText. Transcript show: i. Transcript cr.'. C compile: 'i: anInt i := anInt.'.
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Scenario 2:
– Given an object o, instance of C – Save on disk the complete state of o – Restore from disk the object o at a later time Save on disk the complete state of o 42 Restore from disk the object o at a later time This is foo on o2: 43
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Scenario 2:
– Given an object o, instance of C – Save on disk the complete state of o – Restore from disk the object o at a later time |o1 o2|
Transcript show: 'Save on disk the complete state of o' ; cr. Transcript show: (o1 instVarAt: 1) ; cr. Transcript show: 'Restore from disk the object o at a later time' ; cr.
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Scenario 2:
– Given an object o, instance of C – Save on disk the complete state of o – Restore from disk the object o at a later time 1@2 serializeToFileNamed: 'hello.fuel'. FLMaterializer materializeFromFileNamed: 'hello.fuel'
Thanks to Marcus Denker for pointing out these helper methods
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Scenario 3:
Object subclass: #C instanceVariableNames: 'i' classVariableNames: 'NumberOfInstances' poolDictionaries: '' category: 'CSE3009'. C class compile: 'newWithi: anInt ^(self new) i: anInt ; yourself.'. C compile: 'foo: aText Transcript show: aText. Transcript show: i. Transcript cr.'. C compile: 'i: anInt i := anInt.'. – Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
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Scenario 3:
C class compile: 'newWithi: anInt ^(self new) i: anInt ; yourself.'. C compile: 'foo: aText Transcript show: aText. Transcript show: i. Transcript cr.'. C compile: 'i: anInt i := anInt.'.
– Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
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Scenario 3:
C class compile: 'initialize NumberOfInstances := 0.'. C class compile: 'new NumberOfInstances := NumberOfInstances + 1. ^ self basicNew initialize.'. C class compile: 'numberOfInstances ^ NumberOfInstances.'. – Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
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Scenario 3:
|o1 o2 o3| C initialize.
Transcript show: o1 ; show: ' ' ; show: o2 ; show: ' ' ; show: o3 ; cr. Transcript show: C numberOfInstances. – Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
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Scenario 3:
a C a C a C 3
– Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
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Scenario 3:
class variables and class methods
belong to the class (thus unique)
– Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
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Scenario 3:
a C a C a C 3 – Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
Thanks to Christophe Dony for suggesting this use of class vs. class instance variables
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Scenario 3:
its declaring class… and its subclasses!
final D o4 = new D(); // Eclipse advises to use C to call getNumberOfInstances(). System.out.println(o4); System.out.println(D.getNumberOfInstances()); – Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
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Scenario 3:
– A class variable is shared by all the instance of the class and all the instances of its subclasses – A class instance variable is unique to each class, inherited from the super-class, like instance variables
C class instanceVariableNames: 'IndividualClassNumberOfInstances' – Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
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Scenario 3:
C subclass: #D instanceVariableNames: '' classVariableNames: '' poolDictionaries: '' category: 'Ptidej'. D class compile: 'initialize IndividualClassNumberOfInstances := 0.'. D class compile: 'new NumberOfInstances := NumberOfInstances + 1. IndividualClassNumberOfInstances := IndividualClassNumberOfInstances + 1. ^ self basicNew initialize.'. D class compile: 'numberOfInstances ^ NumberOfInstances.'. D class compile: 'individualClassNumberOfInstances ^ IndividualClassNumberOfInstances.'. – Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
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Scenario 3:
| o4 | D initialize.
Transcript show: o4 ; cr. Transcript show: C numberOfInstances ; cr. Transcript show: D numberOfInstances ; cr. Transcript show: D individualClassNumberOfInstances ; cr. – Given a class C – Record the numbers of its instance ever created – Report this number when the program ends a D 4 4 1
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Scenario 3:
Interface of the Java Platform Debug Architecture
JVM and to obtain their instances
com.sun.jdi.ReferenceType.instances(long)
constructs of the language
– Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
http://stackoverflow.com/questions/1947122/ is-there-a-simple-way-of-obtaining-all-object-instances-of-a-specific-class-in-j/1947200#1947200
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Scenario 3:
Transcript show: (C allInstances size). – Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
Thanks to Marcus Denker for pointing out this solution
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo() Object subclass: #C instanceVariableNames: 'i' classVariableNames: '' poolDictionaries: '' category: 'CSE3009'. C class compile: 'newWithi: anInt ^(self new) i: anInt ; yourself.'. C compile: 'foo: aText Transcript show: aText. Transcript show: i. Transcript cr.'. C compile: 'i: anInt i := anInt.'.
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo() This is o: 42 Intercepting message send: foo: Original arguments: This is o: New arguments: THIS IS O: THIS IS O: 42
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Scenario 4:
Kernel#ObjectTracer
PBE1/PBE1ch15.html
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo()
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Scenario 4:
Kernel#ObjectTracer
PBE1/PBE1ch15.html
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo()
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo() | o aWrapper |
aWrapper := WrapperForC on: o. "o become: aWrapper." aWrapper foo: 'This is o: '. aWrapper xxxUnTrace.
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo() ObjectTracer subclass: #WrapperForC instanceVariableNames: '' classVariableNames: '' poolDictionaries: '' category: 'CSE3009'. WrapperForC compile: 'doesNotUnderstand: aMessage "Intercept the selector foo:" | sel arg newArg | sel := aMessage selector. sel = ''foo:'' ifTrue: [ arg := (aMessage arguments) at: 1. newArg := arg asUppercase. Transcript show: ''Intercepting message send: '' ; show: sel ; cr. Transcript tab ; show: ''Original arguments: '' ; show: arg ; cr. Transcript tab ; show: ''New arguments: '' ; show: newArg ; cr. aMessage argument: newArg. aMessage sendTo: (self xxxViewedObject) ] ifFalse: [ "Transcript show: aMessage." ]'.
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo() This is o: 42 Intercepting message send: foo: Original arguments: This is o: New arguments: THIS IS O: THIS IS O: 42 | o aWrapper |
aWrapper := WrapperForC on: o. "o become: aWrapper." aWrapper foo: 'This is o: '. aWrapper xxxUnTrace.
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo()
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo()
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Scenario 4:
Kernel#ObjectTracer
PBE1/PBE1ch15.html
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo()
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Reflectivity
reflection: method bodies are first-class
implementation of Partial Behavioural Reflection
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo() Object subclass: #C instanceVariableNames: 'i' classVariableNames: '' poolDictionaries: '' category: 'CSE3009'. C class compile: 'newWithi: anInt ^(self new) i: anInt ; yourself.'. C compile: 'foo: aText Transcript show: aText. Transcript show: i. Transcript cr.'. C compile: 'i: anInt i := anInt.'.
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo() nodes := (C>>#foo:) sends select: [:each | ((each selector ~= #show:)
ifTrue: [ false ] ifFalse: [ (each arguments at: 1) name = 'aText'. ]. ].
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo() gpLink := GPLink metaObject: [:arg1 :node | | newArg | newArg := arg1 asUppercase. Transcript show: 'Intercepting message send: '. Transcript show: node ; cr. Transcript tab ; show: 'Original arguments: '. Transcript show: arg1 ; cr. Transcript tab ; show: 'New arguments: '. Transcript show: newArg ; cr. Transcript show: newArg. ]. gpLink control: #instead.
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo()
nodes do: [:node | node link: gpLink].
gpLink uninstall. This is o: 42 Intercepting message send: foo: Original arguments: This is o: New arguments: THIS IS O: THIS IS O: 42
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Scenarios 1, 2, 3, and 4
c-not-have-reflection
2005/n1751.html
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Scenarios 1, 2, 3, and 4
lib/html/index.html#introduction
us/library/y0114hz2%28v=vs.110%29.aspx
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Scenarios 1, 2, 3, and 4
lib/html/index.html#introduction
us/library/y0114hz2%28v=vs.110%29.aspx
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Mirror
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Scenario 1:
– Given a class C – Given an object o, instance of C – Identify all the methods available on o – Invoke a method using its name foo namespace cse3009 { class C { private: int i; public: C(const int _i) : i(_i) { } int get_i(void) const { return this->i; } void set_i(const int _i) { this->i = _i; } void foo(const std::string _s) const { std::cout << _s << this->i << std::endl; } }; }
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Scenario 1:
– Given a class C – Given an object o, instance of C – Identify all the methods available on o – Invoke a method using its name foo Identify all the methods available on o (The type of o is cse3009::C) cse3009::C::i cse3009::C::foo Invoke a method using its name foo This is foo: 42
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Scenario 1:
– Given a class C – Given an object o, instance of C – Identify all the methods available on o – Invoke a method using its name foo int main(void) { cse3009::C * o = new cse3009::C(42); std::cout << "Identify all the methods available on o" << std::endl; identify_members(o); std::cout << "Invoke a method using its name foo" << std::endl; invoke_member_function(o); return 0; }
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Scenario 1:
– Given a class C – Given an object o, instance of C – Identify all the methods available on o – Invoke a method using its name foo template<typename O> void identify_members(O * _o) { using namespace mirror; typedef MIRRORED_CLASS(O) meta_Class; std::cout << "\t(The type of o is " << meta_Class::full_name() << ")" << std::endl; std::cout << "\t"; mp::for_each_ii< all_member_variables<meta_Class> >(info_printer()); std::cout << std::endl << "\t"; mp::for_each_ii< member_functions<meta_Class> >(info_printer()); std::cout << std::endl; }
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Scenario 1:
– Given a class C – Given an object o, instance of C – Identify all the methods available on o – Invoke a method using its name foo template<typename O> void invoke_member_function(O * _o) { using namespace mirror; typedef MIRRORED_CLASS(cse3009::C) meta_Class; typedef mp::at_c<overloads< mp::at_c<member_functions<meta_Class>, 0>::type>, 0>::type meta_foo; my_invoker_maker::invoker<meta_foo>::type invoker( std::string("\tThis is foo: ")); invoker.call_on(*_o); }
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Mirror
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Scenario 1:
– Given a class C – Given an object o, instance of C – Identify all the methods available on o – Invoke a method using its name foo MIRROR_REG_BEGIN MIRROR_QREG_GLOBAL_SCOPE_NAMESPACE(std) MIRROR_REG_CLASS_BEGIN(struct, std, string) MIRROR_REG_CLASS_END MIRROR_QREG_GLOBAL_SCOPE_NAMESPACE(cse3009) MIRROR_REG_CLASS_BEGIN(class, cse3009, C) MIRROR_REG_CLASS_MEM_VARS_BEGIN MIRROR_REG_CLASS_MEM_VAR_GET_SET( private, _, int, i, _.get_i(), _.set_i(_i)) MIRROR_REG_CLASS_MEM_VARS_END MIRROR_REG_MEM_FUNCTIONS_BEGIN MIRROR_REG_MEM_OVLD_FUNC_BEGIN(foo) MIRROR_REG_MEM_FUNCTION_BEGIN(public, _, void, foo, 1) MIRROR_REG_MEM_FUNCTION_PARAM(std::string, _s) MIRROR_REG_MEM_FUNCTION_END(1, _) MIRROR_REG_MEM_OVLD_FUNC_END(foo) MIRROR_REG_MEM_FUNCTIONS_END MIRROR_REG_CLASS_END MIRROR_REG_END
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Scenario 1:
– Given a class C – Given an object o, instance of C – Identify all the methods available on o – Invoke a method using its name foo template<class Unused> struct my_manufacturer<std::string, Unused> { const std::string s; template<class ConstructionInfo> inline my_manufacturer(const std::string _s, const ConstructionInfo construction_info) : s(_s) { } void finish(std::string) const { } inline std::string operator()(void) const { return s; } }; typedef mirror::invoker_maker<my_manufacturer, mirror::default_fact_suppliers, my_enumerator, void> my_invoker_maker;
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Mirror
std_cpp_refl-latest.pdf
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Scenario 2:
namespace cse3009 { class C { private: int i; public: C(const int _i) : i(_i) { } int get_i(void) const { return this->i; } void set_i(const int _i) { this->i = _i; } void foo(const std::string _s) const { std::cout << _s << this->i << std::endl; } }; } – Given an object o, instance of C – Save on disk the complete state of o – Restore from disk the object o at a later time
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Scenario 2:
– Given an object o, instance of C – Save on disk the complete state of o – Restore from disk the object o at a later time Save on disk the complete state of o (The type of o is cse3009::C) cse3009::C::i = 42 Restore from disk the object o at a later time 43
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Scenario 2:
– Given an object o, instance of C – Save on disk the complete state of o – Restore from disk the object o at a later time int main(void) { cse3009::C * o = new cse3009::C(42); std::cout << "Save on disk the complete state of o" << std::endl; save_on_disk(o); std::cout << "Restore from disk the object o at a later time" << std::endl; restore_from_disk<cse3009::C>(); return 0; }
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Scenario 2:
– Given an object o, instance of C – Save on disk the complete state of o – Restore from disk the object o at a later time template<typename O> void save_on_disk(O * _o) { using namespace mirror; typedef MIRRORED_CLASS(O)meta_Class; std::cout << "\t(The type of o is " << meta_Class::full_name() << ")" << std::endl << "\t"; mp::for_each_ii<all_member_variables<meta_Class>>( info_printer_variables<O>(*_o)); std::cout << std::endl; }
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Scenario 2:
– Given an object o, instance of C – Save on disk the complete state of o – Restore from disk the object o at a later time template<class O> struct info_printer_variables { O o; inline info_printer_variables(O _o) : o(_o) { } template<class IterInfo> void operator()(IterInfo) { using namespace mirror; std::cout << IterInfo::type::full_name() << " = " << IterInfo::type::get(o); if (!IterInfo::is_last::value) std::cout << ", "; } };
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Scenario 2:
– Given an object o, instance of C – Save on disk the complete state of o – Restore from disk the object o at a later time template<typename O> void restore_from_disk(void) { using namespace mirror; typedef typename my_factory_maker::factory<O>::type my_factory_type; my_factory_type my_factory(43); O o(my_factory()); std::cout << "\t" << o.get_i() << std::endl; }
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Scenario 2:
– Given an object o, instance of C – Save on disk the complete state of o – Restore from disk the object o at a later time typedef mirror::factory_maker< my_manufacturer, mirror::default_fact_suppliers, my_enumerator, void> my_factory_maker;
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Scenario 2:
– Given an object o, instance of C – Save on disk the complete state of o – Restore from disk the object o at a later time template<class Unused> struct my_manufacturer<void, Unused> { template<typename Context> my_manufacturer(int _value, Context) { } void finish(int) { } template<class ConstructionInfo> inline int add_constructor( int _value, ConstructionInfo) const { return _value; } inline int index(void) { return 0; } };
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template<class Product, typename IsEnum> struct my_base_manufacturer { Product x; struct constr_param_name_printer { template<class IterInfo> inline void operator()(IterInfo) const { if (!IterInfo::is_first::value) std::cout << ", "; std::cout << IterInfo::type::base_name(); } }; struct constr_context_printer { template<class IterInfo> inline void operator()(IterInfo) const { if (!IterInfo::is_first::value) std::cout << "::"; std::cout << IterInfo::type::base_name(); } }; template<class ConstructionInfo> my_base_manufacturer(int tabs, ConstructionInfo construction_info, const Product& _x) : x(tabs) { } void finish(int) { } inline Product operator()(void) { return x; } }; template<class Product, class Unused> struct my_enumerator : my_base_manufacturer<Product, std::true_type> { template<class ConstructionInfo> inline my_enumerator(int tabs, ConstructionInfo construction_info) : my_base_manufacturer<Product, std::true_type>( tabs, construction_info, Product()) { } void finish(int) { } inline Product operator()(void) { return NULL; } }; template<class Product, class Unused> struct my_manufacturer { typedef typename mirror::factory_maker< my_manufacturer, mirror::default_fact_suppliers, my_enumerator, Unused> maker; typename maker::template factory<Product>::type f; template<class ConstructionInfo> inline my_manufacturer( int _value, ConstructionInfo construction_info) : f(construction_info) { } void finish(int) { } inline Product operator()(void) { return f(); } };
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Scenario 2:
– Given an object o, instance of C – Save on disk the complete state of o – Restore from disk the object o at a later time // make the input object for the factory script_factory_input in; // create a factory plugged with the script parser script_factory_maker::factory<tetrahedron>::type f = in.data(); // make a tetrahedron object factory soci_quick_factory_maker::factory<test::tetrahedron>::type tetrahedron_factory = soci_fact_data(r); while(r != e) { test::tetrahedron t = tetrahedron_factory(); // and write it to std output std::cout << stream::to_json::from(t, [&i](std::ostream& out) {
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Scenario 3:
namespace cse3009 { class C { private: int i; static int numberOfInstances; public: C(const int _i) : i(_i) { numberOfInstances++; } ... void foo(const std::string _s) const { std::cout << _s << this->i << std::endl; } static int getNumberOfInstances() { return numberOfInstances; } }; } – Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
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Scenario 3:
int cse3009::C::numberOfInstances = 0; int main(void) { cse3009::C * o1 = new cse3009::C(42); cse3009::C * o2 = new cse3009::C(1); cse3009::C * o3 = new cse3009::C(100); std::cout << o1 << std::endl << o2 << std::endl << o3 << std::endl; std::cout << cse3009::C::getNumberOfInstances() << std::endl; return 0; } – Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
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Scenario 3:
0x800418f8 0x80041908 0x80041918 3 – Given a class C – Record the numbers of its instance ever created – Report this number when the program ends
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Scenario 4:
http://www.stroustrup.com/wrapper.pdf
http://channel9.msdn.com/Shows/Going+Deep/ C-and-Beyond-2012-Herb-Sutter-Concurrency-and- Parallelism
http://www.codeproject.com/Articles/34237/A-C-Style-
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo()
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Scenario 4:
http://www.stroustrup.com/wrapper.pdf
http://channel9.msdn.com/Shows/Going+Deep/ C-and-Beyond-2012-Herb-Sutter-Concurrency-and- Parallelism
http://www.codeproject.com/Articles/34237/A-C-Style-
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo()
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo() Bjarne Stroustrup's Template: (Prefix::operator->()) This is o: 42
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo() int main(void) { std::cout << "Bjarne Stroustrup's Template:" << std::endl; cse3009::C o2(42); Prefix<cse3009::C> prefixed_o2(&o2); prefixed_o2->foo("This is o: "); std::cout << std::endl; return 0; }
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo() template<class T> class Prefix { T* p; public: Prefix(T * _p) : p(_p) { } T* operator->() { std::cout << "(Prefix::operator->())" << std::endl; return p; } };
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo()
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Scenario 4:
http://www.stroustrup.com/wrapper.pdf
http://channel9.msdn.com/Shows/Going+Deep/ C-and-Beyond-2012-Herb-Sutter-Concurrency-and- Parallelism
http://www.codeproject.com/Articles/34237/A-C-Style-
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo()
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo() Visual C++ 2013 06157-004-0441005-02428
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Scenario 4:
In file included from ..\Source\scenario4.cpp:32:0: ..\Source\../CPatcher/patcher.h: In instantiation of 'void CPatch::HookClassFunctions(T1&, T2, bool, bool) [with T1 = void (cse3009::C::*)(std::basic_string<char>); T2 = void (class_for_patches::*)(std::basic_string<char>)]': ..\Source\../CPatcher/patcher_defines.h:131:2: required from 'CPatch::CPatch(TReturnVal (TClassSource::*&)(TArg1), TReturnVal (TClassTarget::*)(TArg1), bool, bool) [with TClassSource = cse3009::C; TClassTarget = class_for_patches; TReturnVal = void; TArg1 = std::basic_string<char>]' ..\Source\scenario4.cpp:52:61: required from here
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo()
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Scenario 4:
between-void-and-a-pointer-to-member-function
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo() *reinterpret_cast<long*>(&fn_funcToHook) *reinterpret_cast<long*>(&fn_Hook)
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo() void(ptidej::C::*pfn_foo)(const std::string) = &ptidej::C::foo; class proxy { public: void my_foo(const std::string s) { std::cout << "Function foo() is patched!" << std::endl << std::flush; (reinterpret_cast<ptidej::C*>(this)->*pfn_foo)(s); } }; int _tmain(int argc, _TCHAR* argv[]) { CPatch patch_aclass_doSomething(pfn_foo, &proxy::my_foo); ptidej::C o(42);
return 0; }
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo() Function foo() is patched! This is o: 42
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Scenario 4:
– Given an object o, instance of C – Without changing o or C – Change the behaviour of o.foo()
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Scenario 1: invoke an arbitrary method on an object (see
the problems with instanceof and plugins)
Scenario 2: access the complete (including private) state of
an object (see the problem with serialisation)
Scenario 3: count the number of instances of a class
created at runtime (see the problem with debugging/profiling)
Scenario 4: modify the behaviour at run-time of a method
without the need to recompile and restart the program (see the problem with patching)
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Reflection helps addressing these scenarios
Use reflection sparingly and purposefully
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1.
Introduction
2.
Bibliothèques et cadriciels
– Types d’interconnexions – Problèmes légaux – Chargement dynamique
3.
Réflexion
4.
Théorie
– Méta-classes – Protocoles de méta-objets (MOP) – MOP à la compilation, à l’exécution
5.
Retour sur le chargement dynamique
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Class
Metaclass
Aristote (Ἀριστοτέλης) *-384 †-322
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An object is an instance of a class
A class is an instance of a metaclass
A metaclass is an instance of…
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An object is an instance of a class
A class is an instance of a metaclass
A metaclass is an instance of…
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The class Object is the parent of all
The class Class is the generator of all
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Des langages de programmation à objets à la représentation des connaissances à travers le MOP : vers une intégration par Gabriel Pavillet. Thèse de doctorat en Informatique sous la direction de Roland Ducournau, soutenue en 2000 à Montpellier 2
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The classes
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Java
Field
∈ C
Method ∈ C Static field ∈ C Static method ∈ C
Instance variable
∈ C
Instance method
∈ C
Class variable
∈ C class
Class method
∈ C class
Class instance variables
– To count the numbers of instances of subclasses of C (D, E…) independently from
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1.
Introduction
2.
Bibliothèques et cadriciels
– Types d’interconnexions – Problèmes légaux – Chargement dynamique
3.
Réflexion
4.
Théorie
– Méta-classes – Protocoles de méta-objets (MOP) – MOP à la compilation, à l’exécution
5.
Retour sur le chargement dynamique
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Earlier, we said that reflection is of
Brian Cantwell Smith “Procedural Reflection in Programming Languages” (Ph.D. thesis, 1982)
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Earlier, we said that reflection is of
Brian Cantwell Smith “Procedural Reflection in Programming Languages” (Ph.D. thesis, 1982)
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Earlier, we said that reflection is of
Brian Cantwell Smith “Procedural Reflection in Programming Languages” (Ph.D. thesis, 1982)
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In Java, the metaclass is anonymous and
In Smalltalk, “[t]here is only one instance of a
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Many other variations are possible
– LISP
– Perl 5, 6
– Python
– MetaclassTalk – Noury Bouraqadi, Pierre Cointe
– NeoClassTalk – Fred Rivard, Pierre Cointe
– OpenC++ – Shigeru Chiba, Gregor Kiczales
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A Meta Object Protocol exposes some or all
The MOP is (often) a set of classes and
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MOP can be accessible at
– http://www.csg.ci.i.u-tokyo.ac.jp/openjava/
– http://www.csg.ci.i.u-tokyo.ac.jp/~chiba/javassist/
– http://eclipse.org/aspectj/
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1.
Introduction
2.
Bibliothèques et cadriciels
– Types d’interconnexions – Problèmes légaux – Chargement dynamique
3.
Réflexion
4.
Théorie
– Méta-classes – Protocoles de méta-objets (MOP) – MOP à la compilation, à l’exécution
5.
Retour sur le chargement dynamique
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Virtual machines
Must
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Virtual machines
Must
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Virtual machines
Must
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Example
<pckg1>.….<pckgn>.<ClassName>
– net.ptidej.reflection.java.scenario1.C
final Class<ICommand> command = this.classLoader.loadClass(binaryName);
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http://map.sdsu.edu/geog583/images/week8.3.gif
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http://www.onjava.com/2005/01/26/graphics/Figure01_MultipleClassLoaders.JPG
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public class ClassLoader extends java.lang.ClassLoader { private final String directory; public ClassLoader( final java.lang.ClassLoader parent, final String directory) { super(parent); this.directory = directory; }
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protected Class findClass(final String name) { Class newClass = null; try { newClass = super.findClass(name); } catch (final ClassNotFoundException cnfe) { final String osName = this.directory + name.replace('.', '/') + ".class"; try { final FileInputStream fis = new FileInputStream(osName); newClass = this.defineClasses(name, fis); } catch (final ClassFormatError cfe) { cfe.printStackTrace(Output.getInstance().errorOutput()); } catch (final FileNotFoundException fnfe) { // fnfe.printStackTrace(); } } return newClass; }
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private Class defineClasses(final String name, final InputStream inputStream) { try { int b; int length = 0; byte[] bytes = new byte[4]; while ((b = inputStream.read()) != -1) { if (length == bytes.length) { final byte[] temp = new byte[length + 4]; System.arraycopy(bytes, 0, temp, 0, length); bytes = temp; } bytes[length] = (byte) b; length++; } System.out.println(name); final Class newClass = this.defineClass(name, bytes, 0, length); return newClass; } catch (final IOException ioe) { return null; } catch (final NoClassDefFoundError ncdfe) { ncdfe.printStackTrace(Output.getInstance().errorOutput()); return null; } }
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http://www.onjava.com/2005/01/26/graphics/Figure01_MultipleClassLoaders.JPG
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protected Class findClass(final String name) { Class newClass = null; try { newClass = this.getParent().loadClass(name); } catch (final ClassNotFoundException cnfe) { final String osName = this.directory + name.replace('.', '/') + ".class"; try { final FileInputStream fis = new FileInputStream(osName); newClass = this.defineClasses(name, fis); } catch (final ClassFormatError cfe) { cfe.printStackTrace(Output.getInstance().errorOutput()); } catch (final FileNotFoundException fnfe) { // fnfe.printStackTrace(); } } return newClass; }
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Virtual machines must access resources and