![Bytecode Transformer
public class JPAClassTransformer implements ClassFileTransformer {
public byte[] transform(ClassLoader loader, String className,
Class<?> clazz, ProtectionDomain domain,
byte[] classfileBuffer) throws IllegalClassFormatException {
...
}
}](https://image.slidesharecdn.com/jpatheversantway-121021135921-phpapp02/85/JPA-the-Versant-Way-18-320.jpg)
![Abfangen von Zugriffen
public class FieldInterceptorsClassVisitor extends ClassVisitor {
public MethodVisitor visitMethod(int access, String name,
String desc, String signature, String[] exceptions) {
...
MethodVisitor mv = super.visitMethod(access, name, desc,
signature, exceptions);
return new FieldInterceptorMethodVisitor(mv, ...);
}
...
}](https://image.slidesharecdn.com/jpatheversantway-121021135921-phpapp02/85/JPA-the-Versant-Way-21-320.jpg)
JPA the Versant Way
- 1. JPA the Versant Way Jürgen Becker Viktor Dreiling
- 2. Agenda 1. Versant 2. Big Data 3. Versant JPA 4. Java-Agent und Bytecode-Manipulation 5. Versant JPA Analytics Platform 6. Ingestion / Analytics Demo
- 3. Versant
- 4. Das Unternehmen ● Fokus auf Objektdatenbanken ○ Datenbanken: VOD, DB4O, FastObjects ○ Schnittstellen: proprietär, JDO ● Kunden ○ Verizon, Samsung, Ericsson, British Airways ○ ...
- 5. Big Data
- 6. Ziele ● Große, komplexe Datenmengen ○ Speicherung (Skalierbarkeit) ○ Analyse (Tools) ○ Zugriff (Standards)
- 7. Architektur
- 8. Architektur Versant DB
- 9. Architektur Versant DB
- 10. Architektur Versant JPA Analytics Platform Versant JPA (Client + Server) Versant JPA Server
- 11. Versant JPA
- 12. Versant JPA ● Client + Server ○ Storage: Objektdatenbank ○ Subset des JPA Standards 2.0 ■ Kein ORM ■ Anwendungsmodell = Datenbankmodell ○ Herstellerspezifische Erweiterungen ■ Generic API, Indizes, Server Administration API ○ Fokus: Performance und einfache Benutzbarkeit
- 14. Speichern einer Entity ? Entity DB
- 15. Beispiel Entity @Entity public class Attendee { @Id private long id; private String firstName; public String getFirstName() { return this.firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } }
- 16. Entity Attribute ● JPA Spec: Feld muss mit private, protected oder package visibility deklariert werden ● Zugriff über getter / setter Methoden - JavaBean ● @Access(FIELD) oder @Access(PROPERTY)
- 17. Entity Zustand ● Reflection / Dynamic Proxies ☹☹☹ ● Bytecode-Manipulation ☺☺☺ ○ Build-time ○ Run-time mit einem Agenten
- 18. Bytecode Transformer public class JPAClassTransformer implements ClassFileTransformer { public byte[] transform(ClassLoader loader, String className, Class<?> clazz, ProtectionDomain domain, byte[] classfileBuffer) throws IllegalClassFormatException { ... } }
- 19. Java-Agent trifft Transformer ● MANIFEST.MF Premain-Class: com.versant.Agent ● public class Agent { public static void premain(String args, Instrumentation inst) { inst.addTransformer(new JPAClassTransformer(args)); } } ● java -javaagent:<path>/versantjpa-agent.jar:<args>
- 20. Bytecode-Manipulation ● ASM 4.0 Framework (http://asm.ow2.org/) ● Manipulation und Analyse ● Schnell und Stabil ☺☺☺ ● 2 APIs ○ Event / Visitor basiert ~ SAX Parser ○ Objekt basiert ~ DOM
- 21. Abfangen von Zugriffen public class FieldInterceptorsClassVisitor extends ClassVisitor { public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) { ... MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions); return new FieldInterceptorMethodVisitor(mv, ...); } ... }
- 22. Abfangen von Zugriffen (cont) public class FieldInterceptorMethodVisitor extends MethodVisitor { public void visitFieldInsn(int opcode,String owner,String name,String desc) { ... switch (opcode) { ... case Opcodes.PUTFIELD: super.visitMethodInsn(INVOKESTATIC, declaringClassName, "_vjpaInterceptWrite_" + name, methodTypeDescriptor); return; } } }
- 23. Original Bytecode public class Attendee extends Object { ... private String firstName; public void setFirstName(String); Code: 0: aload_0 1: aload_1 2: putfield #2; //Field firstName:String; 5: return ...
- 24. Enhanced Bytecode public class Attendee extends Object { ... private String firstName; protected StateManager _vjpaStateManager; public void setFirstName(String); Code: 0: aload_0 1: aload_1 2: invokestatic #44; //Method _vjpaInterceptWrite_firstName:(SimpleEntity; String;)V 5: return
- 25. Enhanced Bytecode (cont) public static void _vjpaInterceptWrite_firstName(SimpleEntity, String); Code: ... 30: invokeinterface #63, 2; //InterfaceMethod StateManager.markDirty:(I)V 35: aload_0 36: aload_1 37: putfield #52; //Field firstName:String; 40: return
- 26. Agent + Bytecode-Manipulation ● Performance ○ JIT Optimierung möglich ● Anwendungsmöglichkeiten ○ Dynamic logging ○ Method Tracing ○ Class Generierung beim Testen ○ ...
- 27. Versant JPA Analytics Platform (TP)
- 29. Ingestion / R Demo
- 31. Danke ● Fragen ? ● Kontakt ○ vdreiling@versant.com ○ jbecker@versant.com ● http://community.versant.com/Forums.aspx
- 32. Wir suchen Verstärkung ! Lust auf Analytics / Data Mining, Verteilte Anwendungen, Datenbank Systeme ? Sehr gut in Java und/oder C/C++ ? jobs@versant.com