Extreme Java G22.3033-006 Session 1 – Main Theme Introducing Extreme Java Dr. Jean-Claude Franchitti New York University Computer Science Department Courant Institute of Mathematical Sciences Agenda • Course Logistics, Structure and Objectives • Java Programming Language Features • Java Environment Limitations • Upcoming Features in “Tiger” 1.5 • Model Driven Architectures for Java Systems • Java Enterprise Application Enabling • Agile Modeling & eXtreme Programming • Aspect-Oriented Programming & Refactoring • Java Application Performance Enhancement • Readings, Class Project, and Assignment #1a 2 1 Course Logistics • Course Web Site • http://cs.nyu.edu/courses/spring03/G22.3033-006/index.htm • http://www.nyu.edu/classes/jcf/g22.3033-007/ • (Password: extjava) • Course Structure, Objectives, and References • See detailed syllabus on the course Web site under handouts • See ordered list of references on the course Web site • Textbooks • Mastering Java 2, J2SE 1.4 • J2EE: The Complete Reference • Expert One-on-One: J2EE Design and Development 3 Part I Java Features 4 2 Java Features Review • Language Categories • Imperative • Functional • Logic-based • Model-based PL Comparison Framework • Data Model • Behavioral Model • Event Model • Execution, Persistence, etc. • See Session 1 Handout on Java Review 5 J2SE 1.4 Features http://java.sun.com/j2se/1.4/index.html 6 3 J2SE 1.4 Features (continued) • HotSpot virtual machine • Full 64-bit support • Improved garbage collection • Ability to exploit multiprocessing • Optimization of the Java2D API • Classes/API Enhancements and Additions • Internationalization (Unicode 3.0) • JDBC SPI to J2EE Connector architecture • Java.nio, java.util.regex, assertions, JAXP, java.util.properties, java.util.logging • J2SE 1.4.1 Enhancements • http://java.sun.com/j2se/1.4.1/changes.html 7 Java Environment Limitations • No Support for Behavioral Reflection (BR) • Reification is the inverse of reflection (e.g., class loader) • Structural reflection reifies structural aspects of a program (inheritance/data type) • Behavioral reflection reifies computation and their behavior • http://www4.informatik.uni-erlangen.de/Projects/PM/Java/ (JX) • http://www4.informatik.uni-erlangen.de/TR/pdf/TR-I4-97-10.pdf • http://www.dcc.unicamp.br/~oliva/guarana/ • Limited Execution State Control • Hard to implement agent-based systems (e.g., IBM’s agglets project) • Limited Performance • See later slides •etc. 8 4 The JX Operating System http://www4.informatik.uni-erlangen.de/Projects/JX/ 9 New Features in “Tiger” 1.5 http://www.jcp.org/en/jsr/detail?id=176 • Mantis 1.4.2 • Bug fixes and performance improvements •Tiger 1.5 • Generics, similar to templates in C++ • Autoboxing of primitives • Addresses some of the problems with casting • When value types need to be treated as objects, the JVM wraps them within a heap-allocated reference type using a process called boxing • Better support for constants • Programming shortcuts using import statements • Improvements for iterating over collections • Metadata either as a keyword addition or a javadoc feature 10 5 “Tiger” 1.5 Generics http://www.jcp.org/en/jsr/detail?id=176 • Generics feels like C++ Templates++: • Compile time checking • Apply on everything from classes to methods • Support constraints on generic arguments using a where clause •Example • interface IComparable<T> { int CompareTo(T obj); } class Dictionary<K, V>: IDictionary<K, V> where K: IComparable<K>, V: IKeyProvider<K>, V: IPersistable, V: new() { ... } 11 Part II Software Architectures Engineering and Java Enterprise Application Enabling 12 6 Enterprise Software Foundations • Enterprise Architecture Model • Business Architecture • Application Architecture • Technical Architecture • Object-Oriented Software Development • Iterative/Incremental Development Process • OO Concepts (modularity, encapsulation, abstraction, reuse) • Component-Based Software Development • Process paired with OO Development • Canned component models 13 Enterprise Architectures Enablers • User Interfacing • XHTML, XML, AWT, Swing, thinlets, etc. • Distributed Communications Enabling • TCP/IP, Java IDL, CORBA, RMI/IIOP, DCOM, etc. • Services for Distributed Communications • JNDI, CORBA Trading, JINI, JAF, JMS, JavaMail, JTA/JTS, JAAS/JCE/JSSE, etc. • Data Enabling • JDBC, SQLJ, EJB-QL, CMP/BMP, etc. • Systems Assurance • Security, Reliability, Availability, Maintainability, Safety • Web Enabling • Java Web Start, Servlets, JSP, XSP, etc. • Application Enabling • Web Services, EJB, EAI/B2Bi, JCA, JMX, Java XML Pack, JAXB, etc. 14 7 Software Development Infrastructure • OO Development •UML • OOPLs (Java, C++, C#, Jython, etc.) • Component-Based Development • UML (patterns, frameworks), MOF, XMI • Web Services, Java Web Start, JavaBeans, CORBA, RMI/IIOP, DCOM, Java APIs (J2SE foundation classes), J2EE (Servlets, JSPs, EJBs), CORBAcomponents, Microsoft COM+/DNA/.Net, etc. • JPDA (Java Platform Debugger Architecture) 15 Distributed Communications Enabling Underlying Protocols •TCP/IP • Web/HTTP, SSL • XMLP, SOAP • CORBA/IIOP, GIOP, HTTP-NG •RMI/JRMP • RMI/IIOP •DCOM 16 8 Distributed Communications Enabling Core Common Services • Naming • DNS, JNDI • Directory • NIS, NDS, LDAP, Microsoft Active Directory • Trading • CORBA Trading Service, JINI • Activation • CORBA LifeCycle Service, Java Activation Framework • Messaging • JMS, JavaMail, CORBA Events/Messaging/Notification • Transaction • CORBA OTS, JTS, JTA • Security • JSSE, JCE, JAAS 17 Sample Enterprise Application Design • See Sub-Topic 1 Presentation: • Best Practices in Technical Architectures for Fixed Income Market Participants 18 9 The first level of automation ~ 30 Years (Platform independent to platform specific model projection) Programming IDEs (e.g. JBuilder, Visual Age, NetBeans) Environment •Higher level of expression PIM Programming Language •Easier to understand •Portable •Standardized •Dependable Generator, •Flexible Projection Compiler Engine •Configurable •Optimizing •Complete: Linker, Debugger, Etc. PSM Diverse HW/OS Platforms 19 MDA= New automation levels ~ Last 8 Years http://www.omg.org/mda Architectural IDEs Environment •Higher level of expression PIM Model (UML, BOM…) & •Easier to Modeling Style (J2EE, eEPC, COBOL, .NET…) understand •Portable •Standardized •Dependable Generator, •Flexible Generator Engine Projection •Configurable •Debuggable •Optimizing Models to Code •Complete Models to Models P-Stack: A Level of Automation PSM 20 10 Architectural IDEs http://www.io-software.com, The Unified Process Std. MDA Projections ArcStyler Core Modules J2EE/EJB, .NET BEA WebLogic Open MDA/UML/XML Repository MDA Cartridges Business Pattern UML MDA-Engine Build, IBM WAS NT, z/OS Object Refinement Refinement Engine Deploy & Test with Meta IDE Modeler Assistant Assistant Support Borland, JBoss Optional integrated Tools IDS ARIS Rational Rose Programming IDE Oracle, IONA Architect MDA-Cartridge IDE & MDA Engine Edition adds support for custom infrastructure 21 Part III Mainstream Modeling and Programming Techniques http://www.agilemodeling.com/essays/agileModelingXP.htm 22 11 eXtreme Programming (XP) http://www.extremeprogramming.org/ • A lightweight software methodology • Few rules and practices or ones which are easy to follow • Emphasizes customer involvement and promotes team work • See XP’s rules and practices at http://www.extremeprogramming.org/rules.html 23 eXtreme Programming Project 24 12 XP Project Lifecycle 25 Agile Modeling & XP http://www.agilemodeling.com/, http://www.agilemodeling.com/resources.htm • Practices-based software process whose scope is to describe how to model and document in an effective and “agile” manner • One goal is to address the issue of how to apply modeling techniques on software projects taking an agile approach such as: • eXtreme Programming (XP) • Dynamic Systems Development Method (DSDM) • SCRUM •etc. • Using modeling throughout the XP lifecycle • http://www.agilemodeling.com/essays/agileModelingXPLifecycle.htm 26 13 Aspect-Oriented Programming http://www2.parc.com/csl/projects/aop • Technology for separation of concerns (SOC) in software development • AOSD makes it possible to modularize crosscutting aspects of a system such as • Design or architectural constraints • Systemic properties or behaviors (e.g., logging and error recovery) • Features •etc. 27 AspectJ http://aspectj.org • A seamless aspect-oriented extension to Java • Enables the modular implementation of a wide range of crosscutting concerns • Compilers • AspectJ (www.aspectj.org) • HyperJ (www.alphaworks.ibm.com/tech/hyperj) 28 14 AspectJ Example http://www.voelter.de/data/articles/aop/aop.html 01 aspect DataLog { 02 advise * Worker.performActionA(..), * Worker.performActionB(..) { 03 static after { 04 if ( thisResult == true ) 05 System.out.println( "Executed "+thisMethodName+ 06 "successfully!" ); 07 else 08 System.out.println( "Error Executing "+ 09 thisMethodName ); 10 } 11 } 12 } 29 Refactoring http://www.refactoring.com/ • Technique to restructure code in a disciplined way • Small code changes (a.k.a., refactorings) are applied to support new requirements and/or keep design as simple as possible • Enables programmers to safely and easily evolve their code to fulfill new requirements or improve its quality • Refactoring is a fundamental coding practice of XP and is orthogonal to Agile Modeling, which does not address programming-related issues • See Java refactoring guidelines at • http://www.cafeaulait.org/slides/javapolis/refactoring/ • Refactoring tools: • Eclipse