Presentation 8: SOAP in a distributed object framework, Application Servers & AXIS SOAP

Ingeniørhøjskolen i Århus Slide 2 af 14 Outline SOAP and Web Services in relation to Distributed Objects The AXIS Project – Open Source Java SOAP Server –Introduction to the Apache Tomcat Application Server –Introduction to the AXIS Project –How to install

SOAP & Web Services in relation to Distributed Objects

Ingeniørhøjskolen i Århus Slide 4 af 14 SOAP and Distributed Objects SOAP in it self has nothing to do with objects There probably is SOAP API’s for C and COBOL The trick is the supporting API’s converting objects to WSDL and SOAP for serialization across the network Using the Proxy Pattern for decoupling – perhaps with the Façade Pattern for larger granularity –Emmerich: Accessing distributed objects is expensive –Use larger granularity More on Architecture later in the course

Ingeniørhøjskolen i Århus Slide 5 af 14 Proxy Pattern (GoF version) Watch Client RealWatch ProxyWatchTestWatch setTime() Objects of RealWatch class are locateed on a different machine than the Client object. This is an example of Remote Proxy – which is an Architectural Pattern. from GoF abstract GoF: Gang Of Four (Design Pattern bog af Gamma m.fl.)

Ingeniørhøjskolen i Århus Slide 6 af 14 Proxy Pattern (B. Douglas version) Client Object SOAP Proxy Server object BD.s212 Client component Server component Proxy Pattern Client Server Proxy Proxy (= en stedfortræder) By encapsulating The SOAP communication in a Proxy, we have decoupled the Client Object from needing to know that it calls over The Internet. Thus making it easy to implement different Middleware and use the Server object locally We could do the same for The Server object

Ingeniørhøjskolen i Århus Slide 7 af 14 Façade Pattern (also GoF) Used for encapsulation and decoupling The entire Client Subsystem is decoupled from the server and a Client Proxy hides the SOAP implementation (also Server Proxy) This is known as Client Stubs & Server Skeletons The entire Client Subsystem is decoupled from the server and a Client Proxy hides the SOAP implementation (also Server Proxy) This is known as Client Stubs & Server Skeletons

Frameworks for Webservices & The AXIS Project – Open Source Java SOAP Server

Ingeniørhøjskolen i Århus Slide 9 af 14 How to make a Webservice with SOAP You need an application or API capable of supporting: –Communication over the Internet (HTTP) –Security (SSL) –XML Parsing capabilities –… Two examples of this: –Apache Tomcat Application Server with AXIS –Microsoft Internet Information Server We will use them both – though starting with the Apache Tomcat Application Server and the AXIS project – this will be introduced here

Ingeniørhøjskolen i Århus Slide 10 af 14 Apache Tomcat Application Server Apache Project is a open source project – widely supported by Sun & IBM (but not Microsoft) –Including a huge amount of free coding effort from both It consist of a long range of projects including: –Apache Web Server The most used web server in the world (and its free!) The most secure, with SSL cap., and NT, Linux & UNIX support Huge amount of ”plug-in” modules One of theese being the Apache Tomcat AS –Apache Tomcat Application Server Capable of running JAVA applications JSP/Servlets And projects embedded into this – –The AXIS Project The former Apache SOAP Server Runs embedded in Tomcat

Ingeniørhøjskolen i Århus Slide 11 af 14 Apache Tomcat AS Works on: –Windows, UNIX, LINUX, Mac –Can be compiled to any platform (with some work) Can be found at: – Server listening for events: –HTTP on port 8080 (optionel) –Executes Servlets/JSP and JAVA applications –AXIS is an embedded project within the Tomcat environment SOAP Client Java, C++, C#, Delphi, VB Application SOAP Client Java, C++, C#, Delphi, VB Application SOAP over HTTP Web Server Apache / MS IIS Web Server Apache / MS IIS AS/SOAP Server (Tomcat with AXIS) AS/SOAP Server (Tomcat with AXIS) JSP/ Servlet JSP/ Servlet Web Service Web Service Object Common code base!

Ingeniørhøjskolen i Århus Slide 12 af 14 AXIS Project Provides us with a suitable framework Runs embedded in Apache Tomcat – just download – But can run on ANY Application Server –BEA, WebSphere, Supports full WSDL Supports SOAP communication via: –HTTP, SMTP, FTP and open for extension Build in security, log, error and fault handling (some are still “under construction”) Tools for WSDL Stub & Skeleton creation: –WSDL2Java & –Java2WSDL Flexible deployment system

The AXIS Project – How to Install

Ingeniørhøjskolen i Århus Slide 14 af 14 How to Install We do not need the Apache Web Server –As Tomcat has its own HTTP capabilities Start with Apache Tomcat Application Server – Test installation is OK Then Install the AXIS Project – I have prepared a brief installation help document to be found at the course web site