Education for a Digital World Advice, Guidelines and Effective Practice from Around Globe, 2008a

19 – Building Communities of Practice
effective sharing of information between groups, SOA
can help define the relationship between the user and
the software application. 59
Flexibility, rapid development, and good scalability
can be encouraged with the adoption of: a common notation
(UML), and a defined data model (XML). In its
most basic form, SOA is a technique for component
software reuse (FastSOA, p. 84). The SOA design pattern
is well suited to update data aggregation services
and perform complex federated service requests (Fast
SOA, p. 65). This task is not easily achieved in more
structured languages such as SQL.
Simple object access protocol
Mid-tier processing is used to address the difficulties
that arise when flexible XML technology is merged with
a relational database management system (RDBMS).
Common techniques for mapping data from XML files
to database storage systems use the simple object access
protocol (SOAP), which “allows us to pass structured,
typed data in a decentralized, distributed environment”
(Lecky-Thompson et al., 2005).
The SOAP—remote procedure call (RPC) uses exponentiated
encoding to map XML data structures to
data objects located within trusted memory resources
allocated to programming languages. As a result,
“SOAP-RPC bindings instantiate up to 15,000 Java objects
to deserialize the SOAP request that contain 500
elements in the SOAP message body.” (Perkins et al., p.
274).
The complex auto-binding ability that maps XML
content to database storage (XML-RPC) should be used
sparingly as files over 96kbs can have a dramatic impact
on CPU and network bandwidth (FastSOA, p. 69). Alternatively,
XML documents can be encoded literally,
using SOAP-document-literal-encoding. SOAP-documentliteral-encoding,
however, does not allow you finegrained
control over the data source from Java.
Java and the Enterprise Java Bean
EJB stands for “Enterprise JavaBeans” which are
distributed network-aware components for developing
secure, scalable, transactional and multiuser
components in a J2EE environment. (Sun Microsystems,
2007)
59
This relationship between the user interface and software
application is defined by Bieberstein et al., as the Human
Service Bus; an optimized organizational structure designed
to meet the needs of the on-demand business environment
(p. 698).
Java and PHP are both programming languages. Languages
have advantages over document parsers when
supplying complex mathematical and functional routine
libraries. These libraries send requests for computer
processing resources. For Java languages, this request is
created within a Java container. The container often
used for Java server page content is Project Catalina
(Tomcat). Tomcat runs these libraries by establishing a
trusted set of memory resources on the computer platform.
Trust is established within Java by using defined
functional components as described by the Technology
compatibility kits (TCK) developed through the Java
community process (Dmitry A. Fazunenko, JDJ, p. 26).
These technology compatibility kits (TCK) are distributed
using the XML data model. TCKs ensure that vital
information is distributed for the conformance testing
of components such as the Enterprise JavaBeans (EJB),
and are available upon subscription from Sun Microsystems.
The trusted memory resources restrict Java from accessing
external resources. EJBs provide access to those
restricted resources. This access is secured through
highly defined relationships that coordinate and facilitate
the transmission of information between the programming
language and networking infrastructure. In
other words, Enterprise JavaBeans can be described as a
set of components that help to define a collection of
properties (classes) and access points (interfaces) used to
enhance interaction between the system and user.
LearningTimes, a web application, is one such example
of a Java based community application. This application
is built on open source (CommunityZero)
technology and uses highly structured database technology
distributed across multiple servers and multiple
locations to offer secure, scalable, and reliable services.
XML document parsers
Data can be referenced, recorded, and organized using
less complex and more flexible tools available in native-
XML document parsers such as the document object
model (DOM), streaming API for XML (StAX), or Java
architecture for XML Binding (JAXB) to name just a
few. XML document parsers work alongside your webserver
(Apache, IIS, Lighttpd [Lighty], Cherokee) to
organize data using arithmetic operators (addition/subtraction
and multiplication/division) without
the processor-intensive mathematical libraries available
to Java, Perl, Ruby, or Python.
Although a detailed explanation of document parsers
is beyond the scope of this chapter, the above document
parsers provide access to objects from within program-
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