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1.3 Oracle Application Server Components

Up
to this point, we've introduced a lot of features
available in different versions of Oracle Application Server without
providing much explanation of what they do. The following subsections
group the main components of Oracle Application Server into three
basic categoriescore components, application components, and
additional componentsand describe briefly what these
components do.

Remember that this chapter includes only summary descriptions of the components that make up Oracle Application Server. Subsequent chapters will describe these components in greater detail.

1.3.1 Core Components

The components that make up the core of Oracle Application Server are
the Oracle HTTP Server, Oracle Application Server Containers for
J2EE, and OracleAS Web Cache.

1.3.1.1 Oracle HTTP Server

The Oracle HTTP Server, which is based on the
Apache Web Server, provides the services needed to handle incoming
HTTP requests and can serve as a proxy server. Developers can program
in languages such as Perl, C, C++, PL/SQL, and Java, and can leverage
libraries and frameworks such as BC4J, the XML
Developer's Kit, Java Naming and Directory Interface
(JNDI), and JDBC. The Oracle HTTP Server supports

Server Side Includes for adding
content (such as header or footer information) across all of a web
site's pages. Servers can be clustered in
high-availability configurations, and Oracle HTTP Server also
supports load balancing, which can couple high availability with
scalability. Security support includes OracleAS Single Sign-On and
encryption with the Chapter 5 describes the Oracle HTTP Server in
greater detail.

1.3.1.2 Oracle Application Server Containers for J2EE

Oracle
Application Server Containers for J2EE (OC4J) is a set of
J2EE-certified containers executed using any standard Java Virtual
Machine (JVM). OC4J provides a JSP translator, a servlet engine, and
an EJB container. It also provides other J2EE services to the
containers, such as JNDI, JDBC, Java Message Service (JMS), Java
Authentication and Authorization Service (JAAS), and Java Transaction
API (JTA). OC4J supports clustering, load balancing, and application
state replication for web and EJB applications, thus enabling highly
available and scalable configurations. OC4J can use Java Object Cache
in the OC4J containers.

Chapter 6 describes OC4J in greater detail.

1.3.1.3 OracleAS Web Cache

OracleAS Web Cache is a memory cache that
speeds the delivery of content to requesters. OracleAS Web Cache can
store both static and dynamic pages, as well as parts of pages that
are marked with Edge Side Include (ESI) tags. This cache
also provides other types of functionality, such as balancing request
loads between multiple instances of the Oracle HTTP Server and
monitoring the speed at which content is returned to users.

Chapter 7 describes OracleAS Web Cache, as well
as the other Oracle Application Server caches (Java Object Cache and
Web Object Cache), in greater detail.

1.3.2 Application Components

The components
of Oracle Application Server described in the following subsections
provide capabilities that can create and deploy applications.

1.3.2.1 Web Services

Web Services are
extensively supported in Oracle Application Server. The product
includes support for the following:

Java classes (either stateful or stateless) as
remote procedure call (RPC) or
document-style Web Services

Stateless EJBs as Web Services

PL/SQL stored procedures as Web
Services

JMS topics and queues as
document-style Web Services

Clients can invoke these either dynamically or statically.

Other standards supported include publishing and query with
UDDI and typed and untyped
SOAP messages with SOAP header
access via an application programming interface (API). A dynamic
WSDL tester allows you to create web-based
clients and simplify the testing of Web Services during development.

Chapter 11 describes Oracle Application Server
Web Services in greater detail.

1.3.2.2 Oracle Application Server TopLink

OracleAS TopLink is an object-relational
persistence tool used to store
Java objects and EJBs in
relational database tables. The visual mapping interface allows
developers to define how Java classes are mapped to database schema.
Thus, a Java developer using OracleAS TopLink
doesn't need to write SQL calls. Using the visual
mapping tool, the developer can usually handle database schema
changes without needing to recode the Java applications. The mapping
tool provides graphical views of relationships, queries, locking,
caching, sequencing, and other areas of interest that enable
performance tuning.

Chapter 8 describes OracleAS TopLink in greater
detail.

1.3.2.3 Oracle JDeveloper

Oracle
JDeveloper is a part of Oracle Developer Suite, rather than of Oracle
Application Server itself, but it can create the Java applications
that are deployed on an Oracle Application Server platform. Oracle
JDeveloper was introduced by Oracle in 1998 to enable the development
of basic Java applications without the need to write large amounts of
code. At the core of Oracle JDeveloper is an advanced application
development framework. Oracle JDeveloper provides numerous wizards
that create Java and J2EE objects and project types. Some wizards in
Oracle JDeveloper include:

A Data Form wizard

A Beans wizard for creating Java Beans
and BeanInfo classes

A Deployment wizard providing
"one-click" deployment of
J2EE applications to OC4J

Database development features include various Oracle drivers, a
Connection Editor to hide the complexity of using the JDBC API to
establish connections, database components to bind visual controls,
and a SQLJ precompiler for embedding
SQL in Java
code (which you can then
use with the Oracle database).

Oracle Application Server comes with a limited-use license for Oracle
JDeveloper. The development tool is packaged in the Oracle Developer
Suite.

Chapter 8 describes Oracle JDeveloper in
greater detail.

1.3.2.4 OracleAS Forms Services

Oracle Application Server Forms
Services provide data handling, navigation, database access, and
database validation for Oracle Forms applications. These services
allow Oracle Forms to run in an N-tier web
environment.

Forms deployed to Oracle Application Server are developed using the
Oracle Forms Developer, an
interactive development tool that is part of the Oracle Developer
Suite. Oracle Developer allows you to define applications by defining
values for properties, rather than by writing procedural code. Oracle
Developer supports a variety of clients, including traditional
client-server PCs and Java-based clients. The Forms Builder includes
a built-in JVM for previewing web applications.

Chapter 9 describes Oracle Application Server
Forms Services in greater detail.

1.3.2.5 OracleAS Reports Services

Oracle Application Server Reports Services enable the rapid
deployment and publishing of web-based reports. Reports can also
leverage the Oracle Application Server Single Sign-On capabilities
and can be embedded as portlets in OracleAS Portal.

Reports are created using the Oracle Reports Developer, a part of the
Oracle Developer Suite. Data can be
formatted in tables, matrixes, group reports, graphs, and
combinations. You can achieve high-quality presentation using

Cascading Style Sheets (CSS), an
HTML extension. Using OracleAS Reports Services,
XML-based reports can be
exchanged via HTTP, and paper-based layouts can be deployed over the
Internet using Chapter 9 describes Oracle Application Server
Reports Services in greater detail, and Chapter 12 describes Reports deployed for business
intelligence.

1.3.3 Additional Components

The components described in the
following subsections provide extended functionality that is an
important part of Oracle Application Server. These components relate
to specific areas of IT, such as business intelligence and
integration, or provide capabilities that can be used by developers,
such as OracleAS Portal or the Oracle Internet Directory.

1.3.3.1 OracleAS Portal

OracleAS Portal, packaged with Oracle Application
Server, provides an HTML-based tool for developing web-enabled
application interfaces and content-driven web sites. Portal
applications can be developed using wizards in a WYSIWYG portal
development environment. Using this environment, you can create and
deploy static and dynamic portal content. Users can be granted access
to the environment to create their own customization. For example,
you can grant an OracleAS Portal user permission to choose which
content areas and links appear in his portal pages.

Java or PL/SQL developers may wish to leverage the functionality of
OracleAS Portal without having to use the Portal Development
environment. For such power developers, Oracle also provides a Java
and PL/SQL Portal Development Kit for custom portlet development or
application integration.

Portals are deployed as an integrated service in Oracle
Application Server and can use directory services, the
OracleAS Web Cache, J2EE services, and business intelligence services
provided by OracleAS Reports Services and OracleAS Discoverer.

The support of portlets enables a single web page to be divided into different areas that can independently display information and interact with the user.

Chapter 13 describes OracleAS Portal in greater
detail.

1.3.3.2 OracleAS Discoverer

OracleAS Discoverer is a business intelligence
tool used for ad hoc queries and user-generated reports. OracleAS
Discoverer also provides an interface to
relational online
analytical processing (ROLAP) by leveraging analytic features present
in the Oracle database and as of 2004, also provides an interface to
the Oracle OLAP Option. Included in Oracle Application Server are:

Discoverer Plus

A Java-based browser client that can be used to generate ad hoc
queries, reports, and graphs

Discoverer Viewer

An
HTML-based browser client that can
execute reports or graphs created in Discoverer Plus or the Desktop
version of Discoverer

Discoverer Portlet Provider

A package used for lists of workbooks
and worksheets

OracleAS Discoverer can leverage the Oracle Application Server Single
Sign-On capabilities and can also export workbooks to Oracle Reports
Developer for deployment in OracleAS Reports Services.

OracleAS Discoverer has an
End
User Layer (EUL) that is metadata-driven, enabling
business definitions to hide and map to underlying technical
descriptions. The EUL is set up and maintained via Oracle Discoverer
Administration Edition, a part of the Oracle Developer Suite. Wizards guide
the administrator through the process of building the EUL. In
addition to managing the EUL, administrators can put limits on
resources available to analysts monitored by the
Chapter 12 describes OracleAS Discoverer in
greater detail.

1.3.3.3 Oracle Internet Directory

The Oracle Internet Directory provides users a
means of connecting to an Oracle server without requiring a
client-side configuration file. The Oracle Internet Directory is a
Lightweight Directory Access Protocol
(LDAP) directory that supports the Single Sign-On capability of
Oracle Application Server.

Chapter 2 and Chapter 4 describe the Oracle Internet Directory in
greater detail.

1.3.3.4 Oracle Workflow

Oracle
Workflow provides a graphical workflow builder
that facilitates the modeling of business processes. A rules-based
engine and business event system is stored in an Oracle database.
Messages can be transmitted via Advanced Queuing (AQ), Oracle Net,
HTTP, or HTTP using SSL (HTTPS). Oracle Workflow provides key
capabilities needed to deploy Oracle Application Server InterConnect,
described in the next section.

Chapter 15 describes Oracle Workflow in greater
detail.

1.3.3.5 Oracle Application Server InterConnect

Oracle Application Server
InterConnect provides a heterogeneous
application integration platform through logic and services. Deployed
in a "hub-and-spoke" manner, Oracle
Application Server leverages Oracle Workflow and Oracle AQ to provide
a message broker infrastructure. AQ
enables asynchronous messages between Oracle databases with adapters
available to extend support to other message types and applications.
Content-based publish-and-subscribe solutions can be deployed using a
rules engine to determine relevant subscribing applications. As new
content is published to a subscriber list, the rules on the list
determine which subscribers should receive the content, thus
efficiently serving the needs of different subscriber communities.

OracleAS InterConnect includes a design-time Integrated
Development Environment (IDE), adapters, a metadata repository, a
management infrastructure (used with Oracle Enterprise Manager), and
SDKs (for writing custom

adapters,
transformations, and IDE extensions). Adapters are available for
HTTP, HTTPS, AQ, Oracle database, FTP, MQSeries, CICS, SAP,
PeopleSoft, Siebel, JDEdwards, and CICS.

Chapter 15 describes OracleAS InterConnect in
greater detail.

1.3.3.6 Oracle Application Server ProcessConnect

Oracle Application Server ProcessConnect is new to Oracle
Application Server 10g. Using wizards to create
a hub-and-spoke deployment model, it's designed to
make business process integration feasible. OracleAS ProcessConnect
includes a modeling tool, a metadata repository, and

adapters. These adapters are based on
the JCA specification and enable connections to technology (such as
Web Services), packaged applications (e.g., JD Edwards, PeopleSoft,
SAP, and Siebel), and legacy systems.

Chapter 15 describes OracleAS ProcessConnect in
greater detail.