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					 openadaptor 3.2

openadaptor™ Feb 2007   1
What is openadaptor?
Openadaptor is a Java software toolkit for Enterprise Application Integration. It was
written to help a large financial organisation integrate it’s applications with Message
Oriented Middleware. The toolkit provides a framework and components for building
links between systems and various middleware solutions, what we call an adaptor in
this case.

The toolkit provides software components for connecting to a variety of transports
(e.g. JMS, Tibco, RDBMS, SOAP, HTTP, SMTP, Files). It provides components for
“working with” different data representations (e.g. XML, JDBC result sets, fixed width
and delimited string records); however it is not tied to any specific data

The framework includes support for transactions (local or JTA), the ability to capture
and manage processing exceptions and remote administration (JMX or HTPP). The
components can be quickly “wired together” and allow a developer to deliver a
production quality adaptor extremely quickly.

The framework is designed to be as lightweight as possible it does not require any
infrastructure other than the Java Runtime Environment. The framework can be used
to run adaptors as standalone process, embedded in other software or deployed
within application containers. The components can be used with or without the
framework and writing custom components does not require extensive knowledge of
the framework.

All openadaptor components are Java Beans and can be used with the spring
framework ( This means that adaptor processes
can be developed by writing an XML configuration file rather than having to write and
compile Java code.

                             openadaptor™ Feb 2007                                        2
Give me an example?
The possibilities for using openadaptor are broad. It can be used to link enterprise
systems to a core middleware solution or it can be used to link systems together
directly. It can even be used to do simple file transformation. Its flexibility reflects the
technological diversity of the large organisations in which it is used.

For example you may want to poll an application database for events, extract the
data that relates to those events, transform the data to an XML document and
publish to a JMS topic. openadaptor has components to do all of this and this simple
adaptor can be assembled by configuring the components and wiring them together
in a simple “Pipeline”.

                                    JDBC                              JMS

                                     Read                             Write
                                   Connector                        Connector


All of this can be achieved by writing a short XML configuration file. We provide a
standard program to run the configuration as a stand alone process. However you
are free to “wire the components together” using a few lines of Java code or to
embed the XML configuration in any other process that uses the spring framework.

Functionality can be added to the adaptor by inserting additional components in the
“pipeline”. For instance you may want to filter out certain data, transform it into your
company’s enterprise business model and perhaps validate it before publishing it.

               JDBC                                                                           JMS
                                                  XML             XSLT            XML

                Read             Filter                                                       Write
                                                Converter       Processor       Validator
              Connector                                                                     Connector


The adaptor can easily be system tested, by swapping out the transport specific
connectors with file based connectors. When the components are used with the
framework you automatically receive the benefits of the framework, for example
standardized process management and remote administration.

                                          openadaptor™ Feb 2007                                         3
The three fundamental components in openadaptor are as follows…

           Read Connector                                           These connect to an external resource and
                                                                    receive / poll data

           Processor                                                These operate on data, either by transforming
                                                                    it in someway or discarding it

           Write Connector                                          These connect to an external resource and
                                                                    send / publish data.

Logically an adaptor looks like this…

           External                                                                                           External
                                   Read                                                       Write
           Resource                              Object[]     Processor          Object[]                     Resource
                                  Connector                                                 Connector
              A                                                                                                  B

In that every adaptor will have one or more read connectors, zero or more
processors and one or more write connectors. These are typically chained together in
a “pipeline”. The data that “flows through the pipeline” is an array of “Plain Old Java

The simplest adaptor it is possible to configure looks like this…

                        External                                                            External
                                                Read                   Write
                        Resource                                                            Resource
                                               Connector             Connector
                           A                                                                   B

Processors components can be chained together like this…

External                                                                                                                    External
                       Read                   Processor              Processor               Processor            Write
Resource                                                                                                                    Resource
                      Connector                   1                      2                       3              Connector
   A                                                                                                                           B

As stated above, an adaptor can have multiple write connectors, like this…

           External                                                            Write               External
                                   Read                 Processor
           Resource                                                          Connector             Resource
                                  Connector                 1
              A                                                                 1                     B

                                                                               Write               External
                                                                             Connector             Resource
                                                                                2                     C

                                                openadaptor™ Feb 2007                                                             4
Adaptors can also have multiple read connectors, like this…

       External      Read                                    External
       Resource     Connector      Processor                 Resource
          A            1                                        B

       External      Read
       Resource     Connector
          C            2

Adaptors can also have multiple distinct “pipelines”, like this…

       External      Read                          Write     External
       Resource     Connector                    Connector   Resource
          A            1                            1           B

       External      Read                          Write     External
       Resource     Connector                    Connector   Resource
          C            2                            2           D

For simple adaptors (see example spring configurations and code) a developer only
needs to deal with Connectors and Processors and specify how they are “chained
together”. The standard framework Adaptor and Pipeline components will “auto box”
the Connectors and Processors in the appropriate adaptor framework components.

The rest of the section provides more details about the adaptor framework.

Within the adaptor framework the Connectors and Processors are wrapped inside
Node components. These provide the lifecycle management, exception capture,
transaction management and data batching capabilities of openadaptor. There are
specific subclasses of Node for the different fundamental components.


       Read Node                          Read Connector (and optionally a Processor)

       Processor Node                     Processor

       Write Node                         Write Connector (and optionally a Processor)

Where as the fundamental components (Connectors and processors) are data
agnostic, the adaptor components expect to receive data wrapped in a Message
object and respond with a Response object. These are used to propagate context
information such as the transaction and the actual data, discarded data and
processing exceptions.

                                openadaptor™ Feb 2007                                    5
Nodes are typically managed by an Adaptor component. This co-ordinates the
lifecycle and allows Adaptor Read Nodes to initiate the processing of messages. The
following diagram illustrates a typical adaptor configuration.


                                                    Message / Response

                 Message / Response                                      Pipeline / Router

                                                    Message / Response                       Message / Response

                        Read Node                     Processor Node                             Write Node

External                                                                                                                  External
Resource      Read                  Processor                                       Processor                   Write     Resource
   A                                                    Processor                                                            B
            Connector               (optional)                                      (optional)                Connector

A Pipeline / Router is a component that “knows” how the Nodes are chained together.
A Pipeline is actually a simple case of a Router. It can be used when the linkage
between the adaptor components is a non-branching chain and there are no complex
exception capture and routing requirements. The advantage of using a Pipeline is
that it requires less code (or configuration if you are using the spring framework) to
assemble. The Router allows more sophisticated routing and exception

The Adaptor delegates the message routing to a Pipeline or Router. But it is worth
noting that all the adaptor components (Node subclasses, Adaptor, Router and
Pipeline) actually implement the same interface (IMessageProcessor). So it is
perfectly legitimate to couple Nodes together directly or for an Adaptor to delegate
directly to a Node. You are also free to develop complimentary frameworks which use
Nodes, Connectors, Processors, Routers and Pipelines.

                                             openadaptor™ Feb 2007                                                              6
Key interfaces and classes
The components described in the previous section are illustrated in the following
class diagram.

        java.lang.Runnable                                                                               org.oa3.core.IMessageProcessor

                                                                                                               Response process(Message)

                                                                implements      has a                                  implements     has a                                implements

              extends                                                    .Adaptor
                                                      org.oa3.core.adaptor                                      org.oa3.core.node.Node                             org.oa3.core.router.Router

  org.oa3.core.lifecycle.IRunnable                                                                                                                                           extends
                                                     has one or more
          int getExitCode()



                                                                                                                       may have a

                     implements                                                                            extends                      extends

                                                 org.oa3.core.node.ReadNode                                                                                            org.oa3.core.node.WriteNode

                                                             has a                                                                                                                  has a

                                                 org.oa3.core.IReadConnector                                org.oa3.core.IDataProcessor                                org.oa3.core.IWriteConnector

                                                           connect()                                              Exception[] validate()                                          connect()
                                                          disconnect()                                                    reset()                                               disconnect()
                                                             isDry()                                             Object[] process(Object)                                  Object deliver (Object[])
                                                       Object[] next(long)
                                                   Object getReaderContext()

The following interfaces and classes are core to lifecycle management.


                                  implements                                   implements

     org.oa3.core.lifecycle.Component                                          ILifecycleComponent

                                                                               boolean isState(IState)
                                                                            addListener(ILifecycleListener )
                                                                          removeListener(ILifecycleListener )


 org.oa3.core.lifecycle.LifeCycleComponent                           org.oa3.core.lifecycle.LifecycleDelegate
                                                                              IComponent conponent
                                                     has a
                                                                                   String getState()                                          org.oa3.core.lifecycle.ILifecylceListener
                                                                                   setState(String)                       has zero
                                                                               boolean isState(IState)                    or many                stateChanged(IComponent, IState)
                                                                             boolean waitForState(IState)
                                                                            addListener(ILifecycleListener )


                                                          openadaptor™ Feb 2007                                                                                                              7
Distribution and Code Organisation
The distribution of openadaptor contains jar files, example code and documentation.
There are a number of jars

openadaptor.jar                   The openadaptor code

openadaptor-depends.jar           The single jar of the core third-party code upon
                                  which the openadaptor code depends

openadaptor-spring.jar            The openadaptor code that is complimentary to
                                  the spring framework

The example code area contains readme files that describe how to correctly setup
the java classpath.

The package structure of openadaptor is split as follows

org.openadaptor.core                 Contains core interfaces and implementations

org.openadaptor.auxil                Contains connectors and processors that rely
                                     on the core java and javax packages.
                                     Processors that convert between data
                                     representations are referred to as convertors.

org.openadaptor.thirdparty contains connectors and processors that rely
                           on third-party software

org.openadaptor.spring               Contains components that directly use the
                                     spring framework

Why the re-write?
Openadaptor was originally developed in 1997, this predated the popularity of XML
and integral to openadaptor was a canonical data representation called DataObjects.
DataObjects have long been regarded as non-strategic.

Certain standards and technologies have evolved that we wish to accommodate.

Using components of openadaptor outside the adaptor paradigm is difficult as is
extending it to provide more sophisticated functionality such as workflow.

Like allot of software that has been incrementally developed, some of the design and
implementation was sub-optimal but retained because we didn’t want to break
interfaces. The latest version of the openadaptor.jar is 400K compared to the
previous release which was over 2Mb, this reflects how we have attempted to “boil
down” openadaptor to what we feel is original and worthwhile.

                            openadaptor™ Feb 2007                                     8

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