Composing Software from an Architecture Description Language (xADL) Specification and an XML Binding Schema.

Nathan Combs, BBN

A simple illustration of how an XML java-binding schema may be used to compose software from a high-level XML "architecture specification".

In this example the "xADL" Architecture Description Language is used to specify an abstract architecture composed of components and connectors... This then is mapped into a toy Java implementation via an XML java-binding schema.

Important to note, xADL is specified by an XML DTD. A DTD is a weak specification which doesn't reflect either type or binding information. Hence, the focus of this experiment (below), was to map xADL into an XML "binding schema" which strongly specifies the mapping from a specification to a specific binding context. In this case, JXML/Quick's QJML schema was used.

An XML "data-only" schema can be provided as compromise between a DTD and a "binding schema". Example, such as JXML/Quick's QDML. This is not illustrated here. Such a model would be a typed data schema which would be agnostic to the implementation bindings -- relying instead on some other representation to capture this.

• xADL DTD
• xADL sample document (planner.xml)
• xADL represented as Quick "java binding schema"
• Java binding sources:

  xADL.java

  Architecture.java

  Topology.java

  AttachableBrick.java

  Component.java

  Connector.java

  Link.java

  AttachableBrickType.java

  ComponentType.java

  ConnectorType.java

• Java driver sample which uses the xADL Quick Java Binding document (above) and parses the xADL sample document (above) and creates/binds data to Java objects (above).
• xADL: Enabling Architecture-Centric Tool Integration With XML
• ArchStudio
• ArchStudio papers

• Components and Connectors subclass "AttachableBrick" base class.
• ComponentType and ConnectorType subclass "AttachableBrickType" base class.
• QJML binding schema doesn't map to the java inheritence hierarchy.. ie. all elements replicate features which are represented in base classes (AttachableBrick, AttachableBrickType). XMLink?

Contact Nathan Combs.
Last modified 18 May 2000 
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