Content Assembly Mechanism (CAM) business transaction information management What CAM Is The CAM approach provides these three The CAM specification provides an open critical abilities: – XML based system for using business rules to • documentation of business interchange define, validate and compose specific business transactions, documents from generalized schema elements • design-time assembly support with and structures. verification, and A CAM rule set and document assembly • runtime checking of information content. template defines the specific business context, content requirement, and transactional function Next we consider the limitations of current of a document. A CAM template must be approaches and technologies and how the capable of consistently reproducing documents capabilities that CAM provides can address that can successfully carry out the specific these shortcomings. transactional function that they were designed for. CAM also provides the foundation for The Present Tools and Their Limitations for creating industry libraries and dictionaries Addressing the Problem of schema elements and business document structures to support business process needs. The advent of XML has also meant that other new tools are available to advance the technology of automatic transaction content Solving the Inherent Problem of Automated handling. These include formal structure Information Integration definitions using XML schema (XSD) with Automated information integration has content control at the element level using been the Holy Grail of e-Business systems datatyping; then XSLT rules and XPath since before XML was conceived. Early expressions and semantic tools such as RDF attempts centered on the use of industry and OWL to provide machine understanding of standard transaction formats typified by EDI the role and usage of the XML based messages1. information itself. These tools typify the approach of controlling the actual XML These quickly showed that three needs instance documents and their content (e.g. were paramount: the ability to design transactions) by creating formal expression transactions consistently, the ability to language that provides external descriptions document their usage in a clear way and then about the possible instance documents that the ability to drive software that can apply rules are allowed. The W3C organization has and test information content to ensure correct centered its efforts on this strategy2. compliance. People usually start this process by defining an XML schema that contains the 2 The World Wide Web consortium (W3C), were the 1 For more information on Electronic Data Interchange creators of the XML syntax – for more information on (EDI) – see N. American standards secretariat group site: XML. XSD, XPath, RDF and OWL see http://www.disa.org http://www.w3c.org Content Assembly Mechanism Brochure - 2 rules of the actual XML structure they wish to What is CAM comprised of? use. This is often sufficient for simple small A CAM template has five sections: transactions between closed communities of assembly structure(s), business context rules, business partners. However for general content referencing, data validation and communities across whole industries this can external mappings. They can be used rapidly become problematic as more and more altogether or in combination. The first two context driven factors are added to the sections are required; the remaining three are schema, since schema does not have by itself optional, so a CAM template can be as simple a native context driven selection mechanism. or sophisticated as the business needs dictate, Further more a large need is the handling of see figure below. industry lists for standard code values and particularly sub-sets of codes where again can have more than one structure layout schema has no direct built-in method for this. Combined XML with instance can add inline rules directly Another approach is to use UML3 modelling structure(s) into structure techniques to create models of the information + Simple Declarative Statements use cases, classes and instances and then makeOptional() derive XML schema definitions from these Business context rules excludeTree() UML structure diagrams. The ebXML core item type="noun" + Content Reference rules name="Agency/@AgencyID" components work and the OASIS UBL UIDReference="ukt000910" technical work have both used this approach. <conditional + Data Validation rules expression="'//SupplierID' and lookup(value,'SGIRWSDL:sup UML itself however has no mechanisms for plierID_check')" capturing complex cardinality relationships in + External Mapping rules <MapRule output="type" input="Sales/Company/Yea the models. Therefore this approach is limited r/Qtr/Product@type"/> in the same way that XML structure models in XSD are as well. Also industry dictionaries of component definitions are not well integrated What does the addition of context to CAM into UML tools through federated registry do? capabilities. However, CAM supports this In addition the CAM system provides a capability through its direct support for ebXML global context passing mechanism, and an Registry systems and the ability to derive XML rendering for declaring context variables. semantics in XML from such registries. This context mechanism is at the heart of why CAM is so effective. By allowing users to quantify what their context factors are The Issue of Context in Business precisely, this removes the guess work from Interchanges business transaction exchanges between In automating information integration, partners and allows them to formulize their knowing and defining context of use is the collaboration agreements exactly. It also single most pervasive and important factor. makes re-use and identifying potential The older EDI systems however have no way candidate CAM template models much easier. to support dynamic context driven content Simply knowing what the external parameters assembly whereas CAM provides this better are can instantly qualify if a template makes than any other XML syntax system today. In sense for a user and allow them to therefore fact CAM templates work for both old EDI select it. payloads and new XML based transaction structures. 3 Universal Modelling Language (UML) as originally developed in Rational Rose and now part of the Object Management Group (OMG) specifications. Content Assembly Mechanism Brochure - 3 How Does CAM Execute? Each BOD also has associated with it a A CAM implementation requires that a complete list of each information element and reference CAM template be available along basic details of its content. The CAM with the CAM processor engine itself. The technology has been designed fundamentally available jCAM processor4 is implemented in to leverage such dictionaries of noun Java and so can be used in a variety of definitions and so the available OAGi BOD environments. Along with the CAM processor semantics provides the perfect match for this. will typically be an XML instance to be The content reference section of the CAM manipulated by the processor. Also CAM templates provides the means to facilitate this. maybe used as a web service and sample The next section provides and overview of WSDL binding definitions are available to how to use such specific CAM features and facilitate this. techniques. A practical example of what CAM does How Do You Create CAM Templates and Next the following figure shows how the Rule Sets? CAM template details are used to create a There are several steps required in building specific transaction instance. Consider for a CAM template depending on how complete example a scenario from the current you would like your template to be. To fully automotive industry work on aligning inventory utilize CAM you may want to fill out all six control systems using the Open Applications sections of the CAM template. Most initial Group (OAGi) business transaction formats templates however only use two or three called BODs (Business Object Documents). In sections for structure, business context and the case of such OAGi BODs the CAM content reference sections. template provides the context driven rules and The first thing you require when structure instances derived from the master constructing a CAM template is an actual XML BOPD models that given a particular car model of the information structure you wish to manufacturers requirements will create the manipulate. You can either enter this directly actual resolved structure and rules for the OAG from scratch into the CAM template, in XML, or BODs inventory management information you can cut and paste an example from some exchange required. XML that you are already using. So in the example we are considering – you would XML CAM 1 create a sample instance for a car process transaction Template and content manufacturers system of a typical document compare transaction. 4 + 3 Next you go through that XML structure 2 Generates and do four things: actual XML Context instance - mark each field where information will Statements definition occur with the “%%” substitution to be used placeholder CAM gets passed context from business use 5 - physically enter static information Results for exactly as and where it should occur in given the XML context and action - duplicate parts of the structure that may be choices, and label those parts with selection names (e.g. as:choiceID=”USA-address”, and as:choiceID=”Canada-address”) 4 The jCAM processor is open source can the resource site is http://jcam.org.uk for the project. Content Assembly