An Act ive Universal Resource Accessor. An Active URA is similar to a URA.
It is generative source of resources.
Active URAs are the standard means to wrap a procedural transform or custom processing task. Active
URA's can be created for any application and discovered by the system.
Applications are modular collections of resources that collectively comprise a functional
process. Generally applications consist of linked modules holding declarative XML, URA components and general resources.
Applications are dynamically discovered and linked using the XAR module infrastructure.
A detailed discussion of the module manager and of how modules are combined into applications is available here.
An Aspect is an immutable Application Programming Interface (API) to retreive
state from a Representation. Each aspect exposes a different style of access.
This is a little abstract so an example might help. A representation of an
XML document might expose an unparsed binary aspect, a DOM aspect, and a
SAX streaming aspect.
The 1060 kernel caches all resources. If the resource is XML it is parsed and cached therefore avoiding frequent parsing
overhead for heavily used resources.
Provided the basic root element is b and it's text value is either t or f then it is a valid boolean, even if the root element possesses
child elements.
Declarative Processing Markup Language. DPML is the first XML processing language supported
by the 1060 NetKernel. A reference guide to DPML is available here.
An in depth tutorial is here.
A Fulcrum is a module which is not imported by any other module. It is the root module of a tree
of modules that comprise an application. In general a fulcrum imports and starts an application's
transports.
The kernel coordinates and manages all processes. It handles resource caching, application scheduling,
exception handling, together with managing the discovery and dependencies of pluggable system components.
A discussion of the Kernel's process execution cycle is given below.
A literal within DPML is an inline XML document appended below a parent element. A literal must have only a single root node. Literals are
frequently used as static operators.
In the context of the NetKernel MetaData is data about a resource that is not the
resource itself. Representations of a resource expose an IURMeta interface which
gives information on type, validity and cost of creation.
A DPML construct. An operator is the XML resource that specifies how an operand is to be processed. In the
case of a generative URA the operator specifies how to create a resource.
A Representation is an in-memory object which acts as a proxy to a universal resource. It contains
metadata about the resource and a number of aspects.
A transport is a modular component
that services external requests and provides a mapping from the request to an internal kernel resource request.
Typical transports include HTTP, SOAP, SMTP, JMS, BEEP ... Transports are
dynamically discovered using the XAR package infrastructure. More information on creating transports
is available here
Transrepresentation is the process of changing a representation of a resource. It involves
creating alternate aspects and is usually implemented by a Transreptor.
A URA is a component that may receive requests for resources from the NetKernel.
A URA may also issue requests for resources to the NetKernel. A URA may be thought of as a destination
endpoint for a given URI resource reference. More information on creating URAs
is available here. Note: The use of 'Universal'
as opposed to 'Uniform' is deliberate and not a corruption of URI.
A Uniform Resource Identifier. URI is a generalization of the most common form, the URL.
The kernel uses URIs to access all resources.
See also W3C URI Specification
The Universal Resource Identifier Infrastructre (URII) consists of URI Mappings to Universal Resource Accessors. Accessors are used to source and sink
resources. Typical resource providers include local filesystem, HTTP, SMTP, SQL Databases, SOAP etc. URAs can also be generative
resource constructors and can embody encapsulated custom processing for application specific processes and business logic.
The URII is a generalized system for resolving and servicing requests for Universal Resource Identifiers.
More information on creating URAs is available here
XML Access Control Markup Language. The 1060 kernel offers XACML to provide a generic, transport independent, policy-based access control model
to applications and resources. XACML is available as a URA for use in XML applications.
An XML Application Package in a Zipped Module archive. XAR's are similar to Jar or War files. XAR's contain resource modules and are
dynamically discovered. See module.
It is very convenient to describe the sequencing of transports, resources and URA's using declarative XML processing languages.
Language support is modular, provided by URA's, and languages may be added or extended. By default the NetKernel provides
the DPML declarative XML processing language URA. In future other languages will be added.
