Brief Introduction to CosMIC:
The Component Synthesis
using Model Integrated Computing (CoSMIC) project is a MDA toolset being
developed by the Institute for Software Integrated Systems (ISIS) at
1. Model and analyze distributed real-time and embedded application functionality and QoS requirements.
2. Synthesize CCM-specific deployment metadata required to deliver end-to-end QoS to DRE applications.
The CoSMIC toolsuite provides modeling of DRE systems, their QoS requirements, and QoS adaptation policies used for DRE application QoS management. The component behavior, their interactions, and QoS requirements are modeled using a domain specific modeling language that adheres to the OMG Deployment & Configuration (D&C) specification (ptc/2003-07-08). CoSMIC enables modeling the standards-based CCM components.
Hand-writing the required XML descriptors to configure our components is tedious and error prone. We therefore utilize CosMIC (we specifically use a subset of CosMIC called PICML, which stands for Platform-Independent Component Modeling Language) to generate the bulk of descriptors for us.
For more information on CosMIC, please refer to the following article:
CoSMIC: An MDA Generative Tool for Distributed Real-time and Embedded Applications.
Importing IDL to PICML
To quick start our Stock Quoter modeling process in GME, CoSMIC
introduces idl_to_picml , which is an executable program that imports
the IDL files you just created into PICML.
%COSMIC_ROOT%\bin
is included in
the PATH variable, e.g., c:\Program Files\ISIS\CoSMIC\bin.
Quoter\Simple
, and type the
following command: Quoter.xme
file in the
Quoter
directory. Note that if
-x option is not used, the default xme file name will be PICML_default_xme_file.xme.
Figure 2
In the Browser of the generated model, the PredefinedTypes folder contains a bunch of atomic datatype elements that will be referenced by other modeling parts later. You don't have to worry about them for now. The models in InterfaceDefinitions folder are the PICML representations of the IDL files you just imported. Double-click to open StockBroker, it will show you a yellow box-shaped entity representing a <<Package>> instance. Its equivalent representation in IDL is "module". Figure 3 gives you a clear view of GME representation of all the 3 IDL files created. We will cover the other folders in the next section.
Figure 3
Now
we are ready to model the rest of the Stock Quoter systems.
This section describes modeling the Quoter application using PICML. If you have trouble producing a functioning model from this tutorial, please see the, pre-built Quoter model which is provided for your reference. This model contains all elements created as part of this tutorial.
Note: To import an XML file in GME, select File | Import XML... from GME and choose your XML model
The PICML paradigm is designed for the OMG Deployment & Configuration (D&C) specification (ptc/2003-07-08), so the modeling process is straightforward if you are familiar with the specification. Please see the DAnCE project for more information. For those who hate specifications (including me, :-)), an overview of D&C and as well as a tutorial of D&C and CCM can help to reduce the learning curve. In addition, it is also helpful to read through documentation which originally came from the TAO's Developer's Guide 1.4a (CIAO and CCM) which thoroughly describes the various descriptors required for a component (*.iad, *.ccd, *.cid, etc). This chapter is available here.
The complete PICML Quoter model consists of modeling elements distributed across various folders. If you used idl_to_picml to generate the initial model, you will see that it has created all these folders and some of the tedious boilerplate modeling for us. The rest of the section will explain the purpose of each folder as well as the modeling entities contained in these folders. We will also show how to model some of the folders that have to be done by hand.
Important: The interpreters that generate deployment artifacts expect very strict constraints in the model. When you finish your model, and any time you wish to generate anything, it is a good idea to check constraints by clicking on Tools | Constraints | Check All in GME. This will help you find many logic errors in your model.
This folder contains implementation artifacts associated with components. idl_to_picml has created these artifacts for us to ensure the are named correctly when associated with their target implementation. Figure 4 shows the Implementation Artifacts for the StockBroker implementation.
Figure 4.
This folder contains models that describe the implementations of component interfaces. In the Quoter example, we will have two monolithic component implementations - named Stock_StockDistributorImpl and Stock_StockBrokerImpl - and an assembly component implementation named StockQuoter, which is an assembly of Stock_StockDistributorImpl and Stock_StockBrokerImpl. idl_to_picml has created the monolithic component implementations for us, as shown in Figure 5.
Figure 5
We also need to specify the connections between a Stock_StockDistributorImpl and a Stock_StockBrokerImpl in order to construct a Quoter system. We therefore we need to create the mentioned StockQuoter component assemby.
Assembly components provide a boundary for the composition
of monolithic components and even other assemblies. Assembly components do not
provide actual implementations for their interface, it is a virtual component
that delegates its ports and attributes to one or more of the entities it
contains. There are slight differences between modeling an assembly and
modeling a monolithic component. Since the assembly is a virtual component, it
is not necessary to model a MonolithicImplementation
.
Instead, instances of other components are placed within the assembly
and connected. Let's try to assemble the StockQuoter.
Figure 6
Figure 7
This folder contains domain-specific models capturing information about the target environment in which component-based application will be deployed. In this Quoter example, we can either deploy the two components into ONE host, or into TWO different host. We will deploy the Quoter into two different host.
Now we are ready to deploy our Components to the actual physical environment.
This folder contains a plan model that captures information about the assignment of component to nodes.
Quoter/Targets/Domain/Broker
and
Quoter/Targets/Domain/Distributor
respectively. Quoter/ComponentImplementations/StockQuoterImplementation/StockQuoter/StockBroker
and Quoter/ComponentImplementations/StockQuoterImplementation/StockQuoter/StockDistributor
respectively.The model should look like this:
Figure 10.
Figure 11
Now move your cursor to <<ComponentInstanceRef>> StockDistributor, and left-click it, so that it looks like Figure 12.
Figure 12
This operation associates StockDistributor component to the <<CollocationGroup>> running on Distributor node. To do the same with Broker, just right-click on the associate <<CollocationGroup>>, and left-click on StockBroker <<CollocationGroup>> which is then highlighted.
Up to this point, we are basically done with the modeling part. Before we generate anything from this model though, please DO remember to check the constraints of the model as we mentioned earlier.
After we are done with the modeling, the Deploymentplan interpreter that comes along with PICML will help us to generate a Plan.cdp file. Please make sure you generate this file to Quoter/descriptors. Note that to get the example working,a Node Map xml file (NodeMap.cdd) in Quoter/descriptors should be created to map logical nodes to NodeManager object references.
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