Overview

Configuration Repository

The diagram above provides a high level depiction of the X Platform's configuration architecture. Salient aspects of this architecture are:

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• XML Descriptor: The platform allows an application to describe an application's entire configuration in XML form and programmatically initialize a repository using the XML descriptor. XML Configuration is defined by the Domain Descriptor Language schema, x-ddl.xsd. This is the recommended mechanism if an application can store the platform configuration in XML form, or can convert the configuration from its own form to XML to be supplied to the platform for configuration. 
  • The application should use the com.neeve.VMConfigurer class to configure the platform using an XML descriptor
  • The XML Descriptor is described by its corresponding x-ddl.xsd schema. Usage of XML is described below, and in even greated detail in the DDL Schema Reference documentation.

• Component Descriptors: Each platform component is accompanied by a companion configuration descriptor that is used to programmatically configure the component. In addition to implementing setters and getters to set and get configuration attributes, descriptors also implement the ability to save configuration properties to the repository. This allows for application code to programmatically seed configuration information into the repository. This mechanism is suited for use when platform related configuration cannot be easily transformed to XML form. The following are the various descriptor classes:
  
  

  Component Name	Descriptor Class	Description
  SMA Bus	com.neeve.sma.MessageBusDescriptor	Configures a Bus
  SMA Channel	com.neeve.sma.MessageChannelDescriptor	Configures a Bus Channel
  ODS Store Descriptor	com.neeve.ods.StoreDescriptor	Configures the Store for an Engine (providing HA)
  ODS Store Replicator Descriptor	com.neeve.ods.StoreReplicatorDescriptor	Configures store replication to backup members
  ODS Persister	com.neeve.ods.StorePersisterDescriptor	Configures store disk persistence
  ODS ICR Descriptor	com.neeve.ods.StoreInterClusterReplicatorDescriptor	Configures store inter cluster replication (e.g. remote data center)
  AEP Engine	com.neeve.aep,AepEngineDescriptor	Configures the applications AepEngine
  XVM (Talon Server)	com.neeve.server.config.SrvConfigDescriptor	Configures an XVM

  Note, that with the exception of the SrvConfigDescriptor, it is possible for an application to augment configuration seeded by the XML configuration descriptor programattically with the component descriptor:
  
  

  Code Block
  java java
  @AppInjectionPoint public void setAepEngineDescriptor(AepEngineDescriptor appDescriptor) { appDescriptor.setAppExceptionHandlingPolicy(LogExceptionAndContinue); appDescriptor.save(); if(appDescriptor.getStore() != null) { StoreDescriptor storeDescriptor = StoreDescriptor.load(appDescriptor.getStore()); storeDescriptor.setPersistenceQuorum(1); storeDescriptor.save(); } }

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X supports describing and initializing platform configuration using XML via its Domain Descriptor Language schema (x-ddl.xsd). This section describes commonly used DDL configuration elements. More detail can be found in DDL Schema Reference, which discusses all of the attributes in more detail. 

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