<?xml version="1.0" encoding="latin1" ?> <!DOCTYPE chapter SYSTEM "chapter.dtd"> <chapter> <header> <copyright> <year>2000</year><year>2009</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> The contents of this file are subject to the Erlang Public License, Version 1.1, (the "License"); you may not use this file except in compliance with the License. You should have received a copy of the Erlang Public License along with this software. If not, it can be retrieved online at http://www.erlang.org/. Software distributed under the License is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the specific language governing rights and limitations under the License. </legalnotice> <title>The Notification Service Components</title> <prepared>Niclas Eklund</prepared> <docno></docno> <date>2000-04-13</date> <rev></rev> <file>ch_system.xml</file> </header> <section> <title>The Notification Service Components</title> <p>This chapter describes the Notification Service Components and how they interact.</p> <section> <title>Components</title> <p>There are seven components in the OMG Notification Service architecture. These are described below: </p> <marker id="notificationFlow"></marker> <image file="notificationFlow.gif"> <icaption> Figure 1: The Notification Service Components.</icaption> </image> <list type="bulleted"> <item><em>Event Channel:</em> acts as a factory for Administrator objects. Allows clients to set Administrative Properties.</item> <item><em>Supplier Administrators:</em> acts as a factory for Proxy Consumers. Administrators are started as <c>'AND_OP'-</c> or <c>'OR_OP'-</c>type, which determines if events must be validated using both the Administrators associated Filter and/or its Proxy children Filters.</item> <item><em>Consumer Administrators:</em> acts in the same way as Supplier Administrators but handle Proxy Suppliers.</item> <item><em>Consumer Proxy:</em> is connected to a client application. Can be started as <c>Pull</c> or <c>Push</c> object. If the proxy is Push style the client application must push events to the Proxy, otherwise the Proxy is supposed to Pull events. The <c>CosNotification::AdminProperties</c> is used to set the pacing interval.</item> <item><em>Supplier Proxy:</em> Acts in a similar way as the Consumer Proxy, but if started as a <c>Push</c> proxy it will push events to the client application.</item> <item><em>Filters:</em> used to filter events. May be associated with Proxies and Administrators.</item> <item><em>Mapping Filters:</em> used to override events Quality of Service settings. Can only be associated with Consumer Administrators and Proxy Suppliers.</item> </list> <p>When a Proxy is started it is set to accept <c>CORBA::Any</c>, <c>CosNotification::StructuredEvent</c> or <c>CosNotification::EventBatch</c> (a sequence of structured events).</p> <p>If a Proxy is supposed to deliver structured events to a client application and receives an <c>CORBA::Any</c> event, the event is converted to a structured event with <c>type_name</c> set to <c>"%ANY"</c> and the event is stored in <c>remainder_of_body</c>.</p> <p>If a Proxy is supposed to deliver <c>CORBA::Any</c> events to a client application and receives a structured event, the event is stored in an Any type. The Any Type Code will be equal to the <c>CosNotification::StructuredEvent</c> Type Code.</p> </section> </section> </chapter>