blob: 8dce5dac6d305c0529db502b131d7ee5ca19bebf [file] [log] [blame]
<?xml version="1.0"?>
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
KIND, either express or implied. See the License for the
specific language governing permissions and limitations
under the License.
<section xmlns="" version="5.0" xml:id="Java-Broker-Concepts-Overview">
<para>The Broker comprises a number of entities. This section summaries the purpose of each of
the entities and describes the relationships between them. These details are developed further
in the sub-sections that follow.</para>
<para>The most important entity is the <emphasis>Virtualhost</emphasis>. A virtualhost is an
independent namespace in which messaging is performed. A <emphasis>virtualhost</emphasis> exists
in a container called a <emphasis>virtualhost node</emphasis>. A virtualhost node has exactly
one virtualhost.</para>
<para><emphasis>Ports</emphasis> accept connections for messaging and management. The Broker
supports any number of ports. When connecting for messaging, the user specifies a virtualhost
name to indicate the virtualhost to which it is to be connected.</para>
<para><emphasis>Authentication Providers</emphasis> assert the identity of the user as it connects
for messaging or management. The Broker supports any number of authentication providers. Each
port is associated with exactly one authentication provider. The port uses the authentication
provider to assert the identity of the user as new connections are received.</para>
<para><emphasis>Group Providers</emphasis> provide mechanisms that provide grouping of users. A
Broker supports zero or more group providers.</para>
<para><emphasis>Access Control Provider</emphasis> allows the abilities of users (or groups of
users) to be restrained. A Broker can have zero or one access control providers.</para>
<para><emphasis>Keystores</emphasis> provide a repositories of certificates and are used when the
Broker accepts SSL connections. Any number of keystore providers can be defined. Keystores are
be associated with Ports defined to accepts SSL.</para>
<para><emphasis>Truststores</emphasis> provide a repositories of trust and are used to validate a
peer. Any number of truststore provides can be defined. Truststores can be associated with Ports
and other entities that form SSL connections.</para>
<para><emphasis>Remote Replication Nodes</emphasis> are used when the high availability feature is
in use. It is the remote representation of other virtualhost nodes that form part of the same
<para><emphasis>Loggers</emphasis>, at this point in the hierarchy, are responsible for the
production of a log for the Broker.</para>
<para>These concepts will be developed over the forthcoming pages. The diagrams below also help
put these entities in context of one and other.</para>
<title>Message Flow through Key Entities</title>
<imagedata fileref="images/Broker-MessageFlow.png" format="PNG" scalefit="1"/>
<phrase>Message Flow through the Key Entities of the Broker</phrase>
<title>Broker Structure showing major entities</title>
<imagedata fileref="images/Broker-Model.png" format="PNG" scalefit="1"/>
<phrase>Broker Structure</phrase>