Managing EntitiesThis section describes how to manage entities within the Broker. The principles underlying
entity management are the same regardless of entity type. For this reason, this section begins
with a general description that applies to all.Since not all channels support the management of all entity type, this section commences
with a table showing which entity type is supported by each channel.General DescriptionThe following description applies to all entities within the Broker regardless of their
type.All entities have a parent, and may have children. The parent of the Broker is
called the System Context. It has no parent.Entities have one or more attributes. For example a name, an
id or a maximumQueueDepthEntities can be durable or non-durable. Durable entities survive a restart.
Non-durable entities will not.Attributes may have a default value. If an attribute value is not specified the
default value is used.Attributes values can be expressed as a simple value (e.g. myName
or 1234), in terms of context variables
(e.g.${foo} or /data/${foo}/).Each entity has own zero or more context variables.The System Context entity (the ultimate ancestor of all object) has a context too.
It is read only and is populated with all Java System Properties. Thus it can be
influenced from the Broker's external environment. See QPID_OPTS
environment variable.When resolving an attribute's value, if the value contains a variable
(e.g.${foo}), the variable is first resolved using the entity's own
context variables. If the entity has no definition for the context variable, the
entity's parent is tried, then its grandparent and so forth, all the way until the
SystemContext is reached.Some entities support state and have a lifecycle.What follows now is a section dedicated to each entity type. For each entity type key
features are described along with the entities key attributes, key context variables, details
of the entities lifecycle and any other operations.