NetWeaver 7.3
•The
new version is set to become available at the start of 2011 and provides a
whole range of revised functions. For example, release 7.3 supports Java
EE 5 as well as Enterprise
Service Bus (ESB) for Java. The Java Message Service (JMS) is also new as a
publish-and-subscribe function. Furthermore, SAP NetWeaver 7.3 supports WS Policy 1.2, SOAP 1.2, WS Trust 1.3,
Java SE 6, JSR 168/286, WSRP 1.0, and SAML 1.0/2.0.
Architecture
The AS Java system consists of three logical layers:
•Java Enterprise
Runtime - comprises low-level subsystems that provide functions such as class
loading, cluster communication, persistent configuration data management, and
so on.
•AS Java System
Components - consists of facades, interfaces, libraries and services components
that provide various runtime functions and programming APIs.
•Applications - refers
to the applications that are deployed and run on AS Java.
Architecture
Components
The following types
of components exist:
•●
Facades
– they simplify the
relationships between SAP NetWeaver layers and client applications. Facades are the only
official way for clients to access the AS Java API. They help to define what is
an ‘external (publicly available) API’ and what is an ‘internal API’.
Everything that is part of a facade is public and the client code must be built
against it. Everything that is not part of a facade is not official and the
client code should not rely on it. Clients in this context can be components
from other layers of the product and customer applications. If a client needs a
reference to the public API of a certain component (service, interface, or a
library), it must reference the facade which contains the API of the component.
●
Interfaces
– they define how
different components of the system work together. At runtime, they provide the
system with their name and classes (no objects). They are used by services
components that provide their implementation.
●
Libraries – they provide name,
classes and objects to the system. These objects are created by the system when
it loads the library, or when an object is first requested. Libraries are not
active components – they have no definite life cycle, do not allocate resources
themselves and do not keep any kind of configuration information in the system.
Other library components or services components usually access them using
static methods.
●
Services – they provide the
system with their name, classes, and runtime objects. The runtime objects are
registered in the system once the components classes have been loaded. Service
components can access and utilize functions of the runtime through the Framework
API. Services are active components with a definite life cycle. They can
allocate resources at their startup time and are responsible for releasing them
at shutdown time.
Features
Features
•The
AS Java system architecture is based on the following general rule: components
from a higher level can use components from a lower level only through a set of
defined APIs - facades; whereas components from a lower level are not aware of
the APIs of the components from a higher level and therefore cannot use them.
•This
rule is reflected by the order of starting the system modules: the runtime is
started first, then the services (the libraries are loaded, the interfaces
resolved at this phase), and the applications are started last. The system is
considered as started when all runtime managers and core services components
are started properly.
•The
AS Java system components use the Framework APIs to connect to the Java
enterprise runtime. Applications use the AS Java system components using the
APIs that are defined by Java EE 5 specification (and supporting
specifications) and SAP-proprietary APIs.
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