Installation and Update Framework

2.6.1 Installation and Update Framework

The SAP NetWeaver Developer Studio uses the standardized Eclipse framework to ensure the installation of the developer tools and their continual update. Therefore, we will briefly go into the components involved and by doing this explain the underlying concepts and the functioning of the installation and update framework.

Products and Features

Features as installable units

Autonomously executable applications that are based on the Eclipse platform are managed as products, in accordance with the Eclipse nota-tion. A product is comprised of one or more features, which in turn each bundle a set of plug-ins to units that can be installed together. In other words: Eclipse features represent a means to technically classify an Eclipse product as a unit and to describe its functions.

Features are used to group together plug-ins that provide the actual functions of a product. However, features do not contain executable code, but only a metadata description. In essence, this metadata delivers a compilation of plug-ins, which together define the functions in a spe-cific feature. Furthermore, it contains information about how to install or update this metadata for a newer version. As a result, a feature defines the smallest unit of downloadable and installable functions in an Eclipse product. The modular structure of Eclipse products therefore allows subsequent installation of additional features and plug-ins or update of the existing product features and plug-ins.

Update manager Generally, this can happen using a conventional installation, completely independent of Eclipse, or using the update manager, which is part of the Eclipse platform. The update manager is a basic component of the standardized installation and update framework of the Eclipse platform.

The tasks of the update manager include locating, downloading, and installing the features and plug-ins to be updated, starting from an update site specifically configured for this purpose by the administrator within the system landscape.

Update site and update policy

However, the prerequisite for referencing this local update site is a redi-rection mechanism. An update site URL in the form of a symbolic name is assigned to each feature when it is created. The update manager uses

Installation and Update — Outlook 2.6

this URL when a feature update is requested and is redirected to the local update site by means of an update policy. The update policy is stored in the form of an XML file and contains the entry for the update site URL that is configured locally. In turn, the policy is referenced using an entry on the corresponding Preferences page in the Developer Studio.

The basic framework schema can be identified easily in Figure 2.22:

basic feature of the IDE, on the developer’s local PC using a specific installer for this purpose. As a result of this installation, the update manager is then available as part of the NWDS platform.

Developer Studio starts automatically and launches the update man-ager; subsequently, the other features can be requested for local download.

update site, which retains a list of all installable features. This list bun-dles the features in question into installable units that are called main features later in this chapter. All features of this type are based on the NWDS platform. Moreover, the dependency of features on each other is taken into account during the installation process so that all depen-dent features are automatically installed as well.

Figure 2.22 Affected Components and Basic Process for NWDS Installation and Update

Overview of the SAP NetWeaver Developer Studio

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The SAP NetWeaver Developer Studio uses precisely this standardized Eclipse framework to ensure the installation of tools and their continual update. The update site for the Developer Studio can be in various loca-tions: On the one hand, it can be a local copy of the installation DVD (offline installation) or a global SAP update site that can reached through SAP Service Marketplace (http://service.sap.com) or through SAP Devel-oper Network (http://sdn.sap.com, online installation). Another option available is the NWDS update site, which can also be installed locally as part of a reference J2EE system within the customer landscape.

The basic update procedure can be described as follows: Each installed feature and each plug-in contained in a feature is stored, usually as a JAR file, below the IDE installation directory in a subdirectory with a name that contains a version ID. With each new update, the system automati-cally creates a new subdirectory containing the associated JAR file. As a consequence, different versions of a feature or plug-in lie in separate directories. This ensures that there can be more than one version of one and the same feature or plug-in on the local hard disk.

This means that each feature update also entails the local storage of addi-tional files because the files to be updated are neither deleted nor over-written. As soon as all associated files are available in a new version in the installation directory on the hard disk, a new feature configuration is compiled. The crucial, new features and plug-ins are activated and the previous versions are deactivated.

Feature configurations

As a result, the IDE supports several configurations at the same time, although only one configuration can be active. Configurations can be explicitly saved to revert to if the need should arise.

Very comprehensive products, such as the SAP NetWeaver Developer Studio, organize the features to be installed in tree hierarchies. The root node represents the overall product and includes smaller units, which include the NWDS platform, certain main features, and possibly certain other optional features. The last features in this list are often called add-ons.

Version labeling for features

In the SAP NetWeaver Composition Environment, the Developer Studio could display a tree structure such as the one shown in Figure 2.23. As you can see in this figure, the product is characterized by a set of

fea-Installation and Update — Outlook 2.6

tures: The associated version label (CE 7.1) follows the name (in the fig-ure: SAP NetWeaver Developer Studio), the version ID is followed by the version number of the service package (SP03), and finally the num-ber of the patch level (PAT0000). The installable main features are iden-tified by their names and the feature version.

NWDS Platform

The NWDS platform is a basic unit of the Developer Studio, which is the very first feature installed. The NWDS platform is not installed using the update manager, but using a special platform installer.

Platform installer

When the NWDS platform has been installed on the local PC, developers can start the Developer Studio to download the other features using the update manager.

The NWDS platform contains the Eclipse platform, which also includes the Eclipse update manager, and an NWDS branding plug-in with all remaining components that are responsible for the update process. The platform installer also configures the update policy (policy.xml) and therefore defines the URL for the location of the update site.

Main Features

Main features as installable units

Each main feature is a clearly defined set of plug-ins that are always installed and updated together. However, they form not only a technical unit, but also a semantic one, which is usually orientated to a stand-alone use case. For example, the following main features are potential candidates:

Figure 2.23 Possible Selection During Feature Installation of the Developer Studio for the Composition Environment

Overview of the SAP NetWeaver Developer Studio