December 13, 2000, 3:45 PM —
CREATING AND deploying e-business applications that leverage open-source
technologies can be a new but worthwhile experience for corporate developers. Linux
isn't the only thing coming from the open-source community; there are business
applications, development tools, databases, and more. You'll still need to purchase
support for these products and orient your staff to a new way of thinking about
software. But it is a cost-effective solution for corporate application frameworks that
closely rival commercial software products.
Lutris Technologies' Enhydra is already the No. 1 open-source application server
and is also making a push into the commercial space. The company has provided
developers with a rich set of tools that rivals competitors such as BEA's WebLogic and
IBM's WebSphere. Enhydra's Version 3.0, standard edition gives developers a rich set of
tools for server-based Java applications, including such facilities as databases, load
balancing, DHTML, XML, and WML (Wireless Markup Language). The product comprises the
Enhyrda Multiserver, Enhydra Director, a broad assortment of APIs and services, and
Presentation, Session and Database Managers.
This version lacks the enterprise middleware coverage of Java 2 Enterprise Edition
(J2EE), such as Enterprise JavaBeans and a CORBA object broker. However, if your
applications don't need all the J2EE components, this server will drastically lower
your development and deployment costs. The standard release of Enhydra is smaller and
lighter than J2EE, more versatile in its deployment, and considerably less expensive:
less than $200 (approximately; pricing was not confirmed at press time) for the
commercial release, which includees documentation, platform certification, and support,
or free for a downloadable version.
Enterprise and professional versions of Enhydra will be released later this year;
the enterprise version, expected to be priced at less than $1,000, will meet the needs
of higher-end settings that require J2EE support. Until then, bear in mind that the
commercial version may not include up-to-the-minute releases of its components
(although they're always downloadable from
an approach pioneered by commercial Linux vendors, makes support and development
assistance services possible.
I tested the second beta release of Enhydra 3.0 on a group of machines running
Solaris 7, Windows 98, Windows 2000, and Red Hat Linux 6.2. Lutris automated most of
the installation under Linux and Windows, with the Windows installer taking care of
almost everything. I did have to manually configure one Windows-specific facility:
Enhydra's Internet Information Server (IIS) interface. This well-documented process
took only minutes.
Enhydra features a capable and flexible architecture that's very practical for
commercial applications. When deployed on a Java-capable Web server such as Apache
(with JServ) or Netscape/iPlanet Enterprise Server, developers can treat Enhydra like a
big Java-class library. Server-side Java applications, triggered by user requests to
the Web server, call into Enhydra classes through a server-side Java applet. This
approach supports the full range of Enhydra features, but it doesn't scale well: The
Enhydra classes and your Web server execute on the same host.
To achieve the scalability and reliability benefits of a multiserver deployment,
Enhydra itself can run as a server. The Enhydra Multiserver uses HTTP, Java Remote
Method Invocation, CGI, and Netscape/iPlanet Web Application Interface to communicate
with applications.
One of the server's most enticing features is the Enhydra Director, which is
sandwiched between the Web server (or other Java server application) and Enhydra
Multiserver. Every time your application makes a call to Enhydra, the Director layer
intercepts the request and transparently routes it to one of several instances of
Multiserver. This elegant scheme equips every Enhydra application with load balancing
and fault tolerance, with no effort required from your programmers.
Lutris also supplies a pair of Windows DLLs that connect IIS applications to
Enhydra Director. This gives Windows Web developers an option that current J2EE servers
do not provide: the ability to blend native Windows Web and enterprise services with
server-side Java code. What's more, Enhydra lets you scale your application any way you
choose. In a pinch, you can boost a Windows Enhydra cluster by adding Linux or Solaris
servers. Your applications won't know the difference.
