The Client Applications layer contains the actual application, as the web browser, on the user's machine, that is, basically the presentation layer. Out of the box, Alfresco provides two client applications: Alfresco Explorer and Alfresco Share. Alfresco Explorer is a pure document management web application, and Alfresco Share is a web 2.0 application, that provides dynamic, collaborative support. In the next couple of chapters, we will talk about these two applications in detail. Along with these two applications, Alfresco provides support for CIFS, FTP, WebDAV, Microsoft office, and so on. Refer to the topic in Chapter 9, named Integrations, for more information on the different client applications that are integrated into Alfresco in order to leverage the services provided by Alfresco.

The Repository Services layer consists of Alfresco components and services. This new architecture provides a clear separation between the presentation tier and the repository tier. The Alfresco RESTful API provides access to its services via HTTP, which makes it accessible to other tools and applications. The Alfresco Surf platform enables you to build dynamic, REST-oriented web applications and collaborative web sites. More detailed information about Surf platforms are provided in Chapter 11. The SharePoint protocol offers greater choice for Microsoft users, by providing them with the first open source, fully-compatible SharePoint repository. Companies can leverage existing investments in Linux and Java, as well as Microsoft .NET connection software, to significantly reduce their SharePoint total cost of ownership and maximize their hardware and software investments. Chapter 11 describes SharePoint protocol in detail. The Content Management Interoperability Services (CMIS) specification defines a domain model and a set of API bindings that can be used by applications, to work with one or more Enterprise Content Management repositories or systems.

The Data Storage layer stores the data in a relational database and a file system.

The content in Alfresco is stored in persistent back-end systems such as a database and file system. There is a reason for using both database and a file system as content storage. Any content within Alfresco consists of two elements—the content itself and information about the content (metadata).

The actual content can be anything from simple documents (HTML, XML) to images, audio, and video. The actual content and its related versions are stored as binary files in the file system. Storing content in a file system has its own advantages. It allows a very large amount of content, random-access streaming, and options for different storage devices. It is important to note that Alfresco is agnostic with respect to the file system it utilizes. It is possible to configure Alfresco to use a vast diversity of file systems.

Alfresco uses Lucene—a popular open source search engine, to provide metadata searching, and full text search capabilities of the content. Apart from the actual binary content, Lucene's index files are also stored in the file system.

The content metadata consists of information that includes elements like:

The security settings are stored in the relational database.

The application server hosts the user interface and domain logic. It provides an abstraction and enables communication between the client and storage layers. In the case of Alfresco, the application server houses Alfresco applications (such as the Alfresco Explorer and Alfresco Share) and the Alfresco repository.

The Alfresco repository provides a set of reusable cross-cutting content management services such as content storage, query, versioning, and transformation, which may be utilized by one or more applications.

An Alfresco application provides a complete solution tailored for a specific area of content management such as document management and records management. The user interfaces for all of these applications are referred to as Alfresco Explorer and Alfresco Share. Alfresco Explorer is the JSF based client, which is highly customizable and configurable according to specific user requirements. The out of the box web client gives you lot of packaged functionality. With the web client management console, you can manage users, security, content, business rules, and so on. Additionally, Alfresco Share introduces a new, simplified, easy-to-use, and adopt knowledge worker UI. The current JSF client is still available and is unchanged.

There is no installation or configuration required for the Alfresco user interface. Any number of web browsers can connect to the application without prior client installation activities.

The out of box installation comes with Alfresco Share and the Alfresco Share web client, which you can use to connect to the Alfresco repository through web-based applications.

Apart from these applications, Alfresco's out of the box installation supports various client applications for accessing Alfresco content via Web Services or protocols such as FTP, WebDAV, and CIFS:

Web Services: Most of the ECM products, on the market store content, are in a proprietary format, which is like a black box. Alfresco's content is stored as per the JCR (Java Content Repository-JSR 170) open standards. Any JCR-compliant client application can read content that is stored in the Alfresco repository. This is one of the key selling points of Alfresco. An API is provided out of the box so that you can connect to the Alfresco repository from your applications, through web services or JCR integration.

Alfresco currently provides two types of product download options:

Both of these options have the same code base and features, and are completely open source. For both the options, you can use the Alfresco documentation (Wiki), community support (forums), and community-contributed add-on products. Alfresco Community Lab Network is free. Alfresco Enterprise Network requires a per-CPU license fee.

The Alfresco Community Labs Network is an unsupported product and is mainly designed for developers and technical enthusiasts in non-critical environments. Alfresco Community Lab is released early and often, and renders a daily build, while offering the latest functionality. It doesn't provide scalability or high availability certifications. I would recommend this for use as the research vehicle for new features, and as the platform for the Alfresco Community, and consider it as a test drive before you install the Enterprise edition.

If you are implementing Alfresco for a major corporation or a financial, insurance, government or healthcare organization, I would recommend that you go for Alfresco Enterprise Network support. The primary benefit is that with the support of Alfresco and its certified partners you will get a stable, reliable, certified, and supported application with warranty and indemnity. Your Alfresco version will be certified on all available stacks, such as Linux, Windows, MySQL, Oracle, and so on. You will also benefit from Alfresco support, which includes problem resolution, compatibility advice, migration advice, and upgrade support. For mission-critical applications, you will get 24 x 7 support from Alfresco experts.

Choosing an operating system to run Alfresco on will be based on various factors. For some companies it depends on in-house expertise. For example, if you have administrators and I.T staff who can easily manage business applications running on a Microsoft windows platform, then your choice could be to go with the Windows operating system. For some companies it is based on the integration requirements with existing systems.

If you do not have any preferences, I would recommend that you go with Linux operating system for production use. Linux source code is freely distributed. Tens of thousands of programmers have reviewed the source code to improve performance, eliminate bugs, and strengthen security. No other operating system has ever undergone this level of review. The key advantages of Linux are listed below:

The data access layer of Alfresco is implemented using an open source software component and ORM (Object Relational Mapping) tool called Hibernate. Hibernate abstracts the database layer and provides seamless integration between the Alfresco repository and any relational database.

If you have already chosen the Microsoft Windows operating system, then the natural choice for you would be MS SQL Server. If you already have a license for Oracle, then an Oracle database is the best choice for you. Alfresco also supports the PostgreSQL database.

If you do not have any preference, I recommend that you go with the MySQL database, which costs nothing if you go with the open source version. The MySQL database has become the world's most popular open source database because of its consistent, fast performance, high reliability, and easy usability. It's used in more than 10 million installations, ranging from large corporations to specialized embedded applications. MySQL runs on more than 20 platforms, including Linux, Windows, OS/X, HP-UX, AIX, and Netware, giving you the kind of flexibility that puts you in control.

Alfresco runs on any J2SE 5.0 complaint application server. Hence, there are no application server specific dependencies. However, it is important to make a choice of application server before moving into production.

Alfresco uses the Spring framework and not the Enterprise Java Beans (EJB) framework. This means that there is no dependency on JBoss or any other application server that provides EJB containers. Spring is an open source application framework for Java/JEE. The Alfresco repository uses the Spring Framework as the core foundation of its architecture. If you are developing a standalone application, then Apache Tomcat might be a good option. Tomcat powers numerous large-scale and mission-critical web applications across a diverse range of industries and organizations. It is the most widely-accepted web application server on the market.

On the other hand, you should consider using the JBoss application server, which has the highest market capture (> 35%) of J2EE-based application servers in the world. JBoss internally uses Tomcat, and hence you get the benefits of the Tomcat servlet engine as well.

Alfresco utilizes JBoss caching ability to distribute and maintain data caches, making it possible to build large-scale systems that outperform traditional Enterprise Content Management systems. Alfresco also utilizes the clustering, failover and load balancing facilities of the JBoss application server, in order to increase scalability. Alfresco's business process management features are powered by JBoss jBPM tool.

If you have already invested in JBoss, then Alfresco provides complementary industry-leading Enterprise Content Management technology to the JBoss enterprise middleware system suite.

You can go with a portal of your choice; if you already have an enterprise portal then you can integrate Alfresco with it. If you do not have a portal in place and you would like to leverage the portal framework, then you can consider using either the JBoss portal or the Liferay portal. Both of these are based on J2EE technology; both of them are open source and open standards based, and both of them have Alfresco's built-in support.

JBoss Portal provides an open source platform for hosting and serving a portal's web interface, publishing and managing its content, and customizing its experience. Whereas most packaged portal frameworks help enterprises to launch portals more quickly, only JBoss Portal delivers the benefits of a zero-cost, open source license combined with a flexible and scalable underlying platform.

Liferay is the most downloaded and popular open source portal with 40,000 downloads per month. It runs on top of any J2EE servlet, such as Tomcat, so a full installation of JBoss is not required. However, it can be run against most full application-servers out of the box including JBoss, JRun, BEA, WebLogic and Orion. It has full set of web service interfaces to the portal. Liferay supports 800+ portlets (products) and has wider adoption in the market.

You need to make the best choice of software to install Alfresco. If you do not have any specific requirements, you might consider a complete open source stack for production usage, and go with Alfresco Enterprise Edition on the Linux operating system with the MySQL database running on the JBoss application server with a Liferay Portal.

The examples in this book were created and tested with the following choice of Alfresco installation:

The default installation of Alfresco software requires installing the Windows enterprise version, Alfresco-Enterprise-<version>-Full-Setup.exe, downloaded from the SourceForge project location (http://sourceforge.net/project/showfiles.php?group_id=143373). Alfresco is hosting its own community download area, so you can also download this from http://www.Alfresco.com/products/ecm/enttrial/. Select the download package, and you will be asked for the user name and password of the Alfresco content community.

At the time of writing this book, the latest version was Alfresco Enterprise 3.0.1 and installer file Alfresco-Enterprise-3.0.1-Full-Setup.exe is approximately 350 MB in size.

This installer will install:

To install and run Alfresco, you need at least 500 MB disk space and at least 512 MB RAM on the desktop or server.

The following steps are a simple way of installing all of the software and components required to run Alfresco, through the installation wizard:

This section provides the installation pre-configured Tomcat bundle for Alfresco, which requires JDK to already be installed on your machine.

This section describes the installation of the Alfresco components.

Let's take a peek into the installation folder <Alfresco_installation_folder>, to look at the folders:

You can uninstall any program by double-clicking on the uninstall.exe file.

The options for starting and stopping Alfresco as a console application can be viewed by selecting Start | All Programs | Alfresco Enterprise. The options are as shown in the following screenshot:

The options there are discussed below:

Alternatively, you can always start, stop, and restart the Tomcat application server, and the MySQL database server, manually, by going to their respective folders. This gives more control to the user. However, the console option provides batch files to perform the start and stop procedures in a consolidated way, relieving the user of any unwanted errors.

You can also configure Alfresco as a Windows service in a standard Alfresco/Tomcat Installation. With the default installation, Alfresco is bundled as a web application that launches within Tomcat. To configure Alfresco to run as a Windows service, you need to set up Tomcat to run as a Windows service.

To configure Alfresco as a Windows service, carry out the following steps:

To uninstall the service, go to the <Alfresco_installation_folder>/tomcat/bin and enter the following command: service.bat uninstall Alfresco.

To edit your service settings, go to the <Alfresco_installation_folder>/tomcat/bin and enter the following command: tomcat5w.exe //ES//Alfresco

To start the service, locate the service named Alfresco Server in your Windows Service control panel, and start Alfresco from this control panel.