What is a Java content repository (Java content repository) (1)

Original address: http://www.onjava.com/pub/a/onjava/2006/10/04/what-is-java-content-repository.html? Page = 4
JSR-170 defines itself as an independent, standard way to access each other with the content repository. At the same time, it also makes its own definition of the content warehouse. It thinks that the content warehouse is an advanced information management system, which is an extension of the traditional data warehouse, it provides content services such as version control, full-text retrieval, access control, content classification, access control, and content event monitoring.

Java content repository API (JSR-170) attempts to establish a set of standard APIs to access the content repository. If you are not familiar with the Content Management System (CMS), you will be confused about what the content warehouse is. You can understand the content warehouse as a data storage application that stores text and binary data (images, Word documents, PDF, etc.).Program. A notable feature is that you don't have to worry about where your real data is stored. Is it a relational database? Is it a file system? Or XML? In addition to data storage and reading, most content repositories also provide more advanced features, such as Access Control, search, version control, and lock content.

For a period of time, different CMS systems developed by various manufacturers have emerged on the market. These systems are built on their respective content warehouses.
The problem arises. Each CMS developer provides their own APIs to access the content repository. This has plagued application developers because they need to learn the APIS provided by different developers and theirCodeIt is also bound to these specific APIs.

JSR-170 emerged to address this problem, providing a set of standard APIs to access any data warehouse. Through the JSR-170, you develop code that just needs to reference javax. JCR. * these classes and interfaces. It is applicable to any content repository compatible with JSR-170 specifications.

We will gradually learn about JSR-170 through an example.

Why JAVA content repository API

With the increase in the number of content warehouses of various manufacturers, people need a set of universal programming interfaces to use these content warehouses, which is what JSR-170 has to do. It provides a set of common programming interfaces to connect to the content warehouse. You can understand the JSR-170 as an API similar to JDBC so that you can develop your program without relying on any specific content repository implementation. You can directly use a content repository that supports JSR-170; or if some manufacturers of content Warehouse does not support JSR-170 can be provided by these manufacturers to complete the JSR-170 from the factory-specific content warehouse conversion.

The following figure describes the structure of an application system developed using a JSR-170. When the system is running, it can operate any of the content Warehouses 1, 2, and 3. In these content warehouse, only 2 is directly supporting the JSR-170, the remaining two need JSR-170 driver to interact with the application system. Note: Your application system does not have to worry about how your data is stored. 1 may have used relational databases for storage, while 2 may have used file systems. As for, it is even more avant-garde to use XML.

JSR-170 APIs offer different benefits to different people.

● Developers do not need to understand the factory's repository-specific APIs, as long as they are compatible with the JSR-170, they can access their repositories through the JSR-170.
● For companies that use CMS, there is no need to spend money to switch between content warehouses of different types of CMS.
● For CMS manufacturers, they do not need to develop their own content warehouses, but focus on developing CMS applications.