Deconstructing Experience Services: the Java content repository

The Experience Services platform is built on top of a Java content repository (JCR). Day Software developed the JCR, CRX, that is in use by Adobe.

The term Java content repository can be used interchangebly for the Content Respository API for Java or for a software implementation of that API. The JCR is at heart an object database, with a hierarchical description of data. The API has standard methods to interact with an object database. It describes methods for importing and exporting data. It describes methods for searching the object database. Defined in the API, also, is data versioning.

Object databases (ODB) are interesting beasts. Most any type of data that is stored within a computer’s file system can be store in one. A Web site, with its whole directory and file structure, could be replicated in one. In addition, code can be stored and called inside an ODB. An ODB can be much more than the computer’s file system. Metadata can be defined for objects and the type of metadata stored can contain anything that the ODB can store.

My first introduction to an object database was with Userland Frontier back in the ’90s. The ODB contained scripts that ran a language called UserTalk. Website management capabilities were added to it and that is what I used it for. I learned the power of the practice of separating content from the code of the implementation. The information for the Website could be stored in the ODB not as HTML pages, but as content. The HTML was defined in separate templates, and the content and HTML code stayed distinct from one another until it came time to deploy. Then the pages would be created and placed online using FTP. A Web server was added to the ODB and Frontier became a content management system. Frontier had a lot of potential, but the company that developed it eventually stopped maintaining it.

The JCR at the core of Experience Services actualizes the potential that Frontier had, plus some. By itself, an object database does not do much. It is the parts that are hung from it that give it power.

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