Proposal for Jex Package

(0) Rationale

There is a number of expression language interpreters for Java. They all define different APIs, which makes it difficult to introduce new expression languages or new implementations of existing ones. The proposed Jex component provides a plug-in mechanism for expression language interpreters and common APIs for invocation of those.

(1) Scope of the Package

The org.apache.commons.jex package will define the following APIs:

Plug-in mechanism that allows introduction of new expression languages without changes to the org.apache.commons.jex package.
Expression evaluation: given an expression, compute the expression value
Modifying expression evaluation: given an expression describing a variable (or other left-side type of expression) and a new value, modify the value of that variable.
Iteration by expression: given an expression, produce an iterator
A pool of variables
Internationalization.
Jex will support both compiled and interpreted expression languages.
Out-of-the-box Jex will support at least two languages: JXPath (compiled) and Bexl (BeanUtils path language, interpreted).

(1.5) Interaction With Other Packages

Jex relies on

Java Development Kit (Version 1.2 or later)
BeanUtils (compile time, no run-time dependency)
JXPath (compile time, no run-time dependency)

No external configuration files are utilized.

(2) Initial Source of the Package

The original source of the component was donated by PLOTNIX, Inc (www.plotnix.com).

The proposed package names for the new component are

org.apache.commons.jex for the main API package
org.apache.commons.jex.bexl for integration with BeanUtils
org.apache.commons.jex.jxpath for integration with JXPath

(3) Required Jakarta-Commons Resources

SVN repository - New directory jex in the jakarta/commons SVN repository.
Mailing List - Discussions will take place on the general dev@commons.apache.org mailing list. To help list subscribers identify messages of interest, it is suggested that the message subject of messages about this component be prefixed with [jex].
Bugzilla - New component "jex" under the "Commons" product category, with appropriate version identifiers as needed.
Jyve FAQ - New category "commons-jex" (when available).

(4) Initial Committers

The initial committer on the JEX component shall be Dmitri Plotnikov.