Friday Jan 03, 2014

Getting Started with EL 3

EL 3 is one the APIs that has gone through a major overhaul in Java EE 7. In fact, EL is now finally a specification on its own right after long being an important API for JSTL, JSP, JSF and CDI. Most folks in the ecosystem are just beginning to realize the full significance of this. EL 3 opens up the possibility of using the power of a standard expression language in new and innovative ways in frameworks and applications much like the way Bean Validation 1.1 now utilizes EL. Just some of the changes in EL 3 includes a stand-alone API, powerful new operators, static field and method references, lambda support (essentially ahead of Java SE 8) and much, much more. Servlet 3.1 specification lead Shing Wai Chan handily demonstrates how some of the EL 3 features fit together in an excellent blog post. The code example calculates a standard deviation three different ways using various EL 3 features inside a Servlet. The blog post is really a great place to get started with learning EL 3. You can also check out Ed Burns and Kin-man Chung's JavaOne 2013 session on EL 3 via Parleys:

The slide deck for the session is available on the JavaOne content builder. It may be particularly interesting to relate the content of the slide deck back to Shing Wai Chan's blog entry.

Tuesday Aug 20, 2013

An Overview of EL 3

Although not mentioned often, EL 3 is one of the APIs that has gone through significant changes in Java EE 7. In fact, although EL has long been a very important part of APIs like JSTL, JSP, JSF, Facelets and CDI, with Java EE 7 EL got it's own JSR. Just some of the crucial changes in EL 3 include a standalone API, support for lambda expressions, static field and method access, improved collection processing and so on. Dan Woods did a pretty decent write-up of EL 3 on InfoQ. There's also the 15-minute EL 3 presentation by specification lead Kin-man Chung on the GlassFish videos YouTube channel:

You can also check out the official specification itself or try things out with the Java EE 7 SDK.

Wednesday Jun 20, 2012

EL 3.0 Public Review - JSR 341 and Java EE 7 Moving Along

Following closely on the lines of EL 3.0 Early Draft, the specification is now available for a Public Review. The JCP2 Process Document defines different stages of the specifications. This review period closes Jul 30, 2012.

Some of the main goals of the JSR are to separate ELContext into parsing and evaluation contexts, adding operators like equality, string concatenation, etc, and integration with CDI. The section A.7 of the specification highlights the difference between Early Draft and Public Review.

ALT_DESCR

Download the Public Review and and follow the updates at el-spec.java.net. For more information about EL 3.0 (JSR 341), check out the JSR project on java.net. The archives of EG discussion are available at jsr341-experts and you can subscribe to the users@el-spec and other aliases on the Mailing Lists page.

Monday Apr 23, 2012

Expression Language 3.0 / JSR 341 Early Draft Now Available

Expression Language (EL) has been a separate specification since JSP 2.0 but still part of the same JSR. The JSR 341 places EL in a separate specification. The Expert Group released Expression Language 3.0 Early Draft is now posted for a formal review.

Some of the main goals of the JSR are to separate ELContext into parsing and evaluation contexts, adding operators like equality, string concatenation, etc, and integration with CDI such as generating events before/during/after the expressions are evaluated.

ALT_DESCR

Download the Early Draft and and follow the updates at el-spec.java.net. For more information about EL 3.0 (JSR 341), check out the JSR project on java.net. The archives of EG discussion are available at jsr341-experts and you can subscribe to the users@el-spec and other aliases on the Mailing Lists page.