[ 源代码： el-api ]
软件包：libel-api-java（3.0.0-3）
Expression Language API
EL is a simple language designed to meet the needs of the presentation layer in Java web applications.
It features:
* A simple syntax restricted to the evaluation of expressions * Variables and nested properties * Relational, logical, arithmetic, conditional, and empty operators * Functions implemented as static methods on Java classes * Lenient semantics where appropriate default values and type conversions are provided to minimize exposing errors to end users