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https://issues.apache.org/jira/browse/JEXL-197?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Henri Biestro closed JEXL-197.
------------------------------
> Add annotations
> ---------------
>
> Key: JEXL-197
> URL: https://issues.apache.org/jira/browse/JEXL-197
> Project: Commons JEXL
> Issue Type: Improvement
> Reporter: Dmitri Blinov
> Assignee: Henri Biestro
> Priority: Major
> Fix For: 3.1
>
>
> Follow up from JEXL-194...
> As an implementation to the extension of statement executions in JEXL we
> could introduce the use of annotations to each statement or block in the
> script, i.e.
> {code}
> @synchronized(items) {for (x : items) ...}
> {code}
> Each statement block should be allowed to have only one annotation but it
> would be convenient to allow the syntax
> {code}
> @silent @lenient {null.tryMe()}
> {code}
> which should be syntaxically equivalent to:
> {code}
> @silent {@lenient {null.tryMe()}}
> {code}
> From the JexlEngine point of view, each annotation could be implemented in
> the form of Interceptor interface, for example
> {code}
> public interface Interceptor {
> public Object onExecute(JexlStatement block, String annotation, Object..
> args);
> }
> {code}
> The annotation syntax should allow for zero, one or more parameters. Those
> parameters should be evaluated before interceptor execution and submitted to
> the Interceptor.onExecute() method via args parameter.
> JexlEngine should be given a method to register annotation interceptor based
> on annotation name, and the one for default interceptor, which should be
> called before each statement execution as if @default annotation is declared
> in each statement in script.
> {code}
> @silent {@default {...}}
> {code}
> The JexlStatement is the proposed new interface to somehow identify the
> statement or block of code which may also provide some info about it's stack
> frame.
> {code}
> public interface JexlStatement {
> public Object interpret();
> // ..
> }
> {code}
> The JexlStatement.interpret() method should trigger the execution of the
> statement block, returning statement's result as its return value.
> In the absence of a matching interceptor corresponding to the annotation
> name, JexlEngine should simply ignore that, or write some diagnostic message
> in the log file.
> Such implementation could provide developers with excellent tool to add
> various checks and enhancements to scripting without pushing for new features
> that eventually would mess up the basic code. The JEXL-185 issue could also
> be dropped since tracing could be added easily via interceptors.
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