package org.webslinger.bsf.groovy;

 import java.util.ArrayList;

 import java.util.concurrent.Callable;

 import org.webslinger.bsf.CompilingLanguageEngineImpl;

 import org.webslinger.bsf.LanguageEngineInfo;

 import groovy.lang.Closure;

 import org.codehaus.groovy.runtime.GroovyCategorySupport;

 public class GroovyEngine extends CompilingLanguageEngineImpl<Object, Class<? extends Object>> {

     public GroovyEngine() {

         compiler = new GroovyCompiler(this);

     }

     public LanguageEngineInfo getLanguageEngineInfo() {

         return GroovyInfo.INSTANCE;

     }

     public Object apply(Object body, final Object compiled, final Object[] args) throws Exception {

         Callable callable = new Callable() {

             public Object call() throws Exception {

                 return ((GroovyApply) compiled).apply(getManager(), args);

             }

         };

         return run(body, callable);

     }

     protected Object run(Object body, final Callable callable) throws Exception {

         String categoryNames = (String) getVFSDelegate().getAttribute(body, "groovy-categories");

         if (categoryNames == null) return callable.call();

         String[] names = categoryNames.split("[, ]");

         ArrayList<Class> categories = new ArrayList<Class>(names.length);

         ClassLoader loader = getManager().getClassLoader();

         for (String name : names) {

             categories.add(loader.loadClass(name));

         }

         final Exception[] thrownException = new Exception[] { null };

         final Object[] result = new Object[] { null };

         Closure closure = new Closure(this) {

             public Object call() {

                 try {

                     result[0] = callable.call();

                     return null;

                 } catch (Exception e) {

                     thrownException[0] = e;

                     return null;

                 }

             }

         };

         try {

             GroovyCategorySupport.use(categories, closure);

             return result[0];

         } finally {

             if (thrownException[0] != null) throw thrownException[0];

         }

     }

     public Object eval(Object body, Object compiled) throws Exception {

         throw new UnsupportedOperationException();

         //return ((GroovyCompiler.Eval) compiled).eval();

     }

     public void exec(Object body, Object compiled) throws Exception {

         throw new UnsupportedOperationException();

         //((GroovyCompiler.Exec) compiled).exec();

     }

 }