BEGIN LICENSE BLOCK *****
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except in compliance with the License. You may obtain a copy of
the License at http://www.eclipse.org/legal/epl-v20.html
Software distributed under the License is distributed on an "AS
IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
implied. See the License for the specific language governing
rights and limitations under the License.
Copyright (C) 2001-2004 Jan Arne Petersen 
Copyright (C) 2002 Benoit Cerrina 
Copyright (C) 2002-2004 Anders Bengtsson 
Copyright (C) 2004-2008 Thomas E Enebo 
Copyright (C) 2004 Stefan Matthias Aust 
Copyright (C) 2005 Charles O Nutter 
Alternatively, the contents of this file may be used under the terms of
either of the GNU General Public License Version 2 or later (the "GPL"),
or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
in which case the provisions of the GPL or the LGPL are applicable instead
of those above. If you wish to allow use of your version of this file only
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use your version of this file under the terms of the EPL, indicate your
decision by deleting the provisions above and replace them with the notice
and other provisions required by the GPL or the LGPL. If you do not delete
the provisions above, a recipient may use your version of this file under
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 * Version: EPL 2.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Eclipse Public
 * License Version 2.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.eclipse.org/legal/epl-v20.html
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * Copyright (C) 2001-2004 Jan Arne Petersen <jpetersen@uni-bonn.de>
 * Copyright (C) 2002 Benoit Cerrina <b.cerrina@wanadoo.fr>
 * Copyright (C) 2002-2004 Anders Bengtsson <ndrsbngtssn@yahoo.se>
 * Copyright (C) 2004-2008 Thomas E Enebo <enebo@acm.org>
 * Copyright (C) 2004 Stefan Matthias Aust <sma@3plus4.de>
 * Copyright (C) 2005 Charles O Nutter <headius@headius.com>
 * 
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the EPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
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package org.jruby.javasupport.bsf;

import java.util.Arrays;
import java.util.List;
import java.util.Vector;

import org.apache.bsf.BSFDeclaredBean;
import org.apache.bsf.BSFException;
import org.apache.bsf.BSFManager;
import org.apache.bsf.util.BSFEngineImpl;
import org.apache.bsf.util.BSFFunctions;
import org.jruby.Ruby;
import org.jruby.RubyRuntimeAdapter;
import org.jruby.exceptions.JumpException;
import org.jruby.exceptions.RaiseException;
import org.jruby.javasupport.Java;
import org.jruby.javasupport.JavaEmbedUtils;
import org.jruby.javasupport.JavaObject;
import org.jruby.javasupport.JavaUtil;
import org.jruby.runtime.DynamicScope;
import org.jruby.runtime.GlobalVariable;
import org.jruby.runtime.IAccessor;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.builtin.IRubyObject;

An implementation of a JRuby BSF implementation.
/** 
 * An implementation of a JRuby BSF implementation.
 */
public class JRubyEngine extends BSFEngineImpl {
    private Ruby runtime;
    private RubyRuntimeAdapter evaler = JavaEmbedUtils.newRuntimeAdapter();

    @Override
    public Object apply(String file, int line, int col, Object funcBody, Vector paramNames, Vector args) {
        ThreadContext context = runtime.getCurrentContext();
        try {
            // Construct local variables based on parameter names passed in
            String[] names = new String[paramNames.size()];
            paramNames.toArray(names);
            context.preBsfApply(names);

            // Populate values for the parameter names
            DynamicScope scope = context.getCurrentScope();
            for (int i = 0, size = args.size(); i < size; i++) {
                scope.setValue(i, JavaEmbedUtils.javaToRuby(runtime, args.get(i)), 0);
            }

            return JavaEmbedUtils.rubyToJava(evaler.parse(runtime, funcBody.toString(), file, line).run());
        } catch (StackOverflowError soe) {
            throw context.runtime.newSystemStackError("stack level too deep", soe);
        } finally {
            context.postBsfApply();
        }
    }

    public Object eval(String file, int line, int col, Object expr) throws BSFException {
        try {
            return JavaEmbedUtils.rubyToJava(evaler.parse(runtime, expr.toString(), file, line).run());
        } catch (Exception excptn) {
            throw new BSFException(BSFException.REASON_EXECUTION_ERROR, "Exception", excptn);
        }
    }

    @Override
    public void exec(String file, int line, int col, Object expr) throws BSFException {
        try {
            evaler.parse(runtime, expr.toString(), file, line).run();
        } catch (Exception excptn) {
            throw new BSFException(BSFException.REASON_EXECUTION_ERROR, "Exception", excptn);
        }
    }

    public Object call(Object recv, String method, Object[] args) throws BSFException {
        try {
        	return JavaEmbedUtils.invokeMethod(runtime, recv, method, args, Object.class);
        } catch (Exception excptn) {
            throw new BSFException(BSFException.REASON_EXECUTION_ERROR, excptn.getMessage(), excptn);
        }
    }

    @Override
    public void initialize(BSFManager manager, String language, Vector someDeclaredBeans) throws BSFException {
        super.initialize(manager, language, someDeclaredBeans);

        runtime = JavaEmbedUtils.initialize(getClassPath(manager));

        for (int i = 0, size = someDeclaredBeans.size(); i < size; i++) {
            BSFDeclaredBean bean = (BSFDeclaredBean) someDeclaredBeans.elementAt(i);
            runtime.getGlobalVariables().define(
                    GlobalVariable.variableName(bean.name),
                    new BeanGlobalVariable(runtime, bean),
                    org.jruby.internal.runtime.GlobalVariable.Scope.GLOBAL);
        }

        runtime.getGlobalVariables().defineReadonly("$bsf", new FunctionsGlobalVariable(runtime, new BSFFunctions(manager, this)), org.jruby.internal.runtime.GlobalVariable.Scope.GLOBAL);
    }
    
    private List getClassPath(BSFManager manager) {
    	return Arrays.asList(manager.getClassPath().split(System.getProperty("path.separator")));
    }

    @Override
    public void declareBean(BSFDeclaredBean bean) throws BSFException {
        runtime.getGlobalVariables().define(
                GlobalVariable.variableName(bean.name),
                new BeanGlobalVariable(runtime, bean),
                org.jruby.internal.runtime.GlobalVariable.Scope.GLOBAL);
    }

    @Override
    public void undeclareBean(BSFDeclaredBean bean) throws BSFException {
        runtime.getGlobalVariables().set(GlobalVariable.variableName(bean.name), runtime.getNil());
    }

    public void handleException(BSFException bsfExcptn) {
        printException(runtime, (Exception) bsfExcptn.getTargetException());
    }

    
Prints out an error message.
Params:
exception – An Exception thrown by JRuby/**
     *
     * Prints out an error message.
     *
     * @param exception An Exception thrown by JRuby
     */
    private static void printException(Ruby runtime, Exception exception) {
    	if (exception instanceof RaiseException) runtime.printError(((RaiseException) exception).getException());
    }

    private static class BeanGlobalVariable implements IAccessor {
        private final Ruby runtime;
        private final BSFDeclaredBean bean;

        public BeanGlobalVariable(Ruby runtime, BSFDeclaredBean bean) {
            this.runtime = runtime;
            this.bean = bean;
        }

        public IRubyObject getValue() {
            IRubyObject result = JavaUtil.convertJavaToRuby(runtime, bean.bean, bean.type);
            
            return result instanceof JavaObject ? Java.wrap(runtime, result) : result;
        }

        public IRubyObject setValue(IRubyObject value) {
            bean.bean = value.toJava(Object.class);
            return value;
        }
    }

    private static class FunctionsGlobalVariable implements IAccessor {
        private final Ruby runtime;
        private final BSFFunctions functions;

        public FunctionsGlobalVariable(Ruby runtime, BSFFunctions functions) {
            this.runtime = runtime;
            this.functions = functions;
        }

        public IRubyObject getValue() {
            IRubyObject result = JavaUtil.convertJavaToRuby(runtime, functions, BSFFunctions.class);

            return result instanceof JavaObject ? Java.wrap(runtime, result) : result;
        }

        public IRubyObject setValue(IRubyObject value) {
            return value;
        }
    }

    
See Also:
terminate.terminate()/**
     * @see org.apache.bsf.BSFEngine#terminate()
     */
    @Override
    public void terminate() {
    	JavaEmbedUtils.terminate(runtime);
        runtime = null;
        super.terminate();
    }
}