nashorn/src/jdk/nashorn/api/scripting/NashornScriptEngine.java - platform/libcore - Git at Google

 /*
  * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle in the LICENSE file that accompanied this code.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */

 package jdk.nashorn.api.scripting;

 import static jdk.nashorn.internal.runtime.ECMAErrors.referenceError;
 import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;

 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.Reader;
 import java.lang.reflect.Method;
 import java.net.URL;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
 import java.security.PrivilegedActionException;
 import java.security.PrivilegedExceptionAction;
 import javax.script.AbstractScriptEngine;
 import javax.script.Bindings;
 import javax.script.Compilable;
 import javax.script.CompiledScript;
 import javax.script.Invocable;
 import javax.script.ScriptContext;
 import javax.script.ScriptEngine;
 import javax.script.ScriptEngineFactory;
 import javax.script.ScriptException;
 import jdk.nashorn.internal.runtime.Context;
 import jdk.nashorn.internal.runtime.ErrorManager;
 import jdk.nashorn.internal.runtime.GlobalObject;
 import jdk.nashorn.internal.runtime.Property;
 import jdk.nashorn.internal.runtime.ScriptFunction;
 import jdk.nashorn.internal.runtime.ScriptObject;
 import jdk.nashorn.internal.runtime.ScriptRuntime;
 import jdk.nashorn.internal.runtime.Source;
 import jdk.nashorn.internal.runtime.linker.JavaAdapterFactory;
 import jdk.nashorn.internal.runtime.options.Options;

 /**
  * JSR-223 compliant script engine for Nashorn. Instances are not created directly, but rather returned through
  * {@link NashornScriptEngineFactory#getScriptEngine()}. Note that this engine implements the {@link Compilable} and
  * {@link Invocable} interfaces, allowing for efficient precompilation and repeated execution of scripts.
  * @see NashornScriptEngineFactory
  */

 public final class NashornScriptEngine extends AbstractScriptEngine implements Compilable, Invocable {

     private final ScriptEngineFactory factory;
     private final Context             nashornContext;
     private final ScriptObject        global;

     // default options passed to Nashorn Options object
     private static final String[] DEFAULT_OPTIONS = new String[] { "-scripting", "-af", "-doe" };

     NashornScriptEngine(final NashornScriptEngineFactory factory, final ClassLoader appLoader) {
         this(factory, DEFAULT_OPTIONS, appLoader);
     }

     NashornScriptEngine(final NashornScriptEngineFactory factory, final String[] args, final ClassLoader appLoader) {
         this.factory = factory;
         final Options options = new Options("nashorn");
         options.process(args);

         // throw ParseException on first error from script
         final ErrorManager errMgr = new Context.ThrowErrorManager();
         // create new Nashorn Context
         this.nashornContext = AccessController.doPrivileged(new PrivilegedAction<Context>() {
             @Override
             public Context run() {
                 try {
                     return new Context(options, errMgr, appLoader);
                 } catch (final RuntimeException e) {
                     if (Context.DEBUG) {
                         e.printStackTrace();
                     }
                     throw e;
                 }
             }
         });

         // create new global object
         this.global = createNashornGlobal();
         // set the default engine scope for the default context
         context.setBindings(new ScriptObjectMirror(global, global), ScriptContext.ENGINE_SCOPE);

         // evaluate engine initial script
         try {
             evalEngineScript();
         } catch (final ScriptException e) {
             if (Context.DEBUG) {
                 e.printStackTrace();
             }
             throw new RuntimeException(e);
         }
     }

     @Override
     public Object eval(final Reader reader, final ScriptContext ctxt) throws ScriptException {
         try {
             if (reader instanceof URLReader) {
                 final URL url = ((URLReader)reader).getURL();
                 return evalImpl(compileImpl(new Source(url.toString(), url), ctxt), ctxt);
             }
             return evalImpl(Source.readFully(reader), ctxt);
         } catch (final IOException e) {
             throw new ScriptException(e);
         }
     }

     @Override
     public Object eval(final String script, final ScriptContext ctxt) throws ScriptException {
         return evalImpl(script.toCharArray(), ctxt);
     }

     @Override
     public ScriptEngineFactory getFactory() {
         return factory;
     }

     @Override
     public Bindings createBindings() {
         final ScriptObject newGlobal = createNashornGlobal();
         return new ScriptObjectMirror(newGlobal, newGlobal);
     }

     // Compilable methods

     @Override
     public CompiledScript compile(final Reader reader) throws ScriptException {
         try {
             return asCompiledScript(compileImpl(Source.readFully(reader), context));
         } catch (final IOException e) {
             throw new ScriptException(e);
         }
     }

     @Override
     public CompiledScript compile(final String str) throws ScriptException {
         return asCompiledScript(compileImpl(str.toCharArray(), context));
     }

     // Invocable methods

     @Override
     public Object invokeFunction(final String name, final Object... args)
             throws ScriptException, NoSuchMethodException {
         return invokeImpl(null, name, args);
     }

     @Override
     public Object invokeMethod(final Object self, final String name, final Object... args)
             throws ScriptException, NoSuchMethodException {
         if (self == null) {
             throw new IllegalArgumentException("script object can not be null");
         }
         return invokeImpl(self, name, args);
     }

     private <T> T getInterfaceInner(final Object self, final Class<T> clazz) {
         final ScriptObject realSelf;
         final ScriptObject ctxtGlobal = getNashornGlobalFrom(context);
         if(self == null) {
             realSelf = ctxtGlobal;
         } else if (!(self instanceof ScriptObject)) {
             realSelf = (ScriptObject)ScriptObjectMirror.unwrap(self, ctxtGlobal);
         } else {
             realSelf = (ScriptObject)self;
         }
         try {
             final ScriptObject oldGlobal = getNashornGlobal();
             try {
                 if(oldGlobal != ctxtGlobal) {
                     setNashornGlobal(ctxtGlobal);
                 }

                 if (! isInterfaceImplemented(clazz, realSelf)) {
                     return null;
                 }
                 return clazz.cast(JavaAdapterFactory.getConstructor(realSelf.getClass(), clazz).invoke(realSelf));
             } finally {
                 if(oldGlobal != ctxtGlobal) {
                     setNashornGlobal(oldGlobal);
                 }
             }
         } catch(final RuntimeException|Error e) {
             throw e;
         } catch(final Throwable t) {
             throw new RuntimeException(t);
         }
     }

     @Override
     public <T> T getInterface(final Class<T> clazz) {
         return getInterfaceInner(null, clazz);
     }

     @Override
     public <T> T getInterface(final Object self, final Class<T> clazz) {
         if (self == null) {
             throw new IllegalArgumentException("script object can not be null");
         }
         return getInterfaceInner(self, clazz);
     }

     // These are called from the "engine.js" script

     /**
      * This hook is used to search js global variables exposed from Java code.
      *
      * @param self 'this' passed from the script
      * @param ctxt current ScriptContext in which name is searched
      * @param name name of the variable searched
      * @return the value of the named variable
      */
     public Object __noSuchProperty__(final Object self, final ScriptContext ctxt, final String name) {
         final int scope = ctxt.getAttributesScope(name);
         final ScriptObject ctxtGlobal = getNashornGlobalFrom(ctxt);
         if (scope != -1) {
             return ScriptObjectMirror.unwrap(ctxt.getAttribute(name, scope), ctxtGlobal);
         }

         if (self == UNDEFINED) {
             // scope access and so throw ReferenceError
             throw referenceError(ctxtGlobal, "not.defined", name);
         }

         return UNDEFINED;
     }

     private ScriptObject getNashornGlobalFrom(final ScriptContext ctxt) {
         final Bindings bindings = ctxt.getBindings(ScriptContext.ENGINE_SCOPE);
         if (bindings instanceof ScriptObjectMirror) {
              ScriptObject sobj = ((ScriptObjectMirror)bindings).getScriptObject();
              if (sobj instanceof GlobalObject) {
                  return sobj;
              }
         }

         // didn't find global object from context given - return the engine-wide global
         return global;
     }

     private ScriptObject createNashornGlobal() {
         final ScriptObject newGlobal = AccessController.doPrivileged(new PrivilegedAction<ScriptObject>() {
             @Override
             public ScriptObject run() {
                 try {
                     return nashornContext.newGlobal();
                 } catch (final RuntimeException e) {
                     if (Context.DEBUG) {
                         e.printStackTrace();
                     }
                     throw e;
                 }
             }
         });

         nashornContext.initGlobal(newGlobal);

         // current ScriptContext exposed as "context"
         newGlobal.addOwnProperty("context", Property.NOT_ENUMERABLE, UNDEFINED);
         // current ScriptEngine instance exposed as "engine". We added @SuppressWarnings("LeakingThisInConstructor") as
         // NetBeans identifies this assignment as such a leak - this is a false positive as we're setting this property
         // in the Global of a Context we just created - both the Context and the Global were just created and can not be
         // seen from another thread outside of this constructor.
         newGlobal.addOwnProperty("engine", Property.NOT_ENUMERABLE, this);
         // global script arguments with undefined value
         newGlobal.addOwnProperty("arguments", Property.NOT_ENUMERABLE, UNDEFINED);
         // file name default is null
         newGlobal.addOwnProperty(ScriptEngine.FILENAME, Property.NOT_ENUMERABLE, null);
         return newGlobal;
     }

     private void evalEngineScript() throws ScriptException {
         evalSupportScript("resources/engine.js", NashornException.ENGINE_SCRIPT_SOURCE_NAME);
     }

     private void evalSupportScript(final String script, final String name) throws ScriptException {
         try {
             final InputStream is = AccessController.doPrivileged(
                     new PrivilegedExceptionAction<InputStream>() {
                         @Override
                         public InputStream run() throws Exception {
                             final URL url = NashornScriptEngine.class.getResource(script);
                             return url.openStream();
                         }
                     });
             put(ScriptEngine.FILENAME, name);
             try (final InputStreamReader isr = new InputStreamReader(is)) {
                 eval(isr);
             }
         } catch (final PrivilegedActionException | IOException e) {
             throw new ScriptException(e);
         } finally {
             put(ScriptEngine.FILENAME, null);
         }
     }

     // scripts should see "context" and "engine" as variables
     private void setContextVariables(final ScriptContext ctxt) {
         ctxt.setAttribute("context", ctxt, ScriptContext.ENGINE_SCOPE);
         final ScriptObject ctxtGlobal = getNashornGlobalFrom(ctxt);
         ctxtGlobal.set("context", ctxt, false);
         Object args = ScriptObjectMirror.unwrap(ctxt.getAttribute("arguments"), ctxtGlobal);
         if (args == null || args == UNDEFINED) {
             args = ScriptRuntime.EMPTY_ARRAY;
         }
         // if no arguments passed, expose it
         args = ((GlobalObject)ctxtGlobal).wrapAsObject(args);
         ctxtGlobal.set("arguments", args, false);
     }

     private Object invokeImpl(final Object selfObject, final String name, final Object... args) throws ScriptException, NoSuchMethodException {
         final ScriptObject oldGlobal     = getNashornGlobal();
         final ScriptObject ctxtGlobal    = getNashornGlobalFrom(context);
         final boolean globalChanged = (oldGlobal != ctxtGlobal);

         Object self = globalChanged? ScriptObjectMirror.wrap(selfObject, oldGlobal) : selfObject;

         try {
             if (globalChanged) {
                 setNashornGlobal(ctxtGlobal);
             }

             ScriptObject sobj;
             Object       value = null;

             self = ScriptObjectMirror.unwrap(self, ctxtGlobal);

             // FIXME: should convert when self is not ScriptObject
             if (self instanceof ScriptObject) {
                 sobj = (ScriptObject)self;
                 value = sobj.get(name);
             } else if (self == null) {
                 self  = ctxtGlobal;
                 sobj  = ctxtGlobal;
                 value = sobj.get(name);
             }

             if (value instanceof ScriptFunction) {
                 final Object res;
                 try {
                     final Object[] modArgs = globalChanged? ScriptObjectMirror.wrapArray(args, oldGlobal) : args;
                     res = ScriptRuntime.checkAndApply((ScriptFunction)value, self, ScriptObjectMirror.unwrapArray(modArgs, ctxtGlobal));
                 } catch (final Exception e) {
                     throwAsScriptException(e);
                     throw new AssertionError("should not reach here");
                 }
                 return ScriptObjectMirror.translateUndefined(ScriptObjectMirror.wrap(res, ctxtGlobal));
             }

             throw new NoSuchMethodException(name);
         } finally {
             if (globalChanged) {
                 setNashornGlobal(oldGlobal);
             }
         }
     }

     private Object evalImpl(final char[] buf, final ScriptContext ctxt) throws ScriptException {
         return evalImpl(compileImpl(buf, ctxt), ctxt);
     }

     private Object evalImpl(final ScriptFunction script, final ScriptContext ctxt) throws ScriptException {
         if (script == null) {
             return null;
         }
         final ScriptObject oldGlobal = getNashornGlobal();
         final ScriptObject ctxtGlobal = getNashornGlobalFrom(ctxt);
         final boolean globalChanged = (oldGlobal != ctxtGlobal);
         try {
             if (globalChanged) {
                 setNashornGlobal(ctxtGlobal);
             }

             setContextVariables(ctxt);
             return ScriptObjectMirror.translateUndefined(ScriptObjectMirror.wrap(ScriptRuntime.apply(script, ctxtGlobal), ctxtGlobal));
         } catch (final Exception e) {
             throwAsScriptException(e);
             throw new AssertionError("should not reach here");
         } finally {
             if (globalChanged) {
                 setNashornGlobal(oldGlobal);
             }
         }
     }

     private static void throwAsScriptException(final Exception e) throws ScriptException {
         if (e instanceof ScriptException) {
             throw (ScriptException)e;
         } else if (e instanceof NashornException) {
             final NashornException ne = (NashornException)e;
             final ScriptException se = new ScriptException(
                 ne.getMessage(), ne.getFileName(),
                 ne.getLineNumber(), ne.getColumnNumber());
             se.initCause(e);
             throw se;
         } else if (e instanceof RuntimeException) {
             throw (RuntimeException)e;
         } else {
             // wrap any other exception as ScriptException
             throw new ScriptException(e);
         }
     }

     private CompiledScript asCompiledScript(final ScriptFunction script) {
         return new CompiledScript() {
             @Override
             public Object eval(final ScriptContext ctxt) throws ScriptException {
                 return evalImpl(script, ctxt);
             }
             @Override
             public ScriptEngine getEngine() {
                 return NashornScriptEngine.this;
             }
         };
     }

     private ScriptFunction compileImpl(final char[] buf, final ScriptContext ctxt) throws ScriptException {
         final Object val = ctxt.getAttribute(ScriptEngine.FILENAME);
         final String fileName = (val != null) ? val.toString() : "<eval>";
         return compileImpl(new Source(fileName, buf), ctxt);
     }

     private ScriptFunction compileImpl(final Source source, final ScriptContext ctxt) throws ScriptException {
         final ScriptObject oldGlobal = getNashornGlobal();
         final ScriptObject ctxtGlobal = getNashornGlobalFrom(ctxt);
         final boolean globalChanged = (oldGlobal != ctxtGlobal);
         try {
             if (globalChanged) {
                 setNashornGlobal(ctxtGlobal);
             }

             return nashornContext.compileScript(source, ctxtGlobal);
         } catch (final Exception e) {
             throwAsScriptException(e);
             throw new AssertionError("should not reach here");
         } finally {
             if (globalChanged) {
                 setNashornGlobal(oldGlobal);
             }
         }
     }

     private static boolean isInterfaceImplemented(final Class<?> iface, final ScriptObject sobj) {
         for (final Method method : iface.getMethods()) {
             // ignore methods of java.lang.Object class
             if (method.getDeclaringClass() == Object.class) {
                 continue;
             }

             Object obj = sobj.get(method.getName());
             if (! (obj instanceof ScriptFunction)) {
                 return false;
             }
         }
         return true;
     }

     // don't make this public!!
     static ScriptObject getNashornGlobal() {
         return Context.getGlobal();
     }

     static void setNashornGlobal(final ScriptObject newGlobal) {
         AccessController.doPrivileged(new PrivilegedAction<Void>() {
             @Override
             public Void run() {
                Context.setGlobal(newGlobal);
                return null;
             }
         });
     }
 }
	/*
	* Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package jdk.nashorn.api.scripting;

	import static jdk.nashorn.internal.runtime.ECMAErrors.referenceError;
	import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;

	import java.io.IOException;
	import java.io.InputStream;
	import java.io.InputStreamReader;
	import java.io.Reader;
	import java.lang.reflect.Method;
	import java.net.URL;
	import java.security.AccessController;
	import java.security.PrivilegedAction;
	import java.security.PrivilegedActionException;
	import java.security.PrivilegedExceptionAction;
	import javax.script.AbstractScriptEngine;
	import javax.script.Bindings;
	import javax.script.Compilable;
	import javax.script.CompiledScript;
	import javax.script.Invocable;
	import javax.script.ScriptContext;
	import javax.script.ScriptEngine;
	import javax.script.ScriptEngineFactory;
	import javax.script.ScriptException;
	import jdk.nashorn.internal.runtime.Context;
	import jdk.nashorn.internal.runtime.ErrorManager;
	import jdk.nashorn.internal.runtime.GlobalObject;
	import jdk.nashorn.internal.runtime.Property;
	import jdk.nashorn.internal.runtime.ScriptFunction;
	import jdk.nashorn.internal.runtime.ScriptObject;
	import jdk.nashorn.internal.runtime.ScriptRuntime;
	import jdk.nashorn.internal.runtime.Source;
	import jdk.nashorn.internal.runtime.linker.JavaAdapterFactory;
	import jdk.nashorn.internal.runtime.options.Options;

	/**
	* JSR-223 compliant script engine for Nashorn. Instances are not created directly, but rather returned through
	* {@link NashornScriptEngineFactory#getScriptEngine()}. Note that this engine implements the {@link Compilable} and
	* {@link Invocable} interfaces, allowing for efficient precompilation and repeated execution of scripts.
	* @see NashornScriptEngineFactory
	*/

	public final class NashornScriptEngine extends AbstractScriptEngine implements Compilable, Invocable {

	private final ScriptEngineFactory factory;
	private final Context nashornContext;
	private final ScriptObject global;

	// default options passed to Nashorn Options object
	private static final String[] DEFAULT_OPTIONS = new String[] { "-scripting", "-af", "-doe" };

	NashornScriptEngine(final NashornScriptEngineFactory factory, final ClassLoader appLoader) {
	this(factory, DEFAULT_OPTIONS, appLoader);
	}

	NashornScriptEngine(final NashornScriptEngineFactory factory, final String[] args, final ClassLoader appLoader) {
	this.factory = factory;
	final Options options = new Options("nashorn");
	options.process(args);

	// throw ParseException on first error from script
	final ErrorManager errMgr = new Context.ThrowErrorManager();
	// create new Nashorn Context
	this.nashornContext = AccessController.doPrivileged(new PrivilegedAction<Context>() {
	@Override
	public Context run() {
	try {
	return new Context(options, errMgr, appLoader);
	} catch (final RuntimeException e) {
	if (Context.DEBUG) {
	e.printStackTrace();
	}
	throw e;
	}
	}
	});

	// create new global object
	this.global = createNashornGlobal();
	// set the default engine scope for the default context
	context.setBindings(new ScriptObjectMirror(global, global), ScriptContext.ENGINE_SCOPE);

	// evaluate engine initial script
	try {
	evalEngineScript();
	} catch (final ScriptException e) {
	if (Context.DEBUG) {
	e.printStackTrace();
	}
	throw new RuntimeException(e);
	}
	}

	@Override
	public Object eval(final Reader reader, final ScriptContext ctxt) throws ScriptException {
	try {
	if (reader instanceof URLReader) {
	final URL url = ((URLReader)reader).getURL();
	return evalImpl(compileImpl(new Source(url.toString(), url), ctxt), ctxt);
	}
	return evalImpl(Source.readFully(reader), ctxt);
	} catch (final IOException e) {
	throw new ScriptException(e);
	}
	}

	@Override
	public Object eval(final String script, final ScriptContext ctxt) throws ScriptException {
	return evalImpl(script.toCharArray(), ctxt);
	}

	@Override
	public ScriptEngineFactory getFactory() {
	return factory;
	}

	@Override
	public Bindings createBindings() {
	final ScriptObject newGlobal = createNashornGlobal();
	return new ScriptObjectMirror(newGlobal, newGlobal);
	}

	// Compilable methods

	@Override
	public CompiledScript compile(final Reader reader) throws ScriptException {
	try {
	return asCompiledScript(compileImpl(Source.readFully(reader), context));
	} catch (final IOException e) {
	throw new ScriptException(e);
	}
	}

	@Override
	public CompiledScript compile(final String str) throws ScriptException {
	return asCompiledScript(compileImpl(str.toCharArray(), context));
	}

	// Invocable methods

	@Override
	public Object invokeFunction(final String name, final Object... args)
	throws ScriptException, NoSuchMethodException {
	return invokeImpl(null, name, args);
	}

	@Override
	public Object invokeMethod(final Object self, final String name, final Object... args)
	throws ScriptException, NoSuchMethodException {
	if (self == null) {
	throw new IllegalArgumentException("script object can not be null");
	}
	return invokeImpl(self, name, args);
	}

	private <T> T getInterfaceInner(final Object self, final Class<T> clazz) {
	final ScriptObject realSelf;
	final ScriptObject ctxtGlobal = getNashornGlobalFrom(context);
	if(self == null) {
	realSelf = ctxtGlobal;
	} else if (!(self instanceof ScriptObject)) {
	realSelf = (ScriptObject)ScriptObjectMirror.unwrap(self, ctxtGlobal);
	} else {
	realSelf = (ScriptObject)self;
	}
	try {
	final ScriptObject oldGlobal = getNashornGlobal();
	try {
	if(oldGlobal != ctxtGlobal) {
	setNashornGlobal(ctxtGlobal);
	}

	if (! isInterfaceImplemented(clazz, realSelf)) {
	return null;
	}
	return clazz.cast(JavaAdapterFactory.getConstructor(realSelf.getClass(), clazz).invoke(realSelf));
	} finally {
	if(oldGlobal != ctxtGlobal) {
	setNashornGlobal(oldGlobal);
	}
	}
	} catch(final RuntimeException\|Error e) {
	throw e;
	} catch(final Throwable t) {
	throw new RuntimeException(t);
	}
	}

	@Override
	public <T> T getInterface(final Class<T> clazz) {
	return getInterfaceInner(null, clazz);
	}

	@Override
	public <T> T getInterface(final Object self, final Class<T> clazz) {
	if (self == null) {
	throw new IllegalArgumentException("script object can not be null");
	}
	return getInterfaceInner(self, clazz);
	}

	// These are called from the "engine.js" script

	/**
	* This hook is used to search js global variables exposed from Java code.
	*
	* @param self 'this' passed from the script
	* @param ctxt current ScriptContext in which name is searched
	* @param name name of the variable searched
	* @return the value of the named variable
	*/
	public Object __noSuchProperty__(final Object self, final ScriptContext ctxt, final String name) {
	final int scope = ctxt.getAttributesScope(name);
	final ScriptObject ctxtGlobal = getNashornGlobalFrom(ctxt);
	if (scope != -1) {
	return ScriptObjectMirror.unwrap(ctxt.getAttribute(name, scope), ctxtGlobal);
	}

	if (self == UNDEFINED) {
	// scope access and so throw ReferenceError
	throw referenceError(ctxtGlobal, "not.defined", name);
	}

	return UNDEFINED;
	}

	private ScriptObject getNashornGlobalFrom(final ScriptContext ctxt) {
	final Bindings bindings = ctxt.getBindings(ScriptContext.ENGINE_SCOPE);
	if (bindings instanceof ScriptObjectMirror) {
	ScriptObject sobj = ((ScriptObjectMirror)bindings).getScriptObject();
	if (sobj instanceof GlobalObject) {
	return sobj;
	}
	}

	// didn't find global object from context given - return the engine-wide global
	return global;
	}

	private ScriptObject createNashornGlobal() {
	final ScriptObject newGlobal = AccessController.doPrivileged(new PrivilegedAction<ScriptObject>() {
	@Override
	public ScriptObject run() {
	try {
	return nashornContext.newGlobal();
	} catch (final RuntimeException e) {
	if (Context.DEBUG) {
	e.printStackTrace();
	}
	throw e;
	}
	}
	});

	nashornContext.initGlobal(newGlobal);

	// current ScriptContext exposed as "context"
	newGlobal.addOwnProperty("context", Property.NOT_ENUMERABLE, UNDEFINED);
	// current ScriptEngine instance exposed as "engine". We added @SuppressWarnings("LeakingThisInConstructor") as
	// NetBeans identifies this assignment as such a leak - this is a false positive as we're setting this property
	// in the Global of a Context we just created - both the Context and the Global were just created and can not be
	// seen from another thread outside of this constructor.
	newGlobal.addOwnProperty("engine", Property.NOT_ENUMERABLE, this);
	// global script arguments with undefined value
	newGlobal.addOwnProperty("arguments", Property.NOT_ENUMERABLE, UNDEFINED);
	// file name default is null
	newGlobal.addOwnProperty(ScriptEngine.FILENAME, Property.NOT_ENUMERABLE, null);
	return newGlobal;
	}

	private void evalEngineScript() throws ScriptException {
	evalSupportScript("resources/engine.js", NashornException.ENGINE_SCRIPT_SOURCE_NAME);
	}

	private void evalSupportScript(final String script, final String name) throws ScriptException {
	try {
	final InputStream is = AccessController.doPrivileged(
	new PrivilegedExceptionAction<InputStream>() {
	@Override
	public InputStream run() throws Exception {
	final URL url = NashornScriptEngine.class.getResource(script);
	return url.openStream();
	}
	});
	put(ScriptEngine.FILENAME, name);
	try (final InputStreamReader isr = new InputStreamReader(is)) {
	eval(isr);
	}
	} catch (final PrivilegedActionException \| IOException e) {
	throw new ScriptException(e);
	} finally {
	put(ScriptEngine.FILENAME, null);
	}
	}

	// scripts should see "context" and "engine" as variables
	private void setContextVariables(final ScriptContext ctxt) {
	ctxt.setAttribute("context", ctxt, ScriptContext.ENGINE_SCOPE);
	final ScriptObject ctxtGlobal = getNashornGlobalFrom(ctxt);
	ctxtGlobal.set("context", ctxt, false);
	Object args = ScriptObjectMirror.unwrap(ctxt.getAttribute("arguments"), ctxtGlobal);
	if (args == null \|\| args == UNDEFINED) {
	args = ScriptRuntime.EMPTY_ARRAY;
	}
	// if no arguments passed, expose it
	args = ((GlobalObject)ctxtGlobal).wrapAsObject(args);
	ctxtGlobal.set("arguments", args, false);
	}

	private Object invokeImpl(final Object selfObject, final String name, final Object... args) throws ScriptException, NoSuchMethodException {
	final ScriptObject oldGlobal = getNashornGlobal();
	final ScriptObject ctxtGlobal = getNashornGlobalFrom(context);
	final boolean globalChanged = (oldGlobal != ctxtGlobal);

	Object self = globalChanged? ScriptObjectMirror.wrap(selfObject, oldGlobal) : selfObject;

	try {
	if (globalChanged) {
	setNashornGlobal(ctxtGlobal);
	}

	ScriptObject sobj;
	Object value = null;

	self = ScriptObjectMirror.unwrap(self, ctxtGlobal);

	// FIXME: should convert when self is not ScriptObject
	if (self instanceof ScriptObject) {
	sobj = (ScriptObject)self;
	value = sobj.get(name);
	} else if (self == null) {
	self = ctxtGlobal;
	sobj = ctxtGlobal;
	value = sobj.get(name);
	}

	if (value instanceof ScriptFunction) {
	final Object res;
	try {
	final Object[] modArgs = globalChanged? ScriptObjectMirror.wrapArray(args, oldGlobal) : args;
	res = ScriptRuntime.checkAndApply((ScriptFunction)value, self, ScriptObjectMirror.unwrapArray(modArgs, ctxtGlobal));
	} catch (final Exception e) {
	throwAsScriptException(e);
	throw new AssertionError("should not reach here");
	}
	return ScriptObjectMirror.translateUndefined(ScriptObjectMirror.wrap(res, ctxtGlobal));
	}

	throw new NoSuchMethodException(name);
	} finally {
	if (globalChanged) {
	setNashornGlobal(oldGlobal);
	}
	}
	}

	private Object evalImpl(final char[] buf, final ScriptContext ctxt) throws ScriptException {
	return evalImpl(compileImpl(buf, ctxt), ctxt);
	}

	private Object evalImpl(final ScriptFunction script, final ScriptContext ctxt) throws ScriptException {
	if (script == null) {
	return null;
	}
	final ScriptObject oldGlobal = getNashornGlobal();
	final ScriptObject ctxtGlobal = getNashornGlobalFrom(ctxt);
	final boolean globalChanged = (oldGlobal != ctxtGlobal);
	try {
	if (globalChanged) {
	setNashornGlobal(ctxtGlobal);
	}

	setContextVariables(ctxt);
	return ScriptObjectMirror.translateUndefined(ScriptObjectMirror.wrap(ScriptRuntime.apply(script, ctxtGlobal), ctxtGlobal));
	} catch (final Exception e) {
	throwAsScriptException(e);
	throw new AssertionError("should not reach here");
	} finally {
	if (globalChanged) {
	setNashornGlobal(oldGlobal);
	}
	}
	}

	private static void throwAsScriptException(final Exception e) throws ScriptException {
	if (e instanceof ScriptException) {
	throw (ScriptException)e;
	} else if (e instanceof NashornException) {
	final NashornException ne = (NashornException)e;
	final ScriptException se = new ScriptException(
	ne.getMessage(), ne.getFileName(),
	ne.getLineNumber(), ne.getColumnNumber());
	se.initCause(e);
	throw se;
	} else if (e instanceof RuntimeException) {
	throw (RuntimeException)e;
	} else {
	// wrap any other exception as ScriptException
	throw new ScriptException(e);
	}
	}

	private CompiledScript asCompiledScript(final ScriptFunction script) {
	return new CompiledScript() {
	@Override
	public Object eval(final ScriptContext ctxt) throws ScriptException {
	return evalImpl(script, ctxt);
	}
	@Override
	public ScriptEngine getEngine() {
	return NashornScriptEngine.this;
	}
	};
	}

	private ScriptFunction compileImpl(final char[] buf, final ScriptContext ctxt) throws ScriptException {
	final Object val = ctxt.getAttribute(ScriptEngine.FILENAME);
	final String fileName = (val != null) ? val.toString() : "<eval>";
	return compileImpl(new Source(fileName, buf), ctxt);
	}

	private ScriptFunction compileImpl(final Source source, final ScriptContext ctxt) throws ScriptException {
	final ScriptObject oldGlobal = getNashornGlobal();
	final ScriptObject ctxtGlobal = getNashornGlobalFrom(ctxt);
	final boolean globalChanged = (oldGlobal != ctxtGlobal);
	try {
	if (globalChanged) {
	setNashornGlobal(ctxtGlobal);
	}

	return nashornContext.compileScript(source, ctxtGlobal);
	} catch (final Exception e) {
	throwAsScriptException(e);
	throw new AssertionError("should not reach here");
	} finally {
	if (globalChanged) {
	setNashornGlobal(oldGlobal);
	}
	}
	}

	private static boolean isInterfaceImplemented(final Class<?> iface, final ScriptObject sobj) {
	for (final Method method : iface.getMethods()) {
	// ignore methods of java.lang.Object class
	if (method.getDeclaringClass() == Object.class) {
	continue;
	}

	Object obj = sobj.get(method.getName());
	if (! (obj instanceof ScriptFunction)) {
	return false;
	}
	}
	return true;
	}

	// don't make this public!!
	static ScriptObject getNashornGlobal() {
	return Context.getGlobal();
	}

	static void setNashornGlobal(final ScriptObject newGlobal) {
	AccessController.doPrivileged(new PrivilegedAction<Void>() {
	@Override
	public Void run() {
	Context.setGlobal(newGlobal);
	return null;
	}
	});
	}
	}