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Rhino is an open-source implementation of JavaScript written entirely in Java. It is typically
embedded into Java applications to provide scripting to end users.
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.javascript.engine;
import java.io.IOException;
import java.io.Reader;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
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 javax.script.SimpleBindings;
import org.mozilla.javascript.Callable;
import org.mozilla.javascript.Context;
import org.mozilla.javascript.ContextFactory;
import org.mozilla.javascript.RhinoException;
import org.mozilla.javascript.Script;
import org.mozilla.javascript.Scriptable;
import org.mozilla.javascript.ScriptableObject;
/**
*
* This is the implementation of the standard ScriptEngine interface for Rhino.
*
*
* An instance of the Rhino ScriptEngine is fully self-contained. Bindings at the GLOBAL_SCOPE may
* be set, but there is nothing special about them -- if both global and ENGINE_SCOPE bindings are
* set then the "engine" bindings override the global ones.
*
*
* The Rhino engine is not thread safe. Rhino does no synchronization of ScriptEngine instances and
* no synchronization of Bindings instances. It is up to the caller to ensure that the ScriptEngine
* and all its Bindings are used by a single thread at a time.
*
*
* The Rhino script engine includes some top-level built-in functions. See the Builtins class for
* more documentation.
*
*
* The engine supports a few configuration parameters that may be set at the "engine scope". Both
* are numbers that may be set to a String or Number object.
*
*
* - javax.script.language_version: The version of the JavaScript language supported,
* which is an integer defined in the Context class. The default is the latest "ES6"
* version, defined as 200.
* - org.mozilla.javascript.optimization_level: The level of optimization Rhino performs
* on the generated bytecode. Default is 9, which is the most. Set to -1 to use interpreted
* mode.
*
*/
public class RhinoScriptEngine
extends AbstractScriptEngine
implements Compilable, Invocable {
/**
* Reserved key for the Rhino optimization level. Default is "9," for optimized and compiled code.
* Set this to "-1" to run Rhino in interpreted mode -- this is much much slower but the only
* option on platforms like Android that don't support class files.
*/
public static final String OPTIMIZATION_LEVEL = "org.mozilla.javascript.optimization_level";
static final int DEFAULT_LANGUAGE_VERSION = Context.VERSION_ES6;
private static final int DEFAULT_OPT = 9;
private static final boolean DEFAULT_DEBUG = true;
private static final String DEFAULT_FILENAME = "eval";
private static final CtxFactory ctxFactory = new CtxFactory();
private final RhinoScriptEngineFactory factory;
private final Builtins builtins;
private ScriptableObject topLevelScope = null;
RhinoScriptEngine(RhinoScriptEngineFactory factory) {
this.factory = factory;
this.builtins = new Builtins();
}
private Scriptable initScope(Context cx, ScriptContext sc) throws ScriptException {
configureContext(cx);
if (topLevelScope == null) {
topLevelScope = cx.initStandardObjects();
// We need to stash this away so that the built in functions can find
// this engine's specific stuff that they need to work.
topLevelScope.associateValue(Builtins.BUILTIN_KEY, builtins);
builtins.register(cx, topLevelScope, sc);
}
Scriptable engineScope = new BindingsObject(
sc.getBindings(ScriptContext.ENGINE_SCOPE));
engineScope.setParentScope(null);
engineScope.setPrototype(topLevelScope);
if (sc.getBindings(ScriptContext.GLOBAL_SCOPE) != null) {
Scriptable globalScope = new BindingsObject(
sc.getBindings(ScriptContext.GLOBAL_SCOPE));
globalScope.setParentScope(null);
globalScope.setPrototype(topLevelScope);
engineScope.setPrototype(globalScope);
}
return engineScope;
}
@Override
public Object eval(String script, ScriptContext context) throws ScriptException {
try (Context cx = ctxFactory.enterContext()) {
Scriptable scope = initScope(cx, context);
Object ret = cx.evaluateString(scope, script, getFilename(), 0, null);
return Context.jsToJava(ret, Object.class);
} catch (RhinoException re) {
throw new ScriptException(re.getMessage(), re.sourceName(), re.lineNumber(),
re.columnNumber());
}
}
@Override
public Object eval(Reader reader, ScriptContext context) throws ScriptException {
try (Context cx = ctxFactory.enterContext()) {
Scriptable scope = initScope(cx, context);
Object ret = cx.evaluateReader(scope, reader, getFilename(), 0, null);
return Context.jsToJava(ret, Object.class);
} catch (RhinoException re) {
throw new ScriptException(re.getMessage(), re.sourceName(), re.lineNumber(),
re.columnNumber());
} catch (IOException ioe) {
throw new ScriptException(ioe);
}
}
@Override
public CompiledScript compile(String script) throws ScriptException {
try (Context cx = ctxFactory.enterContext()) {
configureContext(cx);
Script s =
cx.compileString(script, getFilename(), 1, null);
return new RhinoCompiledScript(this, s);
} catch (RhinoException re) {
throw new ScriptException(re.getMessage(), re.sourceName(), re.lineNumber(),
re.columnNumber());
}
}
@Override
public CompiledScript compile(Reader script) throws ScriptException {
try (Context cx = ctxFactory.enterContext()) {
configureContext(cx);
Script s =
cx.compileReader(script, getFilename(), 1, null);
return new RhinoCompiledScript(this, s);
} catch (RhinoException re) {
throw new ScriptException(re.getMessage(), re.sourceName(), re.lineNumber(),
re.columnNumber());
} catch (IOException ioe) {
throw new ScriptException(ioe);
}
}
Object eval(Script script, ScriptContext sc) throws ScriptException {
try (Context cx = ctxFactory.enterContext()) {
Scriptable scope = initScope(cx, sc);
Object ret = script.exec(cx, scope);
return Context.jsToJava(ret, Object.class);
} catch (RhinoException re) {
throw new ScriptException(re.getMessage(), re.sourceName(), re.lineNumber(),
re.columnNumber());
}
}
@Override
public Object invokeFunction(String name, Object... args)
throws ScriptException, NoSuchMethodException {
return invokeMethod(null, name, args);
}
@Override
public Object invokeMethod(Object thiz, String name, Object... args)
throws ScriptException, NoSuchMethodException {
return invokeMethodRaw(thiz, name, Object.class, args);
}
Object invokeMethodRaw(Object thiz, String name, Class returnType, Object... args)
throws ScriptException, NoSuchMethodException {
try (Context cx = ctxFactory.enterContext()) {
Scriptable scope = initScope(cx, context);
Scriptable localThis;
if (thiz == null) {
localThis = scope;
} else {
localThis = Context.toObject(thiz, scope);
}
Object f = ScriptableObject.getProperty(localThis, name);
if (f == Scriptable.NOT_FOUND) {
throw new NoSuchMethodException(name);
}
if (!(f instanceof Callable)) {
throw new ScriptException("\"" + name + "\" is not a function");
}
Callable func = (Callable) f;
if (args != null) {
for (int i = 0; i < args.length; i++) {
args[i] = Context.javaToJS(args[i], scope);
}
}
Object ret = func.call(cx, scope, localThis, args);
if (returnType == Void.TYPE) {
return null;
}
return Context.jsToJava(ret, returnType);
} catch (RhinoException re) {
throw new ScriptException(re.getMessage(), re.sourceName(), re.lineNumber(),
re.columnNumber());
}
}
@SuppressWarnings("unchecked")
@Override
public T getInterface(Class clasz) {
if ((clasz == null) || !clasz.isInterface()) {
throw new IllegalArgumentException("Not an interface");
}
try (Context cx = ctxFactory.enterContext()) {
Scriptable scope = initScope(cx, context);
if (methodsMissing(scope, clasz)) {
return null;
}
} catch (ScriptException se) {
return null;
}
return (T) Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(),
new Class[]{clasz}, new RhinoInvocationHandler(this, null));
}
@SuppressWarnings("unchecked")
@Override
public T getInterface(Object thiz, Class clasz) {
if ((clasz == null) || !clasz.isInterface()) {
throw new IllegalArgumentException("Not an interface");
}
try (Context cx = ctxFactory.enterContext()) {
Scriptable scope = initScope(cx, context);
Scriptable thisObj = Context.toObject(thiz, scope);
if (methodsMissing(thisObj, clasz)) {
return null;
}
} catch (ScriptException se) {
return null;
}
return (T) Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(),
new Class[]{clasz}, new RhinoInvocationHandler(this, thiz));
}
@Override
public Bindings createBindings() {
return new SimpleBindings();
}
@Override
public ScriptEngineFactory getFactory() {
return factory;
}
private void configureContext(Context cx) throws ScriptException {
Object lv = get(ScriptEngine.LANGUAGE_VERSION);
if (lv != null) {
cx.setLanguageVersion(parseInteger(lv));
}
Object ol = get(OPTIMIZATION_LEVEL);
if (ol != null) {
cx.setOptimizationLevel(parseInteger(ol));
}
}
private static int parseInteger(Object v) throws ScriptException {
if (v instanceof String) {
try {
return Integer.parseInt((String) v);
} catch (NumberFormatException nfe) {
throw new ScriptException("Invalid number " + v);
}
} else if (v instanceof Integer) {
return ((Integer) v).intValue();
} else {
throw new ScriptException("Value must be a string or number");
}
}
private String getFilename() {
Object fn = get(ScriptEngine.FILENAME);
if (fn instanceof String) {
return (String) fn;
}
return DEFAULT_FILENAME;
}
private static boolean methodsMissing(Scriptable scope, Class clasz) {
for (Method m : clasz.getMethods()) {
if (m.getDeclaringClass() == Object.class) {
continue;
}
Object methodObj = ScriptableObject.getProperty(scope, m.getName());
if (!(methodObj instanceof Callable)) {
return true;
}
}
return false;
}
private static final class CtxFactory
extends ContextFactory {
@Override
protected boolean hasFeature(Context cx, int featureIndex) {
if (featureIndex == Context.FEATURE_INTEGER_WITHOUT_DECIMAL_PLACE) {
return true;
}
return super.hasFeature(cx, featureIndex);
}
@Override
protected void onContextCreated(Context cx) {
cx.setLanguageVersion(Context.VERSION_ES6);
cx.setOptimizationLevel(DEFAULT_OPT);
cx.setGeneratingDebug(DEFAULT_DEBUG);
}
}
}
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