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Rhino JavaScript runtime jar, excludes tools & JSR-223 Script Engine wrapper.
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/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* 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;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.HashSet;
/**
* Adapter to use JS function as implementation of Java interfaces with single method or multiple
* methods with the same signature.
*/
public class InterfaceAdapter {
private final Object proxyHelper;
/**
* Make glue object implementing interface cl that will call the supplied JS function when
* called. Only interfaces were all methods have the same signature is supported.
*
* @return The glue object or null if cl is not interface or has methods with
* different signatures.
*/
static Object create(Context cx, Class cl, ScriptableObject object) {
if (!cl.isInterface()) throw new IllegalArgumentException();
Scriptable topScope = ScriptRuntime.getTopCallScope(cx);
ClassCache cache = ClassCache.get(topScope);
InterfaceAdapter adapter;
adapter = (InterfaceAdapter) cache.getInterfaceAdapter(cl);
ContextFactory cf = cx.getFactory();
if (adapter == null) {
if (object instanceof Callable) {
Method[] methods = cl.getMethods();
// Check if interface can be implemented by a single function.
// We allow this if the interface has only one method or multiple
// methods with the same name (in which case they'd result in
// the same function to be invoked anyway).
HashSet functionalMethodNames = new HashSet<>();
HashSet defaultMethodNames = new HashSet<>();
for (Method method : methods) {
// there are multiple methods in the interface we inspect
// only abstract ones, they must all have the same name.
if (isFunctionalMethodCandidate(method)) {
functionalMethodNames.add(method.getName());
if (functionalMethodNames.size() > 1) {
break;
}
} else {
defaultMethodNames.add(method.getName());
}
}
boolean canConvert =
(functionalMethodNames.size() == 1)
|| (functionalMethodNames.isEmpty()
&& defaultMethodNames.size() == 1);
// There is no abstract method or there are multiple methods.
if (!canConvert) {
if (functionalMethodNames.isEmpty() && defaultMethodNames.isEmpty()) {
throw Context.reportRuntimeErrorById(
"msg.no.empty.interface.conversion", cl.getName());
} else {
throw Context.reportRuntimeErrorById(
"msg.no.function.interface.conversion", cl.getName());
}
}
}
adapter = new InterfaceAdapter(cf, cl);
cache.cacheInterfaceAdapter(cl, adapter);
}
return VMBridge.instance.newInterfaceProxy(
adapter.proxyHelper, cf, adapter, object, topScope);
}
/**
* We have to ignore java8 default methods and methods like 'equals', 'hashCode' and 'toString'
* as it occurs for example in the Comparator interface.
*
* @return true, if the function
*/
private static boolean isFunctionalMethodCandidate(Method method) {
if (method.getName().equals("equals")
|| method.getName().equals("hashCode")
|| method.getName().equals("toString")) {
// it should be safe to ignore them as there is also a special
// case for these methods in VMBridge_jdk18.newInterfaceProxy
return false;
} else {
return Modifier.isAbstract(method.getModifiers());
}
}
private InterfaceAdapter(ContextFactory cf, Class cl) {
this.proxyHelper = VMBridge.instance.getInterfaceProxyHelper(cf, new Class[] {cl});
}
public Object invoke(
ContextFactory cf,
final Object target,
final Scriptable topScope,
final Object thisObject,
final Method method,
final Object[] args) {
return cf.call(cx -> invokeImpl(cx, target, topScope, thisObject, method, args));
}
Object invokeImpl(
Context cx,
Object target,
Scriptable topScope,
Object thisObject,
Method method,
Object[] args) {
Callable function;
if (target instanceof Callable) {
function = (Callable) target;
} else {
Scriptable s = (Scriptable) target;
String methodName = method.getName();
Object value = ScriptableObject.getProperty(s, methodName);
if (value == Scriptable.NOT_FOUND) {
// We really should throw an error here, but for the sake of
// compatibility with JavaAdapter we silently ignore undefined
// methods.
Context.reportWarning(
ScriptRuntime.getMessageById(
"msg.undefined.function.interface", methodName));
Class resultType = method.getReturnType();
if (resultType == Void.TYPE) {
return null;
}
return Context.jsToJava(null, resultType);
}
if (!(value instanceof Callable)) {
throw Context.reportRuntimeErrorById("msg.not.function.interface", methodName);
}
function = (Callable) value;
}
WrapFactory wf = cx.getWrapFactory();
if (args == null) {
args = ScriptRuntime.emptyArgs;
} else {
for (int i = 0, N = args.length; i != N; ++i) {
Object arg = args[i];
// neutralize wrap factory java primitive wrap feature
if (!(arg instanceof String || arg instanceof Number || arg instanceof Boolean)) {
args[i] = wf.wrap(cx, topScope, arg, null);
}
}
}
Scriptable thisObj = wf.wrapAsJavaObject(cx, topScope, thisObject, null);
Object result = function.call(cx, topScope, thisObj, args);
Class javaResultType = method.getReturnType();
if (javaResultType == Void.TYPE) {
result = null;
} else {
result = Context.jsToJava(result, javaResultType);
}
return result;
}
}