/* -*- 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;
/**
* 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 <tt>cl</tt> 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) {
Method[] methods = cl.getMethods();
if ( object instanceof Callable) {
// 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).
int length = methods.length;
if (length == 0) {
throw Context.reportRuntimeError1(
"msg.no.empty.interface.conversion", cl.getName());
}
if (length > 1) {
String methodName = methods[0].getName();
for (int i = 1; i < length; i++) {
if (!methodName.equals(methods[i].getName())) {
throw Context.reportRuntimeError1(
"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);
}
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)
{
ContextAction action = new ContextAction() {
public Object run(Context cx)
{
return invokeImpl(cx, target, topScope, thisObject, method, args);
}
};
return cf.call(action);
}
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 == ScriptableObject.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.getMessage1(
"msg.undefined.function.interface", methodName));
Class<?> resultType = method.getReturnType();
if (resultType == Void.TYPE) {
return null;
} else {
return Context.jsToJava(null, resultType);
}
}
if (!(value instanceof Callable)) {
throw Context.reportRuntimeError1(
"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;
}
}