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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;
  
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.

Returns:
The glue object or null if cl is not interface or has methods with different signatures.
 
     static Object create(Context cxClass<?> clScriptableObject 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 < lengthi++) {
                         if (!methodName.equals(methods[i].getName())) {
                             throw Context.reportRuntimeError1(
                                     "msg.no.function.interface.conversion",
                                     cl.getName());
                         }
                     }
                 }
             }
             adapter = new InterfaceAdapter(cfcl);
             cache.cacheInterfaceAdapter(cladapter);
         }
         return ..newInterfaceProxy(
             adapter.proxyHelpercfadapterobjecttopScope);
     }
 
     private InterfaceAdapter(ContextFactory cfClass<?> cl)
     {
         this.
             = ..getInterfaceProxyHelper(
                 cfnew 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(cxtargettopScopethisObjectmethodargs);
                 }
             };
         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(smethodName);
            if (value == .) {
                // 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 == .) {
                    return null;
                } else {
                    return Context.jsToJava(nullresultType);
                }
            }
            if (!(value instanceof Callable)) {
                throw Context.reportRuntimeError1(
                        "msg.not.function.interface",methodName);
            }
            function = (Callable)value;
        }
        WrapFactory wf = cx.getWrapFactory();
        if (args == null) {
            args = .;
        } else {
            for (int i = 0, N = args.lengthi != 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(cxtopScopeargnull);
                }
            }
        }
        Scriptable thisObj = wf.wrapAsJavaObject(cxtopScopethisObjectnull);
        Object result = function.call(cxtopScopethisObjargs);
        Class<?> javaResultType = method.getReturnType();
        if (javaResultType == .) {
            result = null;
        } else {
            result = Context.jsToJava(resultjavaResultType);
        }
        return result;
    }
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