com.koushikdutta.quack.JavaMethodObject Maven / Gradle / Ivy

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The quickjs embeddable Javascript engine packaged for Java.
There is a newer version: 1.1.0
package com.koushikdutta.quack;

//import android.util.Log;

import java.lang.reflect.Array;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collections;

@SuppressWarnings({"unchecked", "rawtypes"})
public class JavaMethodObject implements QuackMethodObject {
    String target;
    QuackContext quackContext;
    Object originalThis;
    public JavaMethodObject(QuackContext quackContext, Object originalThis, String method) {
        this.quackContext = quackContext;
        this.originalThis = originalThis;
        this.target = method;
    }

    protected Object getThis(Object thiz, Method method) {
        return thiz;
    }

    protected Method[] getMethods(Object thiz) {
        Method[] methods = thiz.getClass().getMethods();
        if (!(thiz instanceof Class))
            return methods;

        ArrayList arr = new ArrayList<>();
        Collections.addAll(arr, methods);
        Collections.addAll(arr, ((Class)thiz).getMethods());
        return arr.toArray(new Method[0]);
    }

    @Override
    public Object callMethod(Object thiz, Object... args) {
        if (thiz == null || thiz instanceof JavaScriptObject)
            thiz = originalThis;
        if (thiz == null)
            throw new UnsupportedOperationException("can not call " + target);
        thiz = quackContext.coerceJavaScriptToJava(Object.class, thiz);

        Method[] thisMethods = getMethods(thiz);
        ArrayList argTypes = new ArrayList<>();
        for (Object arg: args) {
            if (arg == null)
                argTypes.add(null);
            else
                argTypes.add(arg.getClass());
        }
        Method best = QuackContext.javaObjectMethodCandidates.memoize(() -> {
            Method ret = null;
            int bestScore = Integer.MAX_VALUE;
            for (Method method: thisMethods) {
                if (!method.getName().equals(target)) {
                    QuackMethodName annotation = method.getAnnotation(QuackMethodName.class);
                    if (annotation == null || !annotation.name().equals(target))
                        continue;
                }
                // parameter count is most important
                int score = Math.abs(argTypes.size() - method.getParameterTypes().length) * 1000;
                // tiebreak by checking parameter types
                for (int i = 0; i < Math.min(method.getParameterTypes().length, argTypes.size()); i++) {
                    // check if the class is assignable or both parameters are numbers
                    Class argType = argTypes.get(i);
                    Class paramType = method.getParameterTypes()[i];
                    if (paramType == argType) {
                        score -= 4;
                    }
                    if (QuackContext.isNumberClass(paramType) && QuackContext.isNumberClass(argType)) {
                        score -= 3;
                    }
                    else if ((paramType == Long.class || paramType == long.class) && argType == String.class) {
                        score -= 2;
                    }
                    else if (argType == null || paramType.isAssignableFrom(argType)) {
                        score -= 1;
                    }
                }
                if (score < bestScore) {
                    bestScore = score;
                    ret = method;
                }
            }
            return ret;
        }, target, thisMethods, argTypes.toArray());

        if (best == null)
            throw new UnsupportedOperationException("can not call " + target);

        thiz = getThis(thiz, best);

        try {
            Method interfaceMethod = QuackContext.getInterfaceMethod(best);
            QuackMethodCoercion methodCoercion = quackContext.JavaScriptToJavaMethodCoercions.get(interfaceMethod);
            if (methodCoercion != null)
                return methodCoercion.invoke(interfaceMethod, thiz, args);

            int numParameters = best.getParameterTypes().length;
            if (best.isVarArgs())
                numParameters--;
            ArrayList