MethodReference.java

package com.unicus.reflect;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import jdk.internal.org.objectweb.asm.Type;

/**
 * @author Caleb Whiting
 */
public class MethodReference {

    private final String key;
    private final String owner;
    private final String name;
    private final String signature;
    private final int expectedParameters;
    private final int opaquePredicate;

    private Method value;

    public MethodReference(String key, String owner, String name, String signature, int expectedParameters, int opaquePredicate) {
        this.key = key;
        this.owner = owner;
        this.name = name;
        this.signature = signature;
        this.expectedParameters = expectedParameters;
        this.opaquePredicate = opaquePredicate;
    }

    public String getKey() {
        return key;
    }

    public String getOwner() {
        return owner;
    }

    public String getName() {
        return name;
    }

    public String getSignature() {
        return signature;
    }

    public int getExpectedParameters() {
        return expectedParameters;
    }

    public int getOpaquePredicate() {
        return opaquePredicate;
    }

    public Object invoke(Object reference, Object... arguments) {
        try {
            if (arguments.length != getExpectedParameters()) {
                Object[] args = new Object[getExpectedParameters()];
                System.arraycopy(arguments, 0, args, 0, arguments.length);
                args[args.length - 1] = getOpaquePredicate();
                arguments = args;
            }
            return get().invoke(reference, arguments);
        } catch (IllegalAccessException | InvocationTargetException e) {
            throw new RuntimeException(e);
        }
    }

    public Method get() {
        if (value != null) {
            return value;
        }
        Class owner = ReflectContext.get().loadClass(getOwner());
        Type type = Type.getType(getSignature());
        for (Method method : owner.getMethods()) {
            if (method.getName().equals(getName()) && Type.getType(method).equals(type)) {
                method.setAccessible(true);
                return value = method;
            }
        }
        throw new RuntimeException("Couldn't find method " + getOwner() + "." + getName() + " '" + getSignature() + "'");
    }

}