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/**
 * Copyright (C) 2010 Mycila ([email protected])
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.mycila.guice.ext.injection;

import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.inject.internal.BytecodeGen;
import com.google.inject.internal.cglib.core.$CodeGenerationException;
import com.google.inject.internal.cglib.reflect.$FastMethod;

import java.lang.annotation.Annotation;
import java.lang.reflect.*;
import java.util.concurrent.ExecutionException;

/**
 * @author Mathieu Carbou ([email protected])
 */
public class MethodInvoker implements Member, AnnotatedElement {

    private static final LoadingCache INVOKERS = CacheBuilder.newBuilder()
        .weakKeys()
        .build(new CacheLoader() {
            @Override
            public MethodInvoker load(final Method method) throws Exception {
                int modifiers = method.getModifiers();
                if (!Modifier.isPrivate(modifiers) && !Modifier.isProtected(modifiers)) {
                    try {
                        final $FastMethod fastMethod = BytecodeGen.newFastClass(method.getDeclaringClass(), BytecodeGen.Visibility.forMember(method)).getMethod(method);
                        return new MethodInvoker(method) {
                            @Override
                            public Object invoke(Object target, Object... parameters) {
                                try {
                                    return fastMethod.invoke(target, parameters);
                                } catch (InvocationTargetException e) {
                                    throw MycilaGuiceException.toRuntime(e);
                                }
                            }
                        };
                    } catch ($CodeGenerationException e) {/* fall-through */}
                }
                if (!Modifier.isPublic(modifiers) || !Modifier.isPublic(method.getDeclaringClass().getModifiers())) {
                    method.setAccessible(true);
                }
                return new MethodInvoker(method);
            }
        });

    public final Method method;

    private MethodInvoker(Method method) {
        this.method = method;
    }

    public Object invoke(Object target, Object... parameters) {
        try {
            return method.invoke(target, parameters);
        } catch (IllegalAccessException e) {
            throw MycilaGuiceException.toRuntime(e);
        } catch (InvocationTargetException e) {
            throw MycilaGuiceException.toRuntime(e);
        }
    }

    public static MethodInvoker on(Method method) {
        try {
            return INVOKERS.get(method);
        } catch (ExecutionException e) {
            throw MycilaGuiceException.toRuntime(e);
        }
    }

    @Override
    public boolean isAnnotationPresent(Class annotationClass) {
        return Reflect.isAnnotationPresent(method, annotationClass);
    }

    @Override
    public Annotation[] getAnnotations() {
        return method.getAnnotations();
    }

    @Override
    public int getModifiers() {
        return method.getModifiers();
    }

    @Override
    public String getName() {
        return method.getName();
    }

    @Override
    public Class getDeclaringClass() {
        return method.getDeclaringClass();
    }

    @Override
    public Annotation[] getDeclaredAnnotations() {
        return method.getDeclaredAnnotations();
    }

    @Override
    public  T getAnnotation(Class annotationClass) {
        return method.getAnnotation(annotationClass);
    }

    @Override
    public boolean isSynthetic() {
        return method.isSynthetic();
    }

    @Override
    public String toString() {
        return method.toString();
    }
}