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/*
 * Copyright 2015-2016 the original author or authors.
 *
 * 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 org.nanoframework.commons.util;

import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.InvocationTargetException;

/**
 * 
 *
 * @author yanghe
 * @since 1.3.7
 */
public final class ReflectUtils {

    private ReflectUtils() {

    }

    /**
     * Attempts to create a class from a String.
     * @param  the class type
     * @param className the name of the class to create.
     * @return the class.  CANNOT be NULL.
     * @throws IllegalArgumentException if the className does not exist.
     */
    public static  Class loadClass(final String className) throws IllegalArgumentException {
        try {
            return convert(Class.forName(className));
        } catch (final ClassNotFoundException e) {
            throw new IllegalArgumentException(className + " class not found.");
        }
    }

    @SuppressWarnings("unchecked")
    public static  Class convert(final Class cls) {
        return (Class) cls;
    }

    /**
     * Creates a new instance of the given class by passing the given arguments
     * to the constructor.
     * @param  the newInstance type
     * @param className Name of class to be created.
     * @param args Constructor arguments.
     * @return New instance of given class.
     */
    public static  T newInstance(final String className, final Object... args) {
        return newInstance(ReflectUtils. loadClass(className), args);
    }

    /**
     * Creates a new instance of the given class by passing the given arguments
     * to the constructor.
     * @param  the newInstance type
     * @param clazz Class of instance to be created.
     * @param args Constructor arguments.
     * @return New instance of given class.
     */
    public static  T newInstance(final Class clazz, final Object... args) {
        final Class[] argClasses = new Class[args.length];
        for (int i = 0; i < args.length; i++) {
            argClasses[i] = args[i].getClass();
        }
        try {
            return clazz.getConstructor(argClasses).newInstance(args);
        } catch (final Exception e) {
            throw new IllegalArgumentException("Error creating new instance of " + clazz, e);
        }
    }

    /**
     * Gets the property descriptor for the named property on the given class.
     * @param clazz Class to which property belongs.
     * @param propertyName Name of property.
     * @return Property descriptor for given property or null if no property with given
     * name exists in given class.
     */
    public static PropertyDescriptor getPropertyDescriptor(final Class clazz, final String propertyName) {
        try {
            return getPropertyDescriptor(Introspector.getBeanInfo(clazz), propertyName);
        } catch (final IntrospectionException e) {
            throw new RuntimeException("Failed getting bean info for " + clazz, e);
        }
    }

    /**
     * Gets the property descriptor for the named property from the bean info describing
     * a particular class to which property belongs.
     * @param info Bean info describing class to which property belongs.
     * @param propertyName Name of property.
     * @return Property descriptor for given property or null if no property with given
     * name exists.
     */
    public static PropertyDescriptor getPropertyDescriptor(final BeanInfo info, final String propertyName) {
        for (int i = 0; i < info.getPropertyDescriptors().length; i++) {
            final PropertyDescriptor pd = info.getPropertyDescriptors()[i];
            if (pd.getName().equals(propertyName)) {
                return pd;
            }
        }
        return null;
    }

    /**
     * Sets the given property on the target JavaBean using bean instrospection.
     * @param propertyName Property to set.
     * @param value Property value to set.
     * @param target Target java bean on which to set property.
     */
    public static void setProperty(final String propertyName, final Object value, final Object target) {
        try {
            setProperty(propertyName, value, target, Introspector.getBeanInfo(target.getClass()));
        } catch (final IntrospectionException e) {
            throw new RuntimeException("Failed getting bean info on target JavaBean " + target, e);
        }
    }

    /**
     * Sets the given property on the target JavaBean using bean instrospection.
     * @param propertyName Property to set.
     * @param value Property value to set.
     * @param target Target JavaBean on which to set property.
     * @param info BeanInfo describing the target JavaBean.
     */
    public static void setProperty(final String propertyName, final Object value, final Object target, final BeanInfo info) {
        try {
            final PropertyDescriptor pd = getPropertyDescriptor(info, propertyName);
            pd.getWriteMethod().invoke(target, value);
        } catch (final InvocationTargetException e) {
            throw new RuntimeException("Error setting property " + propertyName, e.getCause());
        } catch (final Exception e) {
            throw new RuntimeException("Error setting property " + propertyName, e);
        }
    }
}