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package com.sun.grizzly.util;

import java.lang.reflect.Constructor;
import java.util.logging.Level;

/**
 * Class Cloner creates a clone of given object, 
 * which should implement interface Copyable
 * 
 * @author Alexey Stashok
 */
public class Cloner {
    /**
     * Method creates a clone of given object pattern
     * Pattern parameter should implement Copyable interface
     * 
     * @param pattern represents object, which will be cloned. Should implement Copyable
     * @return clone
     */
    public static  T clone(T pattern) {
        try {
            T copy = null;
            
            try {
                // Try default Constructor
                copy = (T) pattern.getClass().newInstance();
            } catch(InstantiationException e) {
                // If didn't succeed with default - try other public constructors
                Constructor[] constructors = pattern.getClass().getConstructors();
                if (constructors.length == 0) {
                    // if there are no public constructors - try others
                    constructors = pattern.getClass().getDeclaredConstructors();
                }
                
                for(Constructor constructor : constructors) {
                    constructor.setAccessible(true);
                    Object[] params = 
                            new Object[constructor.getParameterTypes().length];
                    
                    try {
                        copy = (T) constructor.newInstance(params);
                        break;
                    } catch(InstantiationException ee) {
                    }
                }
            }
            
            if (copy == null) {
                throw new InstantiationException("Could not create " +
                        "an instance of class: " + pattern.getClass().getName());
            }
            
            pattern.copyTo(copy);
            return copy;
        } catch (Exception e) {
            throw new RuntimeException("Error copying objects! " + e.getClass().getName() + ": " + e.getMessage());
        }
    }
}