package net.amoebaman.util;

import java.util.Arrays;

import org.apache.commons.lang.Validate;

/**
 * Represents a wrapper around an array class of an arbitrary reference type,
 * which properly implements "value" hash code and equality functions.
 * <p>
 * This class is intended for use as a key to a map.
 * </p>
 * @author Glen Husman
 * @param <E> The type of elements in the array.
 * @see Arrays
 */
public final class ArrayWrapper<E> {

    /**
     * Creates an array wrapper with some elements.
     * @param elements The elements of the array.
     */
    public ArrayWrapper(E... elements){
        setArray(elements);
    }

    private E[] _array;

    /**
     * Retrieves a reference to the wrapped array instance.
     * @return The array wrapped by this instance.
     */
    public E[] getArray(){
        return _array;
    }

    /**
     * Set this wrapper to wrap a new array instance.
     * @param array The new wrapped array.
     */
    public void setArray(E[] array){
        Validate.notNull(array, "The array must not be null.");
        _array = array;
    }

    /**
     * Determines if this object has a value equivalent to another object.
     * @see Arrays#equals(Object[], Object[])
     */
    @SuppressWarnings("rawtypes")
    @Override
    public boolean equals(Object other)
    {
        if (!(other instanceof ArrayWrapper))
        {
            return false;
        }
        return Arrays.equals(_array, ((ArrayWrapper)other)._array);
    }

    /**
     * Gets the hash code represented by this objects value.
     * @see Arrays#hashCode(Object[])
     * @return This object's hash code.
     */
    @Override
    public int hashCode()
    {
        return Arrays.hashCode(_array);
    }
}