/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * 
 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
 * 
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License. You can obtain
 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
 * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 * 
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
 * Sun designates this particular file as subject to the "Classpath" exception
 * as provided by Sun in the GPL Version 2 section of the License file that
 * accompanied this code.  If applicable, add the following below the License
 * Header, with the fields enclosed by brackets [] replaced by your own
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 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
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 */
package com.sun.appserv.management.util.misc;

import java.lang.reflect.Array;

/**
	Provides:
	- utility to check for equality
 */
public final class ArrayUtil
{
		private
	ArrayUtil( )
	{
		// disallow instantiation
	}
	
		public static boolean
	arraysEqual( final Object array1, final Object array2 )
	{
		boolean	equal	= array1 == array2;
		
		if ( equal )
		{
			// same object or both null
			return( true );
		}
		else if ( array1 == null || array2 == null)
		{
			return( false );
		}
		

		if ( array1.getClass() == array2.getClass() &&
			ClassUtil.objectIsArray( array1 ) &&
			Array.getLength( array1 ) == Array.getLength( array2 ) )
		{
			equal	= true;
			final int	length	= Array.getLength( array1 );
			
			for( int i = 0; i < length; ++ i )
			{
				final Object	a1	= Array.get( array1, i );
				final Object	a2	= Array.get( array2, i );
				
				if ( a1 != a2)
				{
					if ( a1 == null || a2 == null )
					{
						equal	= false;
					}
					else if ( ClassUtil.objectIsArray( a1 )  )
					{
						if ( ! arraysEqual( a1, a2 ) )
						{
							equal	= false;
						}
					}
				}

				if ( ! equal )
					break;
			}
		}
		
		return( equal );
	}

		public static boolean
	arrayContainsNulls( final Object[] array )
	{
		boolean	containsNulls	= false;
		
		for( int i = 0; i < array.length; ++i )
		{
			if ( array[ i ] == null )
			{
				containsNulls	= true;
				break;
			}
		}
		
		return( containsNulls );
	}
	

        public static <T> T[]
    newArray( final Class<T> theClass, int numItems )
    {
        return (T[])( Array.newInstance( theClass, numItems ) );
    }
	
	/**
		Create a new array from the original.
		
		@param items		the original array
		@param startIndex	index of the first item
		@param numItems		
		@return an array of the same type, containing numItems items
	 */
		public static <T> T[]
	newArray(
		final T[]	items,
		final int	startIndex,
		final int	numItems )
	{
		final Class<T>	theClass	= TypeCast.asClass( items.getClass().getComponentType() );
		
		final T[]	result	= newArray( theClass, numItems );
		System.arraycopy( items, startIndex, result, 0, numItems );
		
		return( result );
	}
	
	/**
		Create a new array consisting of originals and new.
		
		@param items1		1st array
		@param items2		2nd array
		@return an array of the same type as items1, its elements first
	 */
		public static <T> T[]
	newArray(
		final T[]	items1,
		final T[]	items2)
	{
		final Class<T> class1	= TypeCast.asClass( items1.getClass().getComponentType() );
		final Class<T> class2	= TypeCast.asClass( items2.getClass().getComponentType() );
		
		if ( ! class1.isAssignableFrom( class2 ) )
		{
			throw new IllegalArgumentException();
		}
		
		final int	length1	= Array.getLength( items1 );
		final int	length2	= Array.getLength( items2 );
		final T[]	result	= newArray( class1, length1 + length2 );
		System.arraycopy( items1, 0, result, 0, length1 );
		System.arraycopy( items2, 0, result, length1, length2 );
		
		return( result );
	}
	
	/**
		Create a new array consisting of an original array, and a single new item.
		
		@param items		an array
		@param item		an item to append
		@return an array of the same type as items1, its elements first
	 */
		public static <T> T[]
	newArray(
		final T[]	items,
		final T	item)
	{
		final Class<T>	theClass	= TypeCast.asClass( items.getClass().getComponentType() );
		final T[]	result	= newArray( theClass, items.length + 1 );
		System.arraycopy( items, 0, result, 0, items.length );
		
		result[ result.length - 1 ]	= item;
		return( result );
	}
}