#region License
/*
* Copyright 2002-2004 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.
*/
#endregion
#region Imports
using System;
#endregion
namespace Spring.Util{
/// <summary>
/// Utility class containing helper methods for object comparison.
/// </summary>
/// <author>Aleksandar Seovic</author>
public class CompareUtils
{
/// <summary>Compares two objects.</summary>
/// <param name="first">First object.</param>
/// <param name="second">Second object.</param>
/// <returns>
/// 0, if objects are equal;
/// less than zero, if the first object is smaller than the second one;
/// greater than zero, if the first object is greater than the second one.</returns>
public static int Compare(object first, object second)
{
// anything is greater than null, unless both operands are null
if (first == null)
{
return (second == null ? 0 : -1);
}
else if (second == null)
{
return 1;
}
if (!first.GetType().Equals(second.GetType()))
{
if (!CoerceTypes(ref first, ref second))
{
throw new ArgumentException("Cannot compare instances of ["
+ first.GetType().FullName
+ "] and ["
+ second.GetType().FullName
+ "] because they cannot be coerced to the same type.");
}
}
if (first is IComparable)
{
return ((IComparable)first).CompareTo(second);
}
else
{
throw new ArgumentException("Cannot compare instances of the type ["
+ first.GetType().FullName
+ "] because it doesn't implement IComparable");
}
}
private static bool CoerceTypes(ref object left, ref object right)
{
if (NumberUtils.IsNumber(left) && NumberUtils.IsNumber(right))
{
NumberUtils.CoerceTypes(ref right, ref left);
return true;
}
return false;
}
}
}
|