Building an Extensible Application with MEF, WPF, and MVVM

// 
// Copyright (c) 2004-2006 Jaroslaw Kowalski <jaak@jkowalski.net>
// 
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without 
// modification, are permitted provided that the following conditions 
// are met:
// 
// * Redistributions of source code must retain the above copyright notice, 
//   this list of conditions and the following disclaimer. 
// 
// * Redistributions in binary form must reproduce the above copyright notice,
//   this list of conditions and the following disclaimer in the documentation
//   and/or other materials provided with the distribution. 
// 
// * Neither the name of Jaroslaw Kowalski nor the names of its 
//   contributors may be used to endorse or promote products derived from this
//   software without specific prior written permission. 
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF 
// THE POSSIBILITY OF SUCH DAMAGE.
// 

using System;
using System.IO;
using System.Text;
using System.Collections;

namespace NLog.Conditions 
{
    /// <summary>
    /// A bunch of utility methods (mostly predicates) which can be used in
    /// condition expressions. Parially inspired by XPath 1.0.
    /// </summary>
    [ConditionMethods]
    public class ConditionMethods
    {
        /// <summary>
        /// Compares two objects for equality.
        /// </summary>
        /// <param name="o1">The first object</param>
        /// <param name="o2">The second object</param>
        /// <returns><b>true</b> when two objects are equal, <b>false</b> otherwise.</returns>
        [ConditionMethod("equals")]
        public static bool Equals2(object o1, object o2)
        {
            return o1.Equals(o2);
        }

        /// <summary>
        /// Determines whether the second string is a substring of the first one.
        /// </summary>
        /// <param name="s1">The first string</param>
        /// <param name="s2">The second string</param>
        /// <returns><b>true</b> when the second string is a substring of the first string, <b>false</b> otherwise.</returns>
        [ConditionMethod("contains")]
        public static bool Contains(string s1, string s2)
        {
            return s1.IndexOf(s2) >= 0;
        }

        /// <summary>
        /// Determines whether the second string is a prefix of the first one.
        /// </summary>
        /// <param name="s1">The first string</param>
        /// <param name="s2">The second string</param>
        /// <returns><b>true</b> when the second string is a prefix of the first string, <b>false</b> otherwise.</returns>
        [ConditionMethod("starts-with")]
        public static bool StartsWith(string s1, string s2)
        {
            return s1.StartsWith(s2);
        }

        /// <summary>
        /// Determines whether the second string is a suffix of the first one.
        /// </summary>
        /// <param name="s1">The first string</param>
        /// <param name="s2">The second string</param>
        /// <returns><b>true</b> when the second string is a prefix of the first string, <b>false</b> otherwise.</returns>
        [ConditionMethod("ends-with")]
        public static bool EndsWith(string s1, string s2)
        {
            return s1.EndsWith(s2);
        }

        /// <summary>
        /// Returns the length of a string.
        /// </summary>
        /// <param name="s">A string.</param>
        /// <returns>The length of a string.</returns>
        [ConditionMethod("length")]
        public static int Length(string s)
        {
            return s.Length;
        }
    }
}