// ***********************************************************************
// Copyright (c) 2008 Charlie Poole
//
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// a copy of this software and associated documentation files (the
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// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
// ***********************************************************************

namespace NUnit.Framework.Constraints
{
    /// <summary>
    /// ReusableConstraint wraps a constraint expression after
    /// resolving it so that it can be reused consistently.
    /// </summary>
    public class ReusableConstraint : IResolveConstraint
    {
        private readonly Constraint constraint;

        /// <summary>
        /// Construct a ReusableConstraint from a constraint expression
        /// </summary>
        /// <param name="c">The expression to be resolved and reused</param>
        public ReusableConstraint(IResolveConstraint c)
        {
            this.constraint = c.Resolve();
        }

        /// <summary>
        /// Converts a constraint to a ReusableConstraint
        /// </summary>
        /// <param name="c">The constraint to be converted</param>
        /// <returns>A ReusableConstraint</returns>
        public static implicit operator ReusableConstraint(Constraint c)
        {
            return new ReusableConstraint(c);
        }

        /// <summary>
        /// Returns the string representation of the constraint.
        /// </summary>
        /// <returns>A string representing the constraint</returns>
        public override string ToString()
        {
            return constraint.ToString();
        }

        #region IResolveConstraint Members

        /// <summary>
        /// Resolves the ReusableConstraint by returning the constraint
        /// that it originally wrapped.
        /// </summary>
        /// <returns>A resolved constraint</returns>
        public Constraint Resolve()
        {
            return constraint;
        }

        #endregion
    }
}
