/src/NUnit/framework/Constraints/ReusableConstraint.cs

using System;



namespace NUnit.Framework.Constraints

{

    /// <summary>

    /// ReusableConstraint wraps a resolved constraint so that it

    /// may be saved and reused as needed.

    /// </summary>

    public class ReusableConstraint : IResolveConstraint

    {

        private Constraint constraint;



        /// <summary>

        /// Construct a ReusableConstraint

        /// </summary>

        /// <param name="c">The constraint or expression to be reused</param>

        public ReusableConstraint(IResolveConstraint c)

        {

            this.constraint = c.Resolve();

        }



        /// <summary>

        /// Conversion operator from a normal constraint to a ReusableConstraint.

        /// </summary>

        /// <param name="c">The original constraint to be wrapped as a ReusableConstraint</param>

        /// <returns></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

    }

}