BsonMinKey.cs

/* Copyright 2010-present MongoDB Inc.
*
* 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.
*/

using System;
using MongoDB.Shared;

namespace MongoDB.Bson
{
    /// <summary>
    /// Represents the BSON MinKey value.
    /// </summary>
    public class BsonMinKey : BsonValue, IComparable<BsonMinKey>, IEquatable<BsonMinKey>
    {
        // private static fields
        private static BsonMinKey __value = new BsonMinKey();

        // constructors
        // private so only the singleton instance can be created
        private BsonMinKey()
        {
        }

        // public operators
        /// <summary>
        /// Compares two BsonMinKey values.
        /// </summary>
        /// <param name="lhs">The first BsonMinKey.</param>
        /// <param name="rhs">The other BsonMinKey.</param>
        /// <returns>True if the two BsonMinKey values are not equal according to ==.</returns>
        public static bool operator !=(BsonMinKey lhs, BsonMinKey rhs)
        {
            return !(lhs == rhs);
        }

        /// <summary>
        /// Compares two BsonMinKey values.
        /// </summary>
        /// <param name="lhs">The first BsonMinKey.</param>
        /// <param name="rhs">The other BsonMinKey.</param>
        /// <returns>True if the two BsonMinKey values are equal according to ==.</returns>
        public static bool operator ==(BsonMinKey lhs, BsonMinKey rhs)
        {
            if (object.ReferenceEquals(lhs, null)) { return object.ReferenceEquals(rhs, null); }
            return lhs.Equals(rhs);
        }

        // public static properties
        /// <summary>
        /// Gets the singleton instance of BsonMinKey.
        /// </summary>
        public static BsonMinKey Value { get { return __value; } }

        // public properties
        /// <summary>
        /// Gets the BsonType of this BsonValue.
        /// </summary>
        public override BsonType BsonType
        {
            get { return BsonType.MinKey; }
        }

        // public methods
        /// <summary>
        /// Compares this BsonMinKey to another BsonMinKey.
        /// </summary>
        /// <param name="other">The other BsonMinKey.</param>
        /// <returns>A 32-bit signed integer that indicates whether this BsonMinKey is less than, equal to, or greather than the other.</returns>
        public int CompareTo(BsonMinKey other)
        {
            if (other == null) { return 1; }
            return 0; // it's a singleton
        }

        /// <summary>
        /// Compares the BsonMinKey to another BsonValue.
        /// </summary>
        /// <param name="other">The other BsonValue.</param>
        /// <returns>A 32-bit signed integer that indicates whether this BsonMinKey is less than, equal to, or greather than the other BsonValue.</returns>
        public override int CompareTo(BsonValue other)
        {
            if (other == null) { return 1; }
            if (other is BsonMinKey) { return 0; }
            return -1;
        }

        /// <summary>
        /// Compares this BsonMinKey to another BsonMinKey.
        /// </summary>
        /// <param name="rhs">The other BsonMinKey.</param>
        /// <returns>True if the two BsonMinKey values are equal.</returns>
        public bool Equals(BsonMinKey rhs)
        {
            if (object.ReferenceEquals(rhs, null) || GetType() != rhs.GetType()) { return false; }
            return true; // it's a singleton
        }

        /// <summary>
        /// Compares this BsonMinKey to another object.
        /// </summary>
        /// <param name="obj">The other object.</param>
        /// <returns>True if the other object is a BsonMinKey and equal to this one.</returns>
        public override bool Equals(object obj)
        {
            return Equals(obj as BsonMinKey); // works even if obj is null or of a different type
        }

        /// <summary>
        /// Gets the hash code.
        /// </summary>
        /// <returns>The hash code.</returns>
        public override int GetHashCode()
        {
            return Hasher.GetHashCode(BsonType);
        }

        /// <summary>
        /// Returns a string representation of the value.
        /// </summary>
        /// <returns>A string representation of the value.</returns>
        public override string ToString()
        {
            return "BsonMinKey";
        }
    }
}