multimap

49

因爲它幾乎聖誕節:)

////////////////////////////////////////////////////////////////////// 
// Algorithmia is (c) 2008 Solutions Design. All rights reserved. 
// http://www.sd.nl 
////////////////////////////////////////////////////////////////////// 
// COPYRIGHTS: 
// Copyright (c) 2008 Solutions Design. All rights reserved. 
// 
// The Algorithmia library sourcecode and its accompanying tools, tests and support code 
// are released under the following license: (BSD2) 
// ---------------------------------------------------------------------- 
// Redistribution and use in source and binary forms, with or without modification, 
// are permitted provided that the following conditions are met: 
// 
// 1) Redistributions of source code must retain the above copyright notice, this list of 
// conditions and the following disclaimer. 
// 2) 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. 
// 
// THIS SOFTWARE IS PROVIDED BY SOLUTIONS DESIGN ``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 SOLUTIONS DESIGN OR CONTRIBUTORS BE LIABLE FOR 
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// 
// The views and conclusions contained in the software and documentation are those of the authors 
// and should not be interpreted as representing official policies, either expressed or implied, 
// of Solutions Design. 
// 
////////////////////////////////////////////////////////////////////// 
// Contributers to the code: 
//  - Frans Bouma [FB] 
////////////////////////////////////////////////////////////////////// 
using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using SD.Tools.Algorithmia.UtilityClasses; 

namespace SD.Tools.Algorithmia.GeneralDataStructures 
{ 
    /// <summary> 
    /// Extension to the normal Dictionary. This class can store more than one value for every key. It keeps a HashSet for every Key value. 
    /// Calling Add with the same Key and multiple values will store each value under the same Key in the Dictionary. Obtaining the values 
    /// for a Key will return the HashSet with the Values of the Key. 
    /// </summary> 
    /// <typeparam name="TKey">The type of the key.</typeparam> 
    /// <typeparam name="TValue">The type of the value.</typeparam> 
    public class MultiValueDictionary<TKey, TValue> : Dictionary<TKey, HashSet<TValue>> 
    { 
     /// <summary> 
     /// Initializes a new instance of the <see cref="MultiValueDictionary&lt;TKey, TValue&gt;"/> class. 
     /// </summary> 
     public MultiValueDictionary() 
      : base() 
     { 
     } 


     /// <summary> 
     /// Adds the specified value under the specified key 
     /// </summary> 
     /// <param name="key">The key.</param> 
     /// <param name="value">The value.</param> 
     public void Add(TKey key, TValue value) 
     { 
      ArgumentVerifier.CantBeNull(key, "key"); 

      HashSet<TValue> container = null; 
      if(!this.TryGetValue(key, out container)) 
      { 
       container = new HashSet<TValue>(); 
       base.Add(key, container); 
      } 
      container.Add(value); 
     } 


     /// <summary> 
     /// Determines whether this dictionary contains the specified value for the specified key 
     /// </summary> 
     /// <param name="key">The key.</param> 
     /// <param name="value">The value.</param> 
     /// <returns>true if the value is stored for the specified key in this dictionary, false otherwise</returns> 
     public bool ContainsValue(TKey key, TValue value) 
     { 
      ArgumentVerifier.CantBeNull(key, "key"); 
      bool toReturn = false; 
      HashSet<TValue> values = null; 
      if(this.TryGetValue(key, out values)) 
      { 
       toReturn = values.Contains(value); 
      } 
      return toReturn; 
     } 


     /// <summary> 
     /// Removes the specified value for the specified key. It will leave the key in the dictionary. 
     /// </summary> 
     /// <param name="key">The key.</param> 
     /// <param name="value">The value.</param> 
     public void Remove(TKey key, TValue value) 
     { 
      ArgumentVerifier.CantBeNull(key, "key"); 

      HashSet<TValue> container = null; 
      if(this.TryGetValue(key, out container)) 
      { 
       container.Remove(value); 
       if(container.Count <= 0) 
       { 
        this.Remove(key); 
       } 
      } 
     } 


     /// <summary> 
     /// Merges the specified multivaluedictionary into this instance. 
     /// </summary> 
     /// <param name="toMergeWith">To merge with.</param> 
     public void Merge(MultiValueDictionary<TKey, TValue> toMergeWith) 
     { 
      if(toMergeWith==null) 
      { 
       return; 
      } 

      foreach(KeyValuePair<TKey, HashSet<TValue>> pair in toMergeWith) 
      { 
       foreach(TValue value in pair.Value) 
       { 
        this.Add(pair.Key, value); 
       } 
      } 
     } 


     /// <summary> 
     /// Gets the values for the key specified. This method is useful if you want to avoid an exception for key value retrieval and you can't use TryGetValue 
     /// (e.g. in lambdas) 
     /// </summary> 
     /// <param name="key">The key.</param> 
     /// <param name="returnEmptySet">if set to true and the key isn't found, an empty hashset is returned, otherwise, if the key isn't found, null is returned</param> 
     /// <returns> 
     /// This method will return null (or an empty set if returnEmptySet is true) if the key wasn't found, or 
     /// the values if key was found. 
     /// </returns> 
     public HashSet<TValue> GetValues(TKey key, bool returnEmptySet) 
     { 
      HashSet<TValue> toReturn = null; 
      if(!base.TryGetValue(key, out toReturn) && returnEmptySet) 
      { 
       toReturn = new HashSet<TValue>(); 
      } 
      return toReturn; 
     } 
    } 
}

來源

2008-12-19 10:32:32

+0

編輯：我misspoke - 我原本以爲這打破了LSP（它*可能*） - 但我認爲它沒關係，因爲它沒有隱藏任何基類方法，它們仍應按預期工作。向下投票恢復:) – mhand 2017-12-01 20:48:15