| /* |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 System.Collections; |
| |
| namespace Apache.Qpid.Collections |
| { |
| public class LinkedHashtable : IDictionary |
| { |
| /// <summary> |
| /// Maps from key to LinkedDictionaryEntry |
| /// </summary> |
| private Hashtable _indexedValues = new Hashtable(); |
| |
| private LinkedDictionaryEntry _head; |
| |
| private LinkedDictionaryEntry _tail; |
| |
| private class LinkedDictionaryEntry |
| { |
| public LinkedDictionaryEntry _previous; |
| public LinkedDictionaryEntry _next; |
| internal DictionaryEntry _entry; |
| |
| public LinkedDictionaryEntry(object key, object value) |
| { |
| _entry = new DictionaryEntry(key, value); |
| } |
| } |
| |
| public object this[object key] |
| { |
| get |
| { |
| LinkedDictionaryEntry entry = (LinkedDictionaryEntry)_indexedValues[key]; |
| if (entry == null) |
| { |
| return null; // key not found |
| } |
| else |
| { |
| return entry._entry.Value; |
| } |
| } |
| |
| set |
| { |
| LinkedDictionaryEntry entry = (LinkedDictionaryEntry)_indexedValues[key]; |
| if (entry == null) |
| { |
| Add(key, value); |
| } |
| else |
| { |
| entry._entry.Value = value; |
| } |
| } |
| } |
| |
| /// <summary> |
| /// Collect keys in linked order. |
| /// </summary> |
| public ICollection Keys |
| { |
| get |
| { |
| IList result = new ArrayList(); |
| foreach (DictionaryEntry entry in this) |
| { |
| result.Add(entry.Key); |
| } |
| return result; |
| } |
| } |
| |
| /// <summary> |
| /// Collect values in linked order. |
| /// </summary> |
| public ICollection Values |
| { |
| get |
| { |
| IList result = new ArrayList(); |
| foreach (DictionaryEntry entry in this) |
| { |
| result.Add(entry.Value); |
| } |
| return result; |
| } |
| } |
| |
| public bool IsReadOnly |
| { |
| get { return _indexedValues.IsReadOnly; } |
| } |
| |
| public bool IsFixedSize |
| { |
| get { return _indexedValues.IsFixedSize; } |
| } |
| |
| public bool Contains(object key) |
| { |
| return _indexedValues.Contains(key); |
| } |
| |
| public void Add(object key, object value) |
| { |
| if (key == null) throw new ArgumentNullException("key"); |
| |
| if (Contains(key)) |
| { |
| throw new ArgumentException("LinkedHashtable already contains key. key=" + key); |
| } |
| |
| LinkedDictionaryEntry de = new LinkedDictionaryEntry(key, value); |
| if (_head == null) |
| { |
| _head = de; |
| _tail = de; |
| } |
| else |
| { |
| _tail._next = de; |
| de._previous = _tail; |
| _tail = de; |
| } |
| _indexedValues[key] = de; |
| } |
| |
| public void Clear() |
| { |
| _indexedValues.Clear(); |
| } |
| |
| IDictionaryEnumerator IDictionary.GetEnumerator() |
| { |
| return new LHTEnumerator(this); |
| } |
| |
| public void Remove(object key) |
| { |
| if (key == null) throw new ArgumentNullException("key"); |
| |
| LinkedDictionaryEntry de = (LinkedDictionaryEntry)_indexedValues[key]; |
| if (de == null) return; // key not found. |
| LinkedDictionaryEntry prev = de._previous; |
| if (prev == null) |
| { |
| _head = de._next; |
| } |
| else |
| { |
| prev._next = de._next; |
| } |
| |
| LinkedDictionaryEntry next = de._next; |
| if (next == null) |
| { |
| _tail = de; |
| } |
| else |
| { |
| next._previous = de._previous; |
| } |
| } |
| |
| private LinkedDictionaryEntry Head |
| { |
| get |
| { |
| return _head; |
| } |
| } |
| |
| // private LinkedDictionaryEntry Tail |
| // { |
| // get |
| // { |
| // return _tail; |
| // } |
| // } |
| |
| private class LHTEnumerator : IDictionaryEnumerator |
| { |
| private LinkedHashtable _container; |
| |
| private LinkedDictionaryEntry _current; |
| |
| /// <summary> |
| /// Set once we have navigated off the end of the collection |
| /// </summary> |
| private bool _needsReset = false; |
| |
| public LHTEnumerator(LinkedHashtable container) |
| { |
| _container = container; |
| } |
| |
| public object Current |
| { |
| get |
| { |
| if (_current == null) |
| { |
| throw new Exception("Iterator before first element"); |
| } |
| else |
| { |
| return _current._entry; |
| } |
| } |
| } |
| |
| public object Key |
| { |
| get { return _current._entry.Key; } |
| } |
| |
| public object Value |
| { |
| get { return _current._entry.Value; } |
| } |
| |
| public DictionaryEntry Entry |
| { |
| get |
| { |
| return _current._entry; |
| } |
| } |
| |
| public bool MoveNext() |
| { |
| if (_needsReset) |
| { |
| return false; |
| } |
| else if (_current == null) |
| { |
| _current = _container.Head; |
| } |
| else |
| { |
| _current = _current._next; |
| } |
| _needsReset = (_current == null); |
| return !_needsReset; |
| } |
| |
| public void Reset() |
| { |
| _current = null; |
| _needsReset = false; |
| } |
| } |
| |
| public void MoveToHead(object key) |
| { |
| LinkedDictionaryEntry de = (LinkedDictionaryEntry)_indexedValues[key]; |
| if (de == null) |
| { |
| throw new ArgumentException("Key " + key + " not found"); |
| } |
| // if the head is the element then there is nothing to do |
| if (_head == de) |
| { |
| return; |
| } |
| de._previous._next = de._next; |
| if (de._next != null) |
| { |
| de._next._previous = de._previous; |
| } |
| else |
| { |
| _tail = de._previous; |
| } |
| de._next = _head; |
| _head = de; |
| de._previous = null; |
| } |
| |
| public void CopyTo(Array array, int index) |
| { |
| _indexedValues.CopyTo(array, index); |
| } |
| |
| public int Count |
| { |
| get { return _indexedValues.Count; } |
| } |
| |
| public object SyncRoot |
| { |
| get { return _indexedValues.SyncRoot; } |
| } |
| |
| public bool IsSynchronized |
| { |
| get { return _indexedValues.IsSynchronized; } |
| } |
| |
| public IEnumerator GetEnumerator() |
| { |
| return new LHTEnumerator(this); |
| } |
| } |
| } |