Class LurchTable<TKey, TValue>

LurchTable stands for "Least Used Recently Concurrent Hash Table" and has definate similarities to both the .NET 4 ConcurrentDictionary as well as Java's LinkedHashMap. This gives you a thread-safe dictionary/hashtable that stores element ordering by insertion, updates, or access. In addition it can be configured to use a 'hard-limit' count of items that will automatically 'pop' the oldest item in the collection.

Inheritance

System.Object

LurchTable<TKey, TValue>

Implements

IDisposable

Namespace: Lucene.Net.Support

Assembly: Lucene.Net.dll

Syntax

public class LurchTable<TKey, TValue> : IDictionary<TKey, TValue>, IDisposable

Type Parameters

Name	Description
TKey	The type of keys in the dictionary.
TValue	The type of values in the dictionary.

Constructors

LurchTable(LurchTableOrder, Int32)

Creates a LurchTable that orders items by ordering and removes items once the specified limit is reached.

Declaration

public LurchTable(LurchTableOrder ordering, int limit)

Parameters

Type	Name	Description
LurchTableOrder	ordering	The type of linking for the items
System.Int32	limit	The maximum allowable number of items, or int.MaxValue for unlimited

LurchTable(LurchTableOrder, Int32, IEqualityComparer<TKey>)

Creates a LurchTable that orders items by ordering and removes items once the specified limit is reached.

Declaration

public LurchTable(LurchTableOrder ordering, int limit, IEqualityComparer<TKey> comparer)

Parameters

Type	Name	Description
LurchTableOrder	ordering	The type of linking for the items
System.Int32	limit	The maximum allowable number of items, or int.MaxValue for unlimited
IEqualityComparer<TKey>	comparer	The element hash generator for keys, or null to use

LurchTable(LurchTableOrder, Int32, Int32, Int32, Int32, IEqualityComparer<TKey>)

Creates a LurchTable that orders items by ordering and removes items once the specified limit is reached.

Declaration

public LurchTable(LurchTableOrder ordering, int limit, int hashSize, int allocSize, int lockSize, IEqualityComparer<TKey> comparer)

Parameters

Type	Name	Description
LurchTableOrder	ordering	The type of linking for the items
System.Int32	limit	The maximum allowable number of items, or int.MaxValue for unlimited
System.Int32	hashSize	The number of hash buckets to use for the collection, usually 1/2 estimated capacity
System.Int32	allocSize	The number of entries to allocate at a time, usually 1/16 estimated capacity
System.Int32	lockSize	The number of concurrency locks to preallocate, usually 1/256 estimated capacity
IEqualityComparer<TKey>	comparer	The element hash generator for keys, or null to use

LurchTable(Int32)

Creates a LurchTable that can store up to capacity items efficiently.

Declaration

public LurchTable(int capacity)

Parameters

Type	Name	Description
System.Int32	capacity	The initial allowable number of items before allocation of more memory

LurchTable(Int32, LurchTableOrder)

Creates a LurchTable that can store up to capacity items efficiently.

Declaration

public LurchTable(int capacity, LurchTableOrder ordering)

Parameters

Type	Name	Description
System.Int32	capacity	The initial allowable number of items before allocation of more memory
LurchTableOrder	ordering	The type of linking for the items

LurchTable(Int32, LurchTableOrder, IEqualityComparer<TKey>)

Creates a LurchTable that can store up to capacity items efficiently.

Declaration

public LurchTable(int capacity, LurchTableOrder ordering, IEqualityComparer<TKey> comparer)

Parameters

Type	Name	Description
System.Int32	capacity	The initial allowable number of items before allocation of more memory
LurchTableOrder	ordering	The type of linking for the items
IEqualityComparer<TKey>	comparer	The element hash generator for keys, or null to use

Properties

Comparer

Retrives the key comparer being used by this instance.

Declaration

public IEqualityComparer<TKey> Comparer { get; }

Property Value

Type	Description
IEqualityComparer<TKey>

Count

Gets the number of elements contained in the System.Collections.Generic.ICollection<>.

Declaration

public int Count { get; }

Property Value

Type	Description
System.Int32

Item[TKey]

Gets or sets the element with the specified key.

Declaration

public TValue this[TKey key] { get; set; }

Parameters

Type	Name	Description
TKey	key

Property Value

Type	Description
TValue

Keys

Gets an System.Collections.Generic.ICollection<> containing the keys of the System.Collections.Generic.IDictionary<, >.

Declaration

public LurchTable<TKey, TValue>.KeyCollection Keys { get; }

Property Value

Type	Description
LurchTable.KeyCollection<>

Limit

Gets or Sets the record limit allowed in this instance.

Declaration

public int Limit { get; set; }

Property Value

Type	Description
System.Int32

Ordering

Retrieves the LurchTableOrder Ordering enumeration this instance was created with.

Declaration

public LurchTableOrder Ordering { get; }

Property Value

Type	Description
LurchTableOrder

Values

Gets an System.Collections.Generic.ICollection<> containing the values in the System.Collections.Generic.IDictionary<, >.

Declaration

public LurchTable<TKey, TValue>.ValueCollection Values { get; }

Property Value

Type	Description
LurchTable.ValueCollection<>

Methods

Add(TKey, TValue)

Adds an element with the provided key and value to the System.Collections.Generic.IDictionary<, >.

Declaration

public void Add(TKey key, TValue value)

Parameters

Type	Name	Description
TKey	key
TValue	value

AddOrUpdate(TKey, TValue, KeyValueUpdate<TKey, TValue>)

Adds a key/value pair to the System.Collections.Generic.IDictionary<, > if the key does not already exist, or updates a key/value pair if the key already exists.

Declaration

public TValue AddOrUpdate(TKey key, TValue addValue, KeyValueUpdate<TKey, TValue> fnUpdate)

Parameters

Type	Name	Description
TKey	key
TValue	addValue
KeyValueUpdate<TKey, TValue>	fnUpdate

Returns

Type	Description
TValue

AddOrUpdate(TKey, Func<TKey, TValue>, KeyValueUpdate<TKey, TValue>)

Adds a key/value pair to the System.Collections.Generic.IDictionary<, > if the key does not already exist, or updates a key/value pair if the key already exists.

Declaration

public TValue AddOrUpdate(TKey key, Func<TKey, TValue> fnCreate, KeyValueUpdate<TKey, TValue> fnUpdate)

Parameters

Type	Name	Description
TKey	key
Func<TKey, TValue>	fnCreate
KeyValueUpdate<TKey, TValue>	fnUpdate

Returns

Type	Description
TValue

Remarks

Adds or modifies an element with the provided key and value. If the key does not exist in the collection, the factory method fnCreate will be called to produce the new value, if the key exists, the converter method fnUpdate will be called to create an updated value.

AddOrUpdate<T>(TKey, ref T)

Add, update, or fetche a key/value pair from the dictionary via an implementation of the CSharpTest.Net.Collections.ICreateOrUpdateValue`2 interface.

Declaration

public bool AddOrUpdate<T>(TKey key, ref T createOrUpdateValue)
    where T : ICreateOrUpdateValue<TKey, TValue>

Parameters

Type	Name	Description
TKey	key
T	createOrUpdateValue

Returns

Type	Description
System.Boolean

Type Parameters

Name	Description
T

Clear()

Removes all items from the System.Collections.Generic.ICollection<>.

Declaration

public void Clear()

ContainsKey(TKey)

Determines whether the System.Collections.Generic.IDictionary<, > contains an element with the specified key.

Declaration

public bool ContainsKey(TKey key)

Parameters

Type	Name	Description
TKey	key

Returns

Type	Description
System.Boolean

Dequeue()

Removes the oldest entry in the collection based on the ordering supplied to the constructor. If an item is not available a busy-wait loop is used to wait for for an item.

Declaration

public KeyValuePair<TKey, TValue> Dequeue()

Returns

Type	Description
KeyValuePair<TKey, TValue>	The Key/Value pair removed.

Dispose()

Clears references to all objects and invalidates the collection

Declaration

public void Dispose()

GetEnumerator()

Returns an enumerator that iterates through the collection.

Declaration

public LurchTable<TKey, TValue>.Enumerator GetEnumerator()

Returns

Type	Description
LurchTable.Enumerator<>

GetOrAdd(TKey, TValue)

Adds a key/value pair to the System.Collections.Generic.IDictionary<, > if the key does not already exist.

Declaration

public TValue GetOrAdd(TKey key, TValue value)

Parameters

Type	Name	Description
TKey	key	The key of the element to add.
TValue	value	The value to be added, if the key does not already exist.

Returns

Type	Description
TValue

GetOrAdd(TKey, Func<TKey, TValue>)

Adds a key/value pair to the System.Collections.Generic.IDictionary<, > if the key does not already exist.

Declaration

public TValue GetOrAdd(TKey key, Func<TKey, TValue> fnCreate)

Parameters

Type	Name	Description
TKey	key	The key of the element to add.
Func<TKey, TValue>	fnCreate	Constructs a new value for the key.

Returns

Type	Description
TValue

Initialize()

WARNING: not thread-safe, reinitializes all internal structures. Use Clear() for a thread-safe delete all. If you have externally provided exclusive access this method may be used to more efficiently clear the collection.

Declaration

public void Initialize()

Peek(out KeyValuePair<TKey, TValue>)

Retrieves the oldest entry in the collection based on the ordering supplied to the constructor.

Declaration

public bool Peek(out KeyValuePair<TKey, TValue> value)

Parameters

Type	Name	Description
KeyValuePair<TKey, TValue>	value

Returns

Type	Description
System.Boolean	True if the out parameter value was set.

Remove(TKey)

Removes the element with the specified key from the System.Collections.Generic.IDictionary<, >.

Declaration

public bool Remove(TKey key)

Parameters

Type	Name	Description
TKey	key	The key of the element to remove.

Returns

Type	Description
System.Boolean	true if the element is successfully removed; otherwise, false. This method also returns false if key was not found in the original System.Collections.Generic.IDictionary<, >.

TryAdd(TKey, TValue)

Adds an element with the provided key and value to the System.Collections.Generic.IDictionary<, >.

Declaration

public bool TryAdd(TKey key, TValue value)

Parameters

Type	Name	Description
TKey	key	The object to use as the key of the element to add.
TValue	value	The object to use as the value of the element to add.

Returns

Type	Description
System.Boolean

TryAdd(TKey, Func<TKey, TValue>)

Adds an element with the provided key and value to the System.Collections.Generic.IDictionary<, > by calling the provided factory method to construct the value if the key is not already present in the collection.

Declaration

public bool TryAdd(TKey key, Func<TKey, TValue> fnCreate)

Parameters

Type	Name	Description
TKey	key
Func<TKey, TValue>	fnCreate

Returns

Type	Description
System.Boolean

TryDequeue(out KeyValuePair<TKey, TValue>)

Removes the oldest entry in the collection based on the ordering supplied to the constructor.

Declaration

public bool TryDequeue(out KeyValuePair<TKey, TValue> value)

Parameters

Type	Name	Description
KeyValuePair<TKey, TValue>	value

Returns

Type	Description
System.Boolean	False if no item was available

TryDequeue(Predicate<KeyValuePair<TKey, TValue>>, out KeyValuePair<TKey, TValue>)

Removes the oldest entry in the collection based on the ordering supplied to the constructor.

Declaration

public bool TryDequeue(Predicate<KeyValuePair<TKey, TValue>> predicate, out KeyValuePair<TKey, TValue> value)

Parameters

Type	Name	Description
Predicate<KeyValuePair<TKey, TValue>>	predicate
KeyValuePair<TKey, TValue>	value

Returns

Type	Description
System.Boolean	False if no item was available

TryGetValue(TKey, out TValue)

Gets the value associated with the specified key.

Declaration

public bool TryGetValue(TKey key, out TValue value)

Parameters

Type	Name	Description
TKey	key
TValue	value

Returns

Type	Description
System.Boolean	true if the object that implements System.Collections.Generic.IDictionary<, > contains an element with the specified key; otherwise, false.

TryRemove(TKey, out TValue)

Removes the element with the specified key from the System.Collections.Generic.IDictionary<, >.

Declaration

public bool TryRemove(TKey key, out TValue value)

Parameters

Type	Name	Description
TKey	key	The key of the element to remove.
TValue	value	The value that was removed.

Returns

Type	Description
System.Boolean	true if the element is successfully removed; otherwise, false. This method also returns false if key was not found in the original System.Collections.Generic.IDictionary<, >.

TryRemove(TKey, KeyValuePredicate<TKey, TValue>)

Removes the element with the specified key from the System.Collections.Generic.IDictionary<, > if the fnCondition predicate is null or returns true.

Declaration

public bool TryRemove(TKey key, KeyValuePredicate<TKey, TValue> fnCondition)

Parameters

Type	Name	Description
TKey	key
KeyValuePredicate<TKey, TValue>	fnCondition

Returns

Type	Description
System.Boolean

TryRemove<T>(TKey, ref T)

Conditionally removes a key/value pair from the dictionary via an implementation of the CSharpTest.Net.Collections.IRemoveValue`2 interface.

Declaration

public bool TryRemove<T>(TKey key, ref T removeValue)
    where T : IRemoveValue<TKey, TValue>

Parameters

Type	Name	Description
TKey	key
T	removeValue

Returns

Type	Description
System.Boolean

Type Parameters

Name	Description
T

TryUpdate(TKey, TValue)

Updates an element with the provided key to the value if it exists.

Declaration

public bool TryUpdate(TKey key, TValue value)

Parameters

Type	Name	Description
TKey	key	The object to use as the key of the element to update.
TValue	value	The new value for the key if found.

Returns

Type	Description
System.Boolean	Returns true if the key provided was found and updated to the value.

TryUpdate(TKey, TValue, TValue)

Updates an element with the provided key to the value if it exists.

Declaration

public bool TryUpdate(TKey key, TValue value, TValue comparisonValue)

Parameters

Type	Name	Description
TKey	key	The object to use as the key of the element to update.
TValue	value	The new value for the key if found.
TValue	comparisonValue	The value that is compared to the value of the element with key.

Returns

Type	Description
System.Boolean	Returns true if the key provided was found and updated to the value.

TryUpdate(TKey, KeyValueUpdate<TKey, TValue>)

Modify the value associated with the result of the provided update method as an atomic operation, Allows for reading/writing a single record within the syncronization lock.

Declaration

public bool TryUpdate(TKey key, KeyValueUpdate<TKey, TValue> fnUpdate)

Parameters

Type	Name	Description
TKey	key
KeyValueUpdate<TKey, TValue>	fnUpdate

Returns

Type	Description
System.Boolean

Events

ItemAdded

Event raised after an item is added to the collection

Declaration

public event Action<KeyValuePair<TKey, TValue>> ItemAdded

Event Type

Type	Description
Action<KeyValuePair<TKey, TValue>>

ItemRemoved

Event raised after an item is removed from the collection

Declaration

public event Action<KeyValuePair<TKey, TValue>> ItemRemoved

Event Type

Type	Description
Action<KeyValuePair<TKey, TValue>>

ItemUpdated

Event raised after an item is updated in the collection

Declaration

public event LurchTable<TKey, TValue>.ItemUpdatedMethod ItemUpdated

Event Type

Type	Description
LurchTable.ItemUpdatedMethod<>

Implements

IDisposable