C# 클래스 StopGuessing.Clients.DistributedBinomialLadderFilterClient

The client side of a distributed binomial ladder frequency filter. Binomial ladder filters are used to identify frequently-occuring elements in streams while minimizing the data revealed/stored about infrequently-occuring elements. This client is utilized both by applications using a distributed binomial ladder filter and is also by the servers implementing the server to communicate amongst themselves. For more information about the binomial ladder filter, search its name and "Microsoft Research" to find detailed publications/tech reports.

상속: IBinomialLadderFilter

파일 보기 프로젝트 열기: Microsoft/StopGuessing 1 사용 예제들

공개 프로퍼티들

프로퍼티	타입	설명
MaxLadderHeight	int
MinimumCacheFreshnessRequired	System.TimeSpan
NumberOfShards	int
ShardToHostMapping	IDistributedResponsibilitySet

보호된 프로퍼티들

프로퍼티	타입	설명
CacheOfElementsAtTopOfLadder	DateTime>.FixedSizeLruCache
ShardHashFunction	StopGuessing.EncryptionPrimitives.UniversalHashFunction

공개 메소드들

메소드	설명
AssignRandomBit ( int valueToAssign, int shardNumber = null ) : void	Assign a random element with the binomial ladder filter to either 0 or 1.
DistributedBinomialLadderFilterClient ( int numberOfShards, int defaultHeightOfLadder, IDistributedResponsibilitySet shardToHostMapping, string configurationKey, System.TimeSpan mininmumCacheFreshnessRequired = null ) : System	Create a client for a distributed binomial ladder filter
GetHeightAsync ( string element, int heightOfLadderInRungs = null, System.TimeSpan timeout = null, CancellationToken cancellationToken = newCancellationToken() ) : Task	Get the height of an element on its binomial ladder. The height of an element is the number of the H array elements that are associated with it that have value 1.
GetRandomShardIndex ( ) : int	Get a random shard index from the set of shards that make up the array elements of the binomial ladder filter.
GetShardIndex ( string key ) : int	Get the shard index associated with an element.
StepAsync ( string key, int heightOfLadderInRungs = null, System.TimeSpan timeout = null, CancellationToken cancellationToken = newCancellationToken() ) : Task	The Step operation records the occurrence of an element by increasing the element's height on the binomial ladder. It does this by identify the shard of the filter array associated with the element, fetching the H elements within that shard associated with the element (the element's rungs), and setting one of the elements with value 0 (a rung above the element) to have value 1 (to put it below the element). It then clears two random elements from the entire array (not just the shard). If none of the H rungs associated with an element have value 0, Step will instead set two random elements from within the full array to have value 1.

메소드 상세

AssignRandomBit() 공개 메소드

Assign a random element with the binomial ladder filter to either 0 or 1.

public AssignRandomBit ( int valueToAssign, int shardNumber = null ) : void
valueToAssign	int	The random element will be set to 1 if this parameter is nonzero, and to 0 otherwise.
shardNumber	int	Optioanlly set this optional value to identify a shard number within to select a random element. /// If not set, this method will choose a shard at random.
리턴	void

DistributedBinomialLadderFilterClient() 공개 메소드

Create a client for a distributed binomial ladder filter

public DistributedBinomialLadderFilterClient ( int numberOfShards, int defaultHeightOfLadder, IDistributedResponsibilitySet shardToHostMapping, string configurationKey, System.TimeSpan mininmumCacheFreshnessRequired = null ) : System
numberOfShards	int	The number of shards that the bit array of the binomial ladder filter will be divided into. /// The greater the number of shards, the more evently it can be distributed. However, the number of shards should still /// be a few orders of magnitude smaller than the ladder height.
defaultHeightOfLadder	int	The default ladder height for elements on the ladder.
shardToHostMapping	IDistributedResponsibilitySet	An object that maps each shard number to the host responsible for that shard.
configurationKey	string	A key used to protect the hashing from algorithmic complexity attacks. /// This key should not be unique to the application using the filter and should not be known to any untrusted /// systems that might control which elements get sent to the filter. If an attacker could submit elements to the filter /// and knew this key, the attacker could arrange for all elements to go to the same shard and in so doing overload that shard.
mininmumCacheFreshnessRequired	System.TimeSpan	The maximum time that an element should be kept in the cache of elements at the top of their ladder. /// In other words, how long to bound the possible time that an element may still appear to be at the top of its ladder in the cache /// when it is no longer at the top of the ladder based on the filter array. Defaults to one minute.
리턴	System

GetHeightAsync() 공개 메소드

Get the height of an element on its binomial ladder. The height of an element is the number of the H array elements that are associated with it that have value 1.

public GetHeightAsync ( string element, int heightOfLadderInRungs = null, System.TimeSpan timeout = null, CancellationToken cancellationToken = newCancellationToken() ) : Task
element	string	The element to be measured to determine its height on its binomial ladder.
heightOfLadderInRungs	int	>If set, use a binomial ladder of this height rather than the default height. /// (Must not be greater than the default height that the binmomial ladder was initialized with.
timeout	System.TimeSpan
cancellationToken	System.Threading.CancellationToken
리턴	Task

GetRandomShardIndex() 공개 메소드

Get a random shard index from the set of shards that make up the array elements of the binomial ladder filter.

public GetRandomShardIndex ( ) : int
리턴	int

GetShardIndex() 공개 메소드

Get the shard index associated with an element.

public GetShardIndex ( string key ) : int
key	string	The element to match to a shard index.
리턴	int

StepAsync() 공개 메소드

The Step operation records the occurrence of an element by increasing the element's height on the binomial ladder. It does this by identify the shard of the filter array associated with the element, fetching the H elements within that shard associated with the element (the element's rungs), and setting one of the elements with value 0 (a rung above the element) to have value 1 (to put it below the element). It then clears two random elements from the entire array (not just the shard). If none of the H rungs associated with an element have value 0, Step will instead set two random elements from within the full array to have value 1.

public StepAsync ( string key, int heightOfLadderInRungs = null, System.TimeSpan timeout = null, CancellationToken cancellationToken = newCancellationToken() ) : Task
key	string	The element to take a step for.
heightOfLadderInRungs	int	If set, use a binomial ladder of this height rather than the default height. /// (Must not be greater than the default height that the binmomial ladder was initialized with.)
timeout	System.TimeSpan
cancellationToken	System.Threading.CancellationToken
리턴	Task

프로퍼티 상세

CacheOfElementsAtTopOfLadder 보호되어 있는 프로퍼티

A LRU cache of elements that are at the top of their ladder, used less to improve performance and more to prevent a single node from being overloaded if all requests target a single element.

protected FixedSizeLruCache CacheOfElementsAtTopOfLadder
리턴	DateTime>.FixedSizeLruCache

MaxLadderHeight 공개적으로 프로퍼티

The maximum (and default) height of elements' ladders.

public int MaxLadderHeight
리턴	int

MinimumCacheFreshnessRequired 공개적으로 프로퍼티

The maximum amount of time an element should allowed to be treated as at the top of its ladder due to caching when it may actually have fallen down the ladder since the value was cached.

public TimeSpan,System MinimumCacheFreshnessRequired
리턴	System.TimeSpan

NumberOfShards 공개적으로 프로퍼티

The number of shards that the filter array is evenly divided into.

public int NumberOfShards
리턴	int

ShardHashFunction 보호되어 있는 프로퍼티

The hash function used to map elements to shards.

protected UniversalHashFunction,StopGuessing.EncryptionPrimitives ShardHashFunction
리턴	StopGuessing.EncryptionPrimitives.UniversalHashFunction

ShardToHostMapping 공개적으로 프로퍼티

Records for each shard that is (or at one time has been) stored on this server.

public IDistributedResponsibilitySet ShardToHostMapping
리턴	IDistributedResponsibilitySet