Struct hash_rings::rendezvous::Client

pub struct Client<'a, T, U, H = RandomState> { /* fields omitted */ }

A client that uses Ring<T>.

Examples

use hash_rings::rendezvous::Client;

let mut client = Client::new();
client.insert_node(&"node-1", 3);
client.insert_point(&"point-1");
client.insert_point(&"point-2");

assert_eq!(client.len(), 1);
assert_eq!(client.get_node(&"point-1"), &"node-1");

client.remove_point(&"point-2");
assert_eq!(client.get_points(&"node-1"), [&"point-1"]);

Methods

impl<'a, T, U> Client<'a, T, U, RandomState>

pub fn new() -> Self where
    T: Hash + Eq,
    U: Hash + Eq, 

Constructs a new, empty Client<T, U>.

Examples

use hash_rings::rendezvous::Client;

let mut client: Client<&str, &str> = Client::new();

impl<'a, T, U, H> Client<'a, T, U, H>

pub fn with_hasher(hash_builder: H) -> Self where
    T: Hash + Eq,
    U: Hash + Eq,
    H: BuildHasher + Clone, 

Constructs a new, empty Client<T, U> with a specified hash builder.

Examples

use hash_rings::rendezvous::Client;
use std::collections::hash_map::DefaultHasher;
use std::hash::BuildHasherDefault;

type DefaultBuildHasher = BuildHasherDefault<DefaultHasher>;

let mut client: Client<&str, &str, _> = Client::with_hasher(DefaultBuildHasher::default());

pub fn insert_node(&mut self, id: &'a T, replicas: usize) where
    T: Hash + Eq,
    U: Hash + Eq,
    H: BuildHasher, 

Inserts a node into the ring with a number of replicas.

Increasing the number of replicas will increase the number of expected points mapped to the node. For example, a node with three replicas will receive approximately three times more points than a node with one replica.

Examples

use hash_rings::rendezvous::Client;

let mut client: Client<&str, &str> = Client::new();

// "node-2" will receive three times more points than "node-1"
client.insert_node(&"node-1", 1);
client.insert_node(&"node-2", 3);

pub fn remove_node(&mut self, id: &T) where
    T: Hash + Ord,
    U: Hash + Eq,
    H: BuildHasher, 

Removes a node and all its replicas from the ring.

Panics

Panics if the ring is empty after removal of a node or if the node does not exist.

Examples

use hash_rings::rendezvous::Client;

let mut client: Client<&str, &str> = Client::new();

client.insert_node(&"node-1", 1);
client.insert_node(&"node-2", 1);
client.remove_node(&"node-1");

pub fn get_points(&self, id: &T) -> Vec<&U> where
    T: Hash + Eq,
    U: Hash + Eq, 

Returns the points associated with a node and its replicas.

Panics

Panics if the node does not exist.

Examples

use hash_rings::rendezvous::Client;

let mut client: Client<&str, &str> = Client::new();

client.insert_node(&"node-1", 1);
client.insert_point(&"point-1");
assert_eq!(client.get_points(&"node-1"), [&"point-1"]);

pub fn get_node(&self, point: &U) -> &T where
    T: Hash + Ord,
    U: Hash + Eq,
    H: BuildHasher, 

Returns the node associated with a point.

Panics

Panics if the ring is empty.

Examples

use hash_rings::rendezvous::Client;

let mut client: Client<&str, &str> = Client::new();

client.insert_node(&"node-1", 1);
client.insert_point(&"point-1");
assert_eq!(client.get_node(&"point-1"), &"node-1");

pub fn insert_point(&mut self, point: &'a U) -> &T where
    T: Hash + Ord,
    U: Hash + Eq,
    H: BuildHasher, 

Inserts a point into the ring and returns the node associated with the inserted point.

Panics

Panics if the ring is empty.

Examples

use hash_rings::rendezvous::Client;

let mut client = Client::new();
client.insert_node(&"node-1", 1);
client.insert_point(&"point-1");

pub fn remove_point(&mut self, point: &U) where
    T: Hash + Ord,
    U: Hash + Eq,
    H: BuildHasher, 

Removes a point from the ring.

Panics

Panics if the ring is empty.

Examples

use hash_rings::rendezvous::Client;

let mut client = Client::new();
client.insert_node(&"node-1", 1);
client.insert_point(&"point-1");
client.remove_point(&"point-1");

pub fn len(&self) -> usize where
    T: Hash + Eq, 

Returns the number of nodes in the ring.

Examples

use hash_rings::rendezvous::Client;

let mut client: Client<&str, &str> = Client::new();

client.insert_node(&"node-1", 3);
assert_eq!(client.len(), 1);

pub fn is_empty(&self) -> bool where
    T: Hash + Eq, 

Returns true if the ring is empty.

Examples

use hash_rings::rendezvous::Client;

let mut client: Client<&str, &str> = Client::new();

assert!(client.is_empty());
client.insert_node(&"node-1", 3);
assert!(!client.is_empty());

pub fn iter(&'a self) -> impl Iterator<Item = (&'a T, Vec<&'a U>)> where
    T: Hash + Eq,
    U: Hash + Eq, 

Returns an iterator over the ring. The iterator will yield nodes and points in no particular order.

Examples

use hash_rings::rendezvous::Client;

let mut client = Client::new();
client.insert_node(&"node-1", 1);
client.insert_point(&"point-1");

let mut iterator = client.iter();
assert_eq!(iterator.next(), Some((&"node-1", vec![&"point-1"])));
assert_eq!(iterator.next(), None);

Trait Implementations

impl<'a, T, U, H> IntoIterator for &'a Client<'a, T, U, H> where
    T: Hash + Eq,
    U: Hash + Eq, 

type IntoIter = Box<dyn Iterator<Item = (&'a T, Vec<&'a U>)> + 'a>

Which kind of iterator are we turning this into?

type Item = (&'a T, Vec<&'a U>)

The type of the elements being iterated over.

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<'a, T, U, H> Default for Client<'a, T, U, H> where
    T: Hash + Eq,
    U: Hash + Eq,
    H: BuildHasher + Default + Clone, 

fn default() -> Self

Returns the "default value" for a type.