Struct HashMapBuilder

pub struct HashMapBuilder<K, V, S = RandomState> { /* private fields */ }

A builder for a HashMap.

Examples

use papaya::{HashMap, ResizeMode};
use seize::Collector;
use std::collections::hash_map::RandomState;

let map: HashMap<i32, i32> = HashMap::builder()
    // Set the initial capacity.
    .capacity(2048)
    // Set the hasher.
    .hasher(RandomState::new())
    // Set the resize mode.
    .resize_mode(ResizeMode::Blocking)
    // Set a custom garbage collector.
    .collector(Collector::new().batch_size(128))
    // Construct the hash map.
    .build();

Implementations

impl<K, V> HashMapBuilder<K, V>

pub fn hasher<S>(self, hasher: S) -> HashMapBuilder<K, V, S>

Set the hash builder used to hash keys.

Warning: hash_builder is normally randomly generated, and is designed to allow HashMaps to be resistant to attacks that cause many collisions and very poor performance. Setting it manually using this function can expose a DoS attack vector.

The hash_builder passed should implement the BuildHasher trait for the HashMap to be useful, see its documentation for details.

impl<K, V, S> HashMapBuilder<K, V, S>

pub fn capacity(self, capacity: usize) -> HashMapBuilder<K, V, S>

Set the initial capacity of the map.

The table should be able to hold at least capacity elements before resizing. However, the capacity is an estimate, and the table may prematurely resize due to poor hash distribution. If capacity is 0, the hash map will not allocate.

pub fn resize_mode(self, resize_mode: ResizeMode) -> Self

Set the resizing mode of the map. See ResizeMode for details.

pub fn collector(self, collector: Collector) -> Self

Set the seize::Collector used for garbage collection.

This method may be useful when you want more control over garbage collection.

Note that all Guard references used to access the map must be produced by the provided collector.

pub fn build(self) -> HashMap<K, V, S>

Construct a HashMap from the builder, using the configured options.

Trait Implementations

impl<K, V, S> Debug for HashMapBuilder<K, V, S>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.