Struct remoc_obs::hashmap::ObservableHashMap

source · [−]
pub struct ObservableHashMap<K, V, Codec = Default> { /* private fields */ }
Expand description

A hash map that emits an event for each change.

Use subscribe to obtain an event stream that can be used for building a mirror of this hash map.

Implementations

Creates an empty observable hash map.

Sets the error handler function that is called when sending a change event fails.

Subscribes to change events from this observable hash map.

The current contents of the hash map is included as well.

Inserts a value under a key.

A HashMapEvent::Set change event is sent.

Returns the value previously stored under the key, if any.

Removes the value under the specified key.

A HashMapEvent::Remove change event is sent.

The value is returned.

Removes all items.

A HashMapEvent::Clear change event is sent.

Retains only the elements specified by the predicate.

A HashMapEvent::Remove change event is sent for every element that is removed.

Gets a mutable reference to the value under the specified key.

A HashMapEvent::Set change event is sent if the reference is accessed mutably.

Mutably iterates over the key-value pairs.

A HashMapEvent::Set change event is sent for each value that is accessed mutably.

Shrinks the capacity of the hash map as much as possible.

Methods from Deref<Target = HashMap<K, V>>

Returns the number of elements the map can hold without reallocating.

This number is a lower bound; the HashMap<K, V> might be able to hold more, but is guaranteed to be able to hold at least this many.

Examples
use std::collections::HashMap;
let map: HashMap<i32, i32> = HashMap::with_capacity(100);
assert!(map.capacity() >= 100);

An iterator visiting all keys in arbitrary order. The iterator element type is &'a K.

Examples
use std::collections::HashMap;

let map = HashMap::from([
    ("a", 1),
    ("b", 2),
    ("c", 3),
]);

for key in map.keys() {
    println!("{}", key);
}

An iterator visiting all values in arbitrary order. The iterator element type is &'a V.

Examples
use std::collections::HashMap;

let map = HashMap::from([
    ("a", 1),
    ("b", 2),
    ("c", 3),
]);

for val in map.values() {
    println!("{}", val);
}

An iterator visiting all key-value pairs in arbitrary order. The iterator element type is (&'a K, &'a V).

Examples
use std::collections::HashMap;

let map = HashMap::from([
    ("a", 1),
    ("b", 2),
    ("c", 3),
]);

for (key, val) in map.iter() {
    println!("key: {} val: {}", key, val);
}

Returns the number of elements in the map.

Examples
use std::collections::HashMap;

let mut a = HashMap::new();
assert_eq!(a.len(), 0);
a.insert(1, "a");
assert_eq!(a.len(), 1);

Returns true if the map contains no elements.

Examples
use std::collections::HashMap;

let mut a = HashMap::new();
assert!(a.is_empty());
a.insert(1, "a");
assert!(!a.is_empty());

Returns a reference to the map’s BuildHasher.

Examples
use std::collections::HashMap;
use std::collections::hash_map::RandomState;

let hasher = RandomState::new();
let map: HashMap<i32, i32> = HashMap::with_hasher(hasher);
let hasher: &RandomState = map.hasher();

Returns a reference to the value corresponding to the key.

The key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

Examples
use std::collections::HashMap;

let mut map = HashMap::new();
map.insert(1, "a");
assert_eq!(map.get(&1), Some(&"a"));
assert_eq!(map.get(&2), None);

Returns the key-value pair corresponding to the supplied key.

The supplied key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

Examples
use std::collections::HashMap;

let mut map = HashMap::new();
map.insert(1, "a");
assert_eq!(map.get_key_value(&1), Some((&1, &"a")));
assert_eq!(map.get_key_value(&2), None);

Returns true if the map contains a value for the specified key.

The key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

Examples
use std::collections::HashMap;

let mut map = HashMap::new();
map.insert(1, "a");
assert_eq!(map.contains_key(&1), true);
assert_eq!(map.contains_key(&2), false);
source

pub fn raw_entry(&self) -> RawEntryBuilder<'_, K, V, S>

🔬 This is a nightly-only experimental API. (hash_raw_entry)

Creates a raw immutable entry builder for the HashMap.

Raw entries provide the lowest level of control for searching and manipulating a map. They must be manually initialized with a hash and then manually searched.

This is useful for

  • Hash memoization
  • Using a search key that doesn’t work with the Borrow trait
  • Using custom comparison logic without newtype wrappers

Unless you are in such a situation, higher-level and more foolproof APIs like get should be preferred.

Immutable raw entries have very limited use; you might instead want raw_entry_mut.

Trait Implementations

Formats the value using the given formatter. Read more

Returns the “default value” for a type. Read more

The resulting type after dereferencing.

Dereferences the value.

Performs the conversion.

Performs the conversion.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Performs the conversion.

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more

Instruments this type with the current Span, returning an Instrumented wrapper. Read more

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more