Struct ThreadPoolBuilder 

pub struct ThreadPoolBuilder { /* private fields */ }

Builder for ThreadPool.

The default builder uses the available CPU parallelism as both core and maximum pool size, with an unbounded FIFO queue.

Implementations

impl ThreadPoolBuilder

pub fn pool_size(self, pool_size: usize) -> ThreadPoolBuilder

Sets both the core and maximum pool size to the same value.

Parameters

• pool_size - Pool size applied as both core and maximum limits.

Returns

This builder for fluent configuration.

pub fn core_pool_size(self, core_pool_size: usize) -> ThreadPoolBuilder

Sets the core pool size.

A submitted task creates a new worker while the live worker count is below this value. Once the core size is reached, tasks are queued before the pool considers growing toward the maximum size.

Parameters

• core_pool_size - Core pool size.

Returns

This builder for fluent configuration.

pub fn maximum_pool_size(self, maximum_pool_size: usize) -> ThreadPoolBuilder

Sets the maximum pool size.

The pool grows above the core size only when the queue cannot accept a submitted task.

Parameters

• maximum_pool_size - Maximum pool size.

Returns

This builder for fluent configuration.

pub fn queue_capacity(self, capacity: usize) -> ThreadPoolBuilder

Sets a bounded queue capacity.

The capacity counts only tasks waiting in the queue. Tasks already held by worker threads are not included.

Parameters

• capacity - Maximum number of queued tasks.

Returns

This builder for fluent configuration.

pub fn unbounded_queue(self) -> ThreadPoolBuilder

Uses an unbounded queue.

Returns

This builder for fluent configuration.

pub fn thread_name_prefix(self, prefix: &str) -> ThreadPoolBuilder

Sets the worker thread name prefix.

Worker names are created by appending the worker index to this prefix.

Parameters

• prefix - Prefix for worker thread names.

Returns

This builder for fluent configuration.

pub fn stack_size(self, stack_size: usize) -> ThreadPoolBuilder

Sets the worker thread stack size.

Parameters

• stack_size - Stack size in bytes for each worker thread.

Returns

This builder for fluent configuration.

pub fn keep_alive(self, keep_alive: Duration) -> ThreadPoolBuilder

Sets the idle timeout for workers above the core pool size.

Parameters

• keep_alive - Duration an excess worker may stay idle.

Returns

This builder for fluent configuration.

pub fn allow_core_thread_timeout(self, allow: bool) -> ThreadPoolBuilder

Allows core workers to retire after the keep-alive timeout.

Parameters

• allow - Whether idle core workers may time out.

Returns

This builder for fluent configuration.

pub fn prestart_core_threads(self) -> ThreadPoolBuilder

Starts all core workers during Self::build.

Without this option, workers are created lazily as tasks are submitted, matching the default JDK ThreadPoolExecutor behavior.

Returns

This builder for fluent configuration.

pub fn before_worker_start<F>(self, hook: F) -> ThreadPoolBuilder

where F: Fn(usize) + Send + Sync + 'static,

Installs a callback invoked when a worker thread starts.

Parameters

• hook - Callback receiving the stable worker index.

Returns

This builder for fluent configuration.

pub fn after_worker_stop<F>(self, hook: F) -> ThreadPoolBuilder

where F: Fn(usize) + Send + Sync + 'static,

Installs a callback invoked before a worker thread exits.

Parameters

• hook - Callback receiving the stable worker index.

Returns

This builder for fluent configuration.

pub fn before_task<F>(self, hook: F) -> ThreadPoolBuilder

where F: Fn(usize) + Send + Sync + 'static,

Installs a callback invoked before each job is run.

Parameters

• hook - Callback receiving the stable worker index.

Returns

This builder for fluent configuration.

pub fn after_task<F>(self, hook: F) -> ThreadPoolBuilder

where F: Fn(usize) + Send + Sync + 'static,

Installs a callback invoked after each job is run.

Parameters

• hook - Callback receiving the stable worker index.

Returns

This builder for fluent configuration.

pub fn build(self) -> Result<ThreadPool, ExecutorServiceBuilderError>

Builds the configured thread pool.

Returns

Ok(ThreadPool) if the configuration is valid and all requested prestarted workers are spawned successfully.

Errors

Returns ExecutorServiceBuilderError if the configuration is invalid or a prestarted worker thread cannot be spawned.

Trait Implementations

impl Clone for ThreadPoolBuilder

fn clone(&self) -> ThreadPoolBuilder

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ThreadPoolBuilder

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

Formats the value using the given formatter.

impl Default for ThreadPoolBuilder

fn default() -> ThreadPoolBuilder

Creates a builder with CPU parallelism defaults.

Returns

A builder configured with CPU parallelism for both core and maximum sizes, an unbounded queue, and the default keep-alive timeout.