Trait tokens::ChangeToken

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pub trait ChangeToken: Send + Sync {
    // Required methods
    fn changed(&self) -> bool;
    fn register(
        &self,
        callback: Callback,
        state: Option<Arc<dyn Any>>
    ) -> Registration;

    // Provided method
    fn must_poll(&self) -> bool { ... }
}

Expand description

Propagates notifications that a change has occurred.

Required Methods§

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fn changed(&self) -> bool

Gets a value that indicates if a change has occurred.

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fn register( &self, callback: Callback, state: Option<Arc<dyn Any>> ) -> Registration

Registers for a callback that will be invoked when the token has changed.

Arguments

callback - The callback to invoke
state - The optional state provided to the callback, if any

Returns

An opaque change token registration. When it is dropped, the callback function is unregistered.

Provided Methods§

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fn must_poll(&self) -> bool

Indicates if this token will proactively raise callbacks.

Remarks

If false, the token consumer should expect for that any callback specified in register will be invoked when a change occurs. If false, the token consumer must poll changed to detect changes.