Struct Local

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pub struct Local<'env, Class: AsValidJObjectAndEnv> { /* private fields */ }
Expand description

A Local, non-null, reference to a Java object (+ &Env) limited to the current thread/stack.

Including the env allows for the convenient execution of methods without having to individually pass the env as an argument to each and every one. Since this is limited to the current thread/stack, these cannot be sanely stored in any kind of static storage, nor shared between threads - instead use a Global if you need to do either.

Will DeleteLocalRef when dropped, invalidating the jobject but ensuring threads that rarely or never return to Java may run without being guaranteed to eventually exhaust their local reference limit. If this is not desired, convert to a plain Ref with:

let local = Local::leak(local);

Not FFI Safe: #[repr(rust)], and exact layout is likely to change - depending on exact features used - in the future. Specifically, on Android, since we’re guaranteed to only have a single ambient VM, we can likely store the *const JNIEnv in thread local storage instead of lugging it around in every Local. Of course, there’s no guarantee that’s actually an optimization

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impl<'env, Class: AsValidJObjectAndEnv> Local<'env, Class>

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pub unsafe fn from_env_object(env: *const JNIEnv, object: jobject) -> Self

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pub fn leak(local: Self) -> Ref<'env, Class>

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impl<'env, Class: AsValidJObjectAndEnv + Debug> Debug for Local<'env, Class>

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

Formats the value using the given formatter. Read more
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impl<'env, Class: AsValidJObjectAndEnv + Display> Display for Local<'env, Class>

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

Formats the value using the given formatter. Read more
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impl<'env, Class: AsValidJObjectAndEnv> Drop for Local<'env, Class>

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fn drop(&mut self)

Executes the destructor for this type. Read more
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impl<'env, Class: AsValidJObjectAndEnv> From<Local<'env, Class>> for Global<Class>

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fn from(local: Local<'env, Class>) -> Global<Class>

Converts to this type from the input type.
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impl<'env, Class: AsValidJObjectAndEnv> Deref for Local<'env, Class>

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type Target = Class

The resulting type after dereferencing.
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fn deref(&self) -> &Self::Target

Dereferences the value.

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impl<'env, Class> Freeze for Local<'env, Class>

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impl<'env, Class> RefUnwindSafe for Local<'env, Class>
where Class: RefUnwindSafe,

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impl<'env, Class> !Send for Local<'env, Class>

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impl<'env, Class> !Sync for Local<'env, Class>

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impl<'env, Class> Unpin for Local<'env, Class>

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impl<'env, Class> UnwindSafe for Local<'env, Class>
where Class: RefUnwindSafe,

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<P, T> Receiver for P
where P: Deref<Target = T> + ?Sized, T: ?Sized,

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type Target = T

🔬This is a nightly-only experimental API. (arbitrary_self_types)
The target type on which the method may be called.
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impl<T> ToString for T
where T: Display + ?Sized,

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fn to_string(&self) -> String

Converts the given value to a String. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.