Struct jni::objects::JMapIter

pub struct JMapIter<'map, 'local, 'other_local_1: 'obj_ref, 'obj_ref, 'iter_local> { /* private fields */ }

An iterator over the keys and values in a map. See JMap::iter for more information.

TODO: make the iterator implementation for java iterators its own thing and generic enough to use elsewhere.

Implementations

impl<'map, 'local, 'other_local_1: 'obj_ref, 'obj_ref, 'iter_local> JMapIter<'map, 'local, 'other_local_1, 'obj_ref, 'iter_local>

pub fn next<'other_local_2>( &mut self, env: &mut JNIEnv<'other_local_2> ) -> Result<Option<(JObject<'other_local_2>, JObject<'other_local_2>)>>

Advances the iterator and returns the next key-value pair in the java.util.Map, or None if there are no more objects.

See JMap::iter for more information.

This method creates two new local references. To prevent excessive memory usage or overflow error, the local references should be deleted using JNIEnv::delete_local_ref or JNIEnv::auto_local before the next loop iteration. Alternatively, if the map is known to have a small, predictable size, the loop could be wrapped in JNIEnv::with_local_frame to delete all of the local references at once.

This method returns:

• Ok(Some(_)): if there was another key-value pair in the map.
• Ok(None): if there are no more key-value pairs in the map.
• Err(_): if there was an error calling the Java method to get the next key-value pair.

This is like std::iter::Iterator::next, but requires a parameter of type &mut JNIEnv in order to call into Java.