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use JNIEnv;
use errors::*;
use objects::JObject;
use objects::JClass;
use objects::JMethodID;
use signature::JavaType;
use signature::Primitive;
/// Wrapper for JObjects that implement `java/util/Map`. Provides methods to get
/// and set entries and a way to iterate over key/value pairs.
///
/// Looks up the class and method ids on creation rather than for every method
/// call.
pub struct JMap<'a> {
internal: JObject<'a>,
class: JClass<'a>,
get: JMethodID<'a>,
put: JMethodID<'a>,
remove: JMethodID<'a>,
env: &'a JNIEnv<'a>,
}
impl<'a> ::std::ops::Deref for JMap<'a> {
type Target = JObject<'a>;
fn deref(&self) -> &Self::Target {
&self.internal
}
}
impl<'a> From<JMap<'a>> for JObject<'a> {
fn from(other: JMap) -> JObject {
other.internal
}
}
impl<'a> JMap<'a> {
/// Create a map from the environment and an object. This looks up the
/// necessary class and method ids to call all of the methods on it so that
/// exra work doesn't need to be done on every method call.
pub fn from_env(env: &'a JNIEnv<'a>, obj: JObject<'a>) -> Result<JMap<'a>> {
let class = env.find_class("java/util/Map")?;
let get = env.get_method_id(class,
"get",
"(Ljava/lang/Object;)Ljava/lang/Object;")?;
let put = env.get_method_id(class,
"put",
"(Ljava/lang/Object;Ljava/lang/Object;\
)Ljava/lang/Object;")?;
let remove = env.get_method_id(class,
"remove",
"(Ljava/lang/Object;)Ljava/lang/Object;")?;
Ok(JMap {
internal: obj,
class: class,
get: get,
put: put,
remove: remove,
env: env,
})
}
/// Look up the value for a key. Returns `Some` if it's found and `None` if
/// a null pointer would be returned.
pub fn get(&self, key: JObject<'a>) -> Result<Option<JObject>> {
let result = unsafe {
self.env.call_method_unsafe(self.internal,
self.get,
JavaType::Object("java/lang/Object"
.into()),
&[key.into()])
};
match result {
Ok(val) => Ok(Some(val.l()?)),
Err(e) => {
match e.kind() {
&ErrorKind::NullPtr(_) => Ok(None),
_ => Err(e),
}
}
}
}
/// Look up the value for a key. Returns `Some` with the old value if the
/// key already existed and `None` if it's a new key.
pub fn put(&self,
key: JObject<'a>,
value: JObject<'a>)
-> Result<Option<JObject>> {
let result = unsafe {
self.env.call_method_unsafe(self.internal,
self.put,
JavaType::Object("java/lang/Object"
.into()),
&[key.into(), value.into()])
};
match result {
Ok(val) => Ok(Some(val.l()?)),
Err(e) => {
match e.kind() {
&ErrorKind::NullPtr(_) => Ok(None),
_ => Err(e),
}
}
}
}
/// Remove a value from the map. Returns `Some` with the removed value and
/// `None` if there was no value for the key.
pub fn remove(&self, key: JObject<'a>) -> Result<Option<JObject<'a>>> {
let result = unsafe {
self.env.call_method_unsafe(self.internal,
self.remove,
JavaType::Object("java/lang/Object"
.into()),
&[key.into()])
};
match result {
Ok(val) => Ok(Some(val.l()?)),
Err(e) => {
match e.kind() {
&ErrorKind::NullPtr(_) => Ok(None),
_ => Err(e),
}
}
}
}
/// Get key/value iterator for the map. This is done by getting the
/// `EntrySet` from java and iterating over it.
pub fn iter(&'a self) -> Result<JMapIter<'a>> {
let set = unsafe {
let set = self.env
.call_method_unsafe(self.internal,
(self.class,
"entrySet",
"()Ljava/util/Set;"),
JavaType::Object("java/util/Set".into()),
&[])?;
set.l()?
};
let iter = unsafe {
let iter = self.env
.call_method_unsafe(set,
("java/util/Set",
"iterator",
"()Ljava/util/Iterator;"),
JavaType::Object("java/util/Iterator"
.into()),
&[])?;
iter.l()?
};
let iter_class = self.env
.find_class("java/util/Iterator")?;
let has_next = self.env
.get_method_id(iter_class, "hasNext", "()Z")?;
let next = self.env
.get_method_id(iter_class, "next", "()Ljava/lang/Object;")?;
let entry_class = self.env
.find_class("java/util/Map$Entry")?;
let get_key = self.env
.get_method_id(entry_class, "getKey", "()Ljava/lang/Object;")?;
let get_value = self.env
.get_method_id(entry_class, "getValue", "()Ljava/lang/Object;")?;
Ok(JMapIter {
map: &self,
has_next: has_next,
next: next,
get_key: get_key,
get_value: get_value,
iter: iter,
})
}
}
/// An iterator over the keys and values in a map.
///
/// TODO: make the iterator implementation for java iterators its own thing
/// and generic enough to use elsewhere.
pub struct JMapIter<'a> {
map: &'a JMap<'a>,
has_next: JMethodID<'a>,
next: JMethodID<'a>,
get_key: JMethodID<'a>,
get_value: JMethodID<'a>,
iter: JObject<'a>,
}
impl<'a> JMapIter<'a> {
fn get_next(&self) -> Result<Option<(JObject<'a>, JObject<'a>)>> {
let has_next = unsafe {
let val = self.map
.env
.call_method_unsafe(self.iter,
self.has_next,
JavaType::Primitive(Primitive::Boolean),
&[])?;
val.z()?
};
if !has_next {
return Ok(None);
}
let next = unsafe {
let next = self.map
.env
.call_method_unsafe(self.iter,
self.next,
JavaType::Object("java/util/Map$Entry"
.into()),
&[])?;
next.l()?
};
let key = unsafe {
let key = self.map
.env
.call_method_unsafe(next,
self.get_key,
JavaType::Object("java/lang/Object"
.into()),
&[])?;
key.l()?
};
let value = unsafe {
let value = self.map
.env
.call_method_unsafe(next,
self.get_value,
JavaType::Object("java/lang/Object"
.into()),
&[])?;
value.l()?
};
Ok(Some((key, value)))
}
}
impl<'a> Iterator for JMapIter<'a> {
type Item = (JObject<'a>, JObject<'a>);
fn next(&mut self) -> Option<Self::Item> {
match self.get_next() {
Ok(Some(n)) => Some(n),
_ => None,
}
}
}