Make GenServers to implement Default

concurrency/src/tasks/gen_server.rs

@@ -120,15 +120,17 @@ pub enum CastResponse<G: GenServer> {
 
 pub trait GenServer
 where
-    Self: Send + Sized,
+    Self: Default + Send + Sized,
 {
     type CallMsg: Clone + Send + Sized + Sync;
     type CastMsg: Clone + Send + Sized + Sync;
     type OutMsg: Send + Sized;
     type State: Clone + Send;
     type Error: Debug + Send;
 
-    fn new() -> Self;
+    fn new() -> Self {
+        Self::default()
+    }
 
     fn start(initial_state: Self::State) -> GenServerHandle<Self> {
         GenServerHandle::new(initial_state)
@@ -307,6 +309,8 @@ mod tests {
     use super::*;
     use crate::tasks::send_after;
     use std::{thread, time::Duration};
+
+    #[derive(Default)]
     struct BadlyBehavedTask;
 
     #[derive(Clone)]
@@ -326,10 +330,6 @@ mod tests {
         type State = ();
         type Error = ();
 
-        fn new() -> Self {
-            Self {}
-        }
-
         async fn handle_call(
             &mut self,
             _: Self::CallMsg,
@@ -351,6 +351,7 @@ mod tests {
         }
     }
 
+    #[derive(Default)]
     struct WellBehavedTask;
 
     #[derive(Clone)]
@@ -365,10 +366,6 @@ mod tests {
         type State = CountState;
         type Error = ();
 
-        fn new() -> Self {
-            Self {}
-        }
-
         async fn handle_call(
             &mut self,
             message: Self::CallMsg,

concurrency/src/tasks/stream_tests.rs

@@ -8,6 +8,7 @@ use crate::tasks::{
 
 type SummatoryHandle = GenServerHandle<Summatory>;
 
+#[derive(Default)]
 struct Summatory;
 
 type SummatoryState = u16;
@@ -32,10 +33,6 @@ impl GenServer for Summatory {
     type State = SummatoryState;
     type Error = ();
 
-    fn new() -> Self {
-        Self
-    }
-
     async fn handle_cast(
         &mut self,
         message: Self::CastMsg,

concurrency/src/tasks/timer_tests.rs

@@ -28,6 +28,7 @@ enum RepeaterOutMessage {
     Count(i32),
 }
 
+#[derive(Default)]
 struct Repeater;
 
 impl Repeater {
@@ -53,10 +54,6 @@ impl GenServer for Repeater {
     type State = RepeaterState;
     type Error = ();
 
-    fn new() -> Self {
-        Self
-    }
-
     async fn init(
         &mut self,
         handle: &RepeaterHandle,
@@ -157,6 +154,7 @@ enum DelayedOutMessage {
     Count(i32),
 }
 
+#[derive(Default)]
 struct Delayed;
 
 impl Delayed {
@@ -179,10 +177,6 @@ impl GenServer for Delayed {
     type State = DelayedState;
     type Error = ();
 
-    fn new() -> Self {
-        Self
-    }
-
     async fn handle_call(
         &mut self,
         message: Self::CallMsg,

concurrency/src/threads/gen_server.rs

@@ -83,15 +83,17 @@ pub enum CastResponse<G: GenServer> {
 
 pub trait GenServer
 where
-    Self: Send + Sized,
+    Self: Default + Send + Sized,
 {
     type CallMsg: Clone + Send + Sized;
     type CastMsg: Clone + Send + Sized;
     type OutMsg: Send + Sized;
     type State: Clone + Send;
     type Error: Debug;
 
-    fn new() -> Self;
+    fn new() -> Self {
+        Self::default()
+    }
 
     fn start(initial_state: Self::State) -> GenServerHandle<Self> {
         GenServerHandle::new(initial_state)

concurrency/src/threads/timer_tests.rs

@@ -28,6 +28,7 @@ enum RepeaterOutMessage {
     Count(i32),
 }
 
+#[derive(Default)]
 struct Repeater;
 
 impl Repeater {
@@ -47,10 +48,6 @@ impl GenServer for Repeater {
     type State = RepeaterState;
     type Error = ();
 
-    fn new() -> Self {
-        Self
-    }
-
     fn init(
         &mut self,
         handle: &RepeaterHandle,
@@ -147,6 +144,7 @@ enum DelayedOutMessage {
     Count(i32),
 }
 
+#[derive(Default)]
 struct Delayed;
 
 impl Delayed {
@@ -162,10 +160,6 @@ impl GenServer for Delayed {
     type State = DelayedState;
     type Error = ();
 
-    fn new() -> Self {
-        Self
-    }
-
     fn handle_call(
         &mut self,
         _message: Self::CallMsg,

examples/bank/src/server.rs

@@ -11,6 +11,7 @@ type MsgResult = Result<OutMessage, BankError>;
 type BankHandle = GenServerHandle<Bank>;
 type BankState = HashMap<String, i32>;
 
+#[derive(Default)]
 pub struct Bank {}
 
 impl Bank {
@@ -50,10 +51,6 @@ impl GenServer for Bank {
     type Error = BankError;
     type State = BankState;
 
-    fn new() -> Self {
-        Self {}
-    }
-
     // Initializing "main" account with 1000 in balance to test init() callback.
     async fn init(
         &mut self,

examples/bank_threads/src/server.rs

@@ -11,6 +11,7 @@ type MsgResult = Result<OutMessage, BankError>;
 type BankHandle = GenServerHandle<Bank>;
 type BankState = HashMap<String, i32>;
 
+#[derive(Default)]
 pub struct Bank {}
 
 impl Bank {
@@ -46,10 +47,6 @@ impl GenServer for Bank {
     type Error = BankError;
     type State = BankState;
 
-    fn new() -> Self {
-        Self {}
-    }
-
     // Initializing "main" account with 1000 in balance to test init() callback.
     fn init(
         &mut self,

examples/blocking_genserver/main.rs

@@ -6,7 +6,8 @@ use spawned_concurrency::tasks::{
     CallResponse, CastResponse, GenServer, GenServerHandle, send_after,
 };
 
-// We test a scenario with a badly behaved task
+// We test a scenario with a badly behaved task#[derive(Default)]
+#[derive(Default)]
 struct BadlyBehavedTask;
 
 #[derive(Clone)]
@@ -26,10 +27,6 @@ impl GenServer for BadlyBehavedTask {
     type State = ();
     type Error = ();
 
-    fn new() -> Self {
-        Self {}
-    }
-
     async fn handle_call(
         &mut self,
         _: Self::CallMsg,
@@ -53,6 +50,7 @@ impl GenServer for BadlyBehavedTask {
     }
 }
 
+#[derive(Default)]
 struct WellBehavedTask;
 
 #[derive(Clone)]
@@ -67,10 +65,6 @@ impl GenServer for WellBehavedTask {
     type State = CountState;
     type Error = ();
 
-    fn new() -> Self {
-        Self {}
-    }
-
     async fn handle_call(
         &mut self,
         message: Self::CallMsg,

examples/name_server/src/server.rs

@@ -10,6 +10,7 @@ use crate::messages::{NameServerInMessage as InMessage, NameServerOutMessage as
 type NameServerHandle = GenServerHandle<NameServer>;
 type NameServerState = HashMap<String, String>;
 
+#[derive(Default)]
 pub struct NameServer {}
 
 impl NameServer {
@@ -35,10 +36,6 @@ impl GenServer for NameServer {
     type Error = std::fmt::Error;
     type State = NameServerState;
 
-    fn new() -> Self {
-        Self {}
-    }
-
     async fn handle_call(
         &mut self,
         message: Self::CallMsg,

examples/name_server_with_error/src/server.rs

@@ -11,6 +11,7 @@ use crate::messages::{NameServerInMessage as InMessage, NameServerOutMessage as
 type NameServerHandle = GenServerHandle<NameServer>;
 type NameServerState = HashMap<String, String>;
 
+#[derive(Default)]
 pub struct NameServer {}
 
 impl NameServer {
@@ -37,10 +38,6 @@ impl GenServer for NameServer {
     type Error = std::fmt::Error;
     type State = NameServerState;
 
-    fn new() -> Self {
-        NameServer {}
-    }
-
     async fn handle_call(
         &mut self,
         message: Self::CallMsg,

examples/updater/src/server.rs

@@ -16,6 +16,7 @@ pub struct UpdateServerState {
     pub periodicity: Duration,
     pub timer_token: Option<CancellationToken>,
 }
+#[derive(Default)]
 pub struct UpdaterServer {}
 
 impl GenServer for UpdaterServer {
@@ -25,10 +26,6 @@ impl GenServer for UpdaterServer {
     type Error = std::fmt::Error;
     type State = UpdateServerState;
 
-    fn new() -> Self {
-        Self {}
-    }
-
     // Initializing GenServer to start periodic checks.
     async fn init(
         &mut self,

examples/updater_threads/src/server.rs

@@ -15,6 +15,7 @@ pub struct UpdateServerState {
     pub url: String,
     pub periodicity: Duration,
 }
+#[derive(Default)]
 pub struct UpdaterServer {}
 
 impl GenServer for UpdaterServer {
@@ -24,10 +25,6 @@ impl GenServer for UpdaterServer {
     type Error = std::fmt::Error;
     type State = UpdateServerState;
 
-    fn new() -> Self {
-        Self {}
-    }
-
     // Initializing GenServer to start periodic checks.
     fn init(
         &mut self,