add chain of responsibility

Author: envision-sz

Cargo.lock

@@ -3,5 +3,6 @@ members = [
     "composite",
     "bridge_pattern",
     "abstract_factory",
-    "factory_method"
+    "factory_method",
+    "chain_of_responsibility"
 ]

Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "chain_of_responsibility"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

chain_of_responsibility/Cargo.toml

@@ -0,0 +1,97 @@
+trait Request {}
+
+struct ConcreteRequest;
+impl Request for ConcreteRequest {}
+trait RequestHandler: RequestHandlerClone {
+    fn get_successor(&self) -> Option<Box<dyn RequestHandler>>;
+    fn handle(&self, request: Box<dyn Request>) {
+        match self.get_successor() {
+            Some(successor) => successor.handle(request),
+            None => println!("chain breaks here"),
+        }
+    }
+}
+
+trait RequestHandlerClone {
+    fn clone_box(&self) -> Box<dyn RequestHandler>;
+}
+impl<T> RequestHandlerClone for T
+where
+    T: RequestHandler + Clone + 'static,
+{
+    fn clone_box(&self) -> Box<dyn RequestHandler> {
+        Box::new(self.clone())
+    }
+}
+
+impl Clone for Box<dyn RequestHandler> {
+    fn clone(&self) -> Self {
+        self.clone_box()
+    }
+}
+
+#[derive(Clone)]
+struct Widget {
+    successor: Option<Box<dyn RequestHandler>>,
+}
+
+impl RequestHandler for Widget {
+    fn get_successor(&self) -> Option<Box<dyn RequestHandler>> {
+        self.successor.clone()
+    }
+
+    fn handle(&self, _request: Box<dyn Request>) {
+        println!("handler in Widget");
+    }
+}
+
+#[derive(Clone)]
+struct Application {
+    successor: Option<Box<dyn RequestHandler>>,
+}
+
+impl RequestHandler for Application {
+    fn get_successor(&self) -> Option<Box<dyn RequestHandler>> {
+        self.successor.clone()
+    }
+
+    fn handle(&self, _request: Box<dyn Request>) {
+        println!("handler in application")
+    }
+}
+
+#[derive(Clone)]
+struct LazyOne {
+    successor: Option<Box<dyn RequestHandler>>,
+}
+
+impl RequestHandler for LazyOne {
+    fn get_successor(&self) -> Option<Box<dyn RequestHandler>> {
+        self.successor.clone()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{Application, ConcreteRequest, LazyOne, RequestHandler, Widget};
+
+    #[test]
+    fn create_success_chain() {
+        let application = Application { successor: None };
+        let widget = Widget {
+            successor: Some(Box::new(application)),
+        };
+        let request = Box::new(ConcreteRequest);
+        widget.handle(request);
+    }
+
+    #[test]
+    fn create_break_chain() {
+        let widget = Widget { successor: None };
+        let lazy_one = LazyOne {
+            successor: Some(Box::new(widget)),
+        };
+        let request = Box::new(ConcreteRequest);
+        lazy_one.handle(request);
+    }
+}

chain_of_responsibility/src/lib.rs

@@ -1 +1 @@
-{"rustc_fingerprint":7405054423634608984,"outputs":{"931469667778813386":{"success":true,"status":"","code":0,"stdout":"___\nlib___.rlib\nlib___.so\nlib___.so\nlib___.a\nlib___.so\n/home/siliang/.rustup/toolchains/stable-x86_64-unknown-linux-gnu\ndebug_assertions\nproc_macro\ntarget_arch=\"x86_64\"\ntarget_endian=\"little\"\ntarget_env=\"gnu\"\ntarget_family=\"unix\"\ntarget_feature=\"fxsr\"\ntarget_feature=\"sse\"\ntarget_feature=\"sse2\"\ntarget_os=\"linux\"\ntarget_pointer_width=\"64\"\ntarget_vendor=\"unknown\"\nunix\n","stderr":""},"17598535894874457435":{"success":true,"status":"","code":0,"stdout":"rustc 1.56.1 (59eed8a2a 2021-11-01)\nbinary: rustc\ncommit-hash: 59eed8a2aac0230a8b53e89d4e99d55912ba6b35\ncommit-date: 2021-11-01\nhost: x86_64-unknown-linux-gnu\nrelease: 1.56.1\nLLVM version: 13.0.0\n","stderr":""},"2797684049618456168":{"success":false,"status":"exit status: 1","code":1,"stdout":"","stderr":"error: `-Csplit-debuginfo` is unstable on this platform\n\n"},"15537503139010883884":{"success":true,"status":"","code":0,"stdout":"___\nlib___.rlib\nlib___.so\nlib___.so\nlib___.a\nlib___.so\n","stderr":""}},"successes":{}}
+{"rustc_fingerprint":7405054423634608984,"outputs":{"17598535894874457435":{"success":true,"status":"","code":0,"stdout":"rustc 1.56.1 (59eed8a2a 2021-11-01)\nbinary: rustc\ncommit-hash: 59eed8a2aac0230a8b53e89d4e99d55912ba6b35\ncommit-date: 2021-11-01\nhost: x86_64-unknown-linux-gnu\nrelease: 1.56.1\nLLVM version: 13.0.0\n","stderr":""},"931469667778813386":{"success":true,"status":"","code":0,"stdout":"___\nlib___.rlib\nlib___.so\nlib___.so\nlib___.a\nlib___.so\n/home/siliang/.rustup/toolchains/stable-x86_64-unknown-linux-gnu\ndebug_assertions\nproc_macro\ntarget_arch=\"x86_64\"\ntarget_endian=\"little\"\ntarget_env=\"gnu\"\ntarget_family=\"unix\"\ntarget_feature=\"fxsr\"\ntarget_feature=\"sse\"\ntarget_feature=\"sse2\"\ntarget_os=\"linux\"\ntarget_pointer_width=\"64\"\ntarget_vendor=\"unknown\"\nunix\n","stderr":""},"2797684049618456168":{"success":false,"status":"exit status: 1","code":1,"stdout":"","stderr":"error: `-Csplit-debuginfo` is unstable on this platform\n\n"},"15537503139010883884":{"success":true,"status":"","code":0,"stdout":"___\nlib___.rlib\nlib___.so\nlib___.so\nlib___.a\nlib___.so\n","stderr":""}},"successes":{}}

target/.rustc_info.json

@@ -0,0 +1 @@
+7a79fa9567a51e5a

target/debug/.fingerprint/composite-86278353ed196e19/output-test-lib-composite

@@ -0,0 +1 @@
+e04aad9e5b4e1988