[di-transaction] Wallet と Inventory を trait に

Author: nojima

di-transaction/src/inventory.rs

@@ -2,11 +2,15 @@ use mysql;
 use mysql::params;
 use mysql::prelude::*;
 
-pub struct Inventory {}
+pub trait Inventory {
+    fn add_items(&mut self, tx: &mut mysql::Transaction, amount: i64) -> crate::Result<()>;
+}
+
+pub struct MySqlInventory {}
 
-impl Inventory {
+impl Inventory for MySqlInventory {
     // アイテムを指定された量だけ追加する
-    pub fn add_items(&mut self, tx: &mut mysql::Transaction, amount: i64) -> crate::Result<()> {
+    fn add_items(&mut self, tx: &mut mysql::Transaction, amount: i64) -> crate::Result<()> {
         let user_id: i64 = 1;
         let item_id: i64 = 1;
         let stmt = "\

di-transaction/src/main.rs

@@ -15,8 +15,8 @@ fn main() -> Result<()> {
     let pool = mysql::Pool::new(url)?;
     let mut conn = pool.get_conn()?;
 
-    let mut inventory = Inventory{};
-    let mut wallet = Wallet{};
+    let mut inventory = MySqlInventory{};
+    let mut wallet = MySqlWallet{};
 
     purchase_item(&mut inventory, &mut wallet, &mut conn)?;
 

di-transaction/src/purchase.rs

@@ -6,8 +6,8 @@ use anyhow::anyhow;
 
 // アイテムを購入する
 pub fn purchase_item(
-    inventory: &mut Inventory,
-    wallet: &mut Wallet,
+    inventory: &mut impl Inventory,
+    wallet: &mut impl Wallet,
     conn: &mut mysql::PooledConn
 ) -> crate::Result<()> {
 

di-transaction/src/wallet.rs

@@ -3,11 +3,16 @@ use mysql::params;
 use mysql::prelude::*;
 use anyhow::anyhow;
 
-pub struct Wallet {}
+pub trait Wallet {
+    fn get_balance(&self, tx: &mut mysql::Transaction) -> crate::Result<i64>;
+    fn pay(&mut self, tx: &mut mysql::Transaction, amount: i64) -> crate::Result<()>;
+}
+
+pub struct MySqlWallet {}
 
-impl Wallet {
+impl Wallet for MySqlWallet {
     // 現在の残高を返す
-    pub fn get_balance(&self, tx: &mut mysql::Transaction) -> crate::Result<i64> {
+    fn get_balance(&self, tx: &mut mysql::Transaction) -> crate::Result<i64> {
         let user_id: i64 = 1;
         let query = "\
             SELECT `balance` \
@@ -21,7 +26,7 @@ impl Wallet {
     }
 
     // 残高を減らす
-    pub fn pay(&mut self, tx: &mut mysql::Transaction, amount: i64) -> crate::Result<()> {
+    fn pay(&mut self, tx: &mut mysql::Transaction, amount: i64) -> crate::Result<()> {
         let user_id: i64 = 1;
         let stmt = "\
             UPDATE `wallet` \