From aae799f19ad577527bce3520471ccf3b44ec621e Mon Sep 17 00:00:00 2001
From: deibudei <deibudei@noreply.gitcode.com>
Date: Wed, 6 May 2026 00:26:02 +0800
Subject: [PATCH] =?UTF-8?q?fix(repair):=20=E4=BF=AE=E5=A4=8D=20InventorySe?=
 =?UTF-8?q?rvice.deduct=20=E7=9A=84=E5=B9=B6=E5=8F=91=E7=AB=9E=E6=80=81?=
 =?UTF-8?q?=E6=9D=A1=E4=BB=B6?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 target-service/files/welcome.txt              |  1 +
 .../repository/InventoryRepository.java       | 22 +++++++++++++++++++
 .../service/InventoryService.java             | 15 ++-----------
 3 files changed, 25 insertions(+), 13 deletions(-)
 create mode 100644 target-service/files/welcome.txt

diff --git a/target-service/files/welcome.txt b/target-service/files/welcome.txt
new file mode 100644
index 0000000..13d6eec
--- /dev/null
+++ b/target-service/files/welcome.txt
@@ -0,0 +1 @@
+hello from storage
\ No newline at end of file
diff --git a/target-service/src/main/java/com/example/targetservice/repository/InventoryRepository.java b/target-service/src/main/java/com/example/targetservice/repository/InventoryRepository.java
index adc83df..7c00b00 100644
--- a/target-service/src/main/java/com/example/targetservice/repository/InventoryRepository.java
+++ b/target-service/src/main/java/com/example/targetservice/repository/InventoryRepository.java
@@ -32,4 +32,26 @@ public InventoryItem save(InventoryItem item) {
     public int stock(String sku) {
         return findBySku(sku).stock();
     }
+
+    /**
+     * Atomically deducts stock for a given SKU.
+     * Uses ConcurrentHashMap.compute to ensure read-check-write atomicity.
+     * @throws IllegalArgumentException if SKU not found or insufficient stock
+     */
+    public InventoryItem deductStock(String sku, int quantity) {
+        if (quantity <= 0) {
+            throw new IllegalArgumentException("quantity must be positive, but got: " + quantity);
+        }
+        return store.compute(sku, (key, item) -> {
+            if (item == null) {
+                throw new IllegalArgumentException("SKU not found: " + sku);
+            }
+            if (item.stock() < quantity) {
+                throw new IllegalArgumentException(
+                        "insufficient stock for " + sku + ": have " + item.stock() + ", need " + quantity);
+            }
+            return new InventoryItem(item.sku(), item.name(),
+                    item.stock() - quantity, item.reserved() + quantity);
+        });
+    }
 }
diff --git a/target-service/src/main/java/com/example/targetservice/service/InventoryService.java b/target-service/src/main/java/com/example/targetservice/service/InventoryService.java
index d20a46c..bbe6caf 100644
--- a/target-service/src/main/java/com/example/targetservice/service/InventoryService.java
+++ b/target-service/src/main/java/com/example/targetservice/service/InventoryService.java
@@ -14,21 +14,10 @@ public InventoryService(InventoryRepository repository) {
     }
 
     /**
-     * Deducts stock for a given SKU.
-     * BUG: No synchronization — concurrent calls can over-sell inventory.
+     * Deducts stock for a given SKU using atomic operation.
      */
     public InventoryItem deduct(String sku, int quantity) {
-        if (quantity <= 0) {
-            throw new IllegalArgumentException("quantity must be positive, but got: " + quantity);
-        }
-        InventoryItem item = repository.findBySku(sku);
-        if (item.stock() < quantity) {
-            throw new IllegalArgumentException(
-                    "insufficient stock for " + sku + ": have " + item.stock() + ", need " + quantity);
-        }
-        InventoryItem updated = new InventoryItem(item.sku(), item.name(),
-                item.stock() - quantity, item.reserved() + quantity);
-        return repository.save(updated);
+        return repository.deductStock(sku, quantity);
     }
 
     public InventoryItem getStock(String sku) {