Add data version mechanism in local ConfigCache

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

Author: sczyh30

src/main/java/io/opensergo/subscribe/SubscribedConfigCache.java

@@ -16,24 +16,40 @@
 package io.opensergo.subscribe;
 
 import java.util.List;
+import java.util.Optional;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 
 /**
  * @author Eric Zhao
+ * @author xzd
  */
 public class SubscribedConfigCache {
 
-    private final ConcurrentMap<SubscribeKey, List<Object>> dataMap = new ConcurrentHashMap<>();
+    private final ConcurrentMap<SubscribeKey, SubscribedData> dataMap = new ConcurrentHashMap<>();
 
-    public void updateData(SubscribeKey key, List<Object> data) {
-        dataMap.put(key, data);
+    public void updateData(SubscribeKey key, Object data, long version) {
+        // TODO: guarantee the latest version
+        dataMap.put(key, new SubscribedData(version, data));
     }
 
-    public List<Object> getDataFor(SubscribeKey key) {
+    public SubscribedData getDataFor(SubscribeKey key) {
         if (key == null) {
             return null;
         }
         return dataMap.get(key);
     }
+
+    public Optional<Long> getDataVersionFor(SubscribeKey key) {
+        SubscribedData d = getDataFor(key);
+        return Optional.ofNullable(getDataFor(key)).map(SubscribedData::getVersion);
+    }
+
+    public <T> List<T> getDataListFor(SubscribeKey key, Class<T> clazz) {
+        SubscribedData d = getDataFor(key);
+        if (d == null || d.getData() == null) {
+            return null;
+        }
+        return (List<T>) d.getData();
+    }
 }

src/main/java/io/opensergo/subscribe/SubscribedData.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2022, OpenSergo Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.opensergo.subscribe;
+
+/**
+ * @author Eric Zhao
+ */
+public class SubscribedData {
+
+    private long version;
+    private Object data;
+
+    public SubscribedData() {}
+
+    public SubscribedData(long version, Object data) {
+        this.version = version;
+        this.data = data;
+    }
+
+    public long getVersion() {
+        return version;
+    }
+
+    public SubscribedData setVersion(long version) {
+        this.version = version;
+        return this;
+    }
+
+    public Object getData() {
+        return data;
+    }
+
+    public SubscribedData setData(Object data) {
+        this.data = data;
+        return this;
+    }
+
+    @Override
+    public String toString() {
+        return "SubscribedData{" +
+            "version='" + version + '\'' +
+            ", data=" + data +
+            '}';
+    }
+}