[Add] LockerMap, Locker 增加Locker锁对象和LockerMap锁对象存储;

[Change] CacheStoreCentral 将synchronized所使用的的锁对象由String(常量池)转换成Locker<K>以尝试减少内存占用;

src/main/java/net/lamgc/cgj/util/Locker.java

@@ -0,0 +1,64 @@
+package net.lamgc.cgj.util;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+public final class Locker<K> {
+
+    private final LockerMap<K> fromMap;
+
+    private final K key;
+
+    private final boolean autoDestroy;
+
+    private final AtomicInteger lockCount = new AtomicInteger(0);
+
+    /**
+     * 构造一个锁对象
+     * @param map 所属LockerMap
+     * @param key 所属Key
+     */
+    Locker(LockerMap<K> map, K key, boolean autoDestroy) {
+        this.fromMap = map;
+        this.key = key;
+        this.autoDestroy = autoDestroy;
+    }
+
+    /**
+     * 上锁
+     */
+    public void lock() {
+        lockCount.incrementAndGet();
+    }
+
+    /**
+     * 解锁
+     */
+    public void unlock() {
+        int newValue = lockCount.decrementAndGet();
+        if(newValue <= 0 && autoDestroy) {
+            destroy();
+        }
+    }
+
+    /**
+     * 获取锁对象所属Key
+     */
+    public K getKey() {
+        return key;
+    }
+
+    /**
+     * 销毁锁对象
+     */
+    public void destroy() {
+        fromMap.destroyLocker(this);
+    }
+
+    @Override
+    public String toString() {
+        return "Locker{" +
+                "fromMap=" + fromMap +
+                ", key=" + key +
+                '}';
+    }
+}

src/main/java/net/lamgc/cgj/util/LockerMap.java

@@ -0,0 +1,31 @@
+package net.lamgc.cgj.util;
+
+import java.util.HashMap;
+
+public class LockerMap<K> {
+
+    private final HashMap<K, Locker<K>> lockerHashMap = new HashMap<>();
+
+    /**
+     * 创建锁
+     * @param key Key
+     * @return 如果Key所属锁存在, 则返回对应锁, 否则返回新锁
+     */
+    public Locker<K> createLocker(K key, boolean autoDestroy) {
+        if(lockerHashMap.containsKey(key)) {
+            return lockerHashMap.get(key);
+        }
+        Locker<K> newLocker = new Locker<>(this, key, autoDestroy);
+        lockerHashMap.put(key, newLocker);
+        return newLocker;
+    }
+
+    /**
+     * 销毁锁
+     * @param locker 锁对象
+     */
+    public void destroyLocker(Locker<K> locker) {
+        lockerHashMap.remove(locker.getKey());
+    }
+
+}