feature: add socket connection pool

src/main/java/org/csource/fastdfs/pool/ConnectionPool.java

@@ -0,0 +1,75 @@
+package org.csource.fastdfs.pool;
+
+import org.csource.fastdfs.TrackerServer;
+
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public class ConnectionPool {
+    /**
+     * key is ip:port, value is ConnectionManager
+     */
+    private final static ConcurrentHashMap<String, ConnectionManager> CP = new ConcurrentHashMap<String, ConnectionManager>();
+
+    public static synchronized ConnectionInfo getConnection(InetSocketAddress socketAddress) throws IOException {
+        if (socketAddress == null) {
+            return null;
+        }
+        String key = getKey(socketAddress);
+        ConnectionManager connectionManager = CP.get(key);
+        if (connectionManager == null) {
+            connectionManager = new ConnectionManager(key);
+            CP.put(key, connectionManager);
+        }
+        return connectionManager.getConnection();
+    }
+
+    /**
+     * release connection
+     */
+    public static void closeConnection(TrackerServer trackerServer) throws IOException {
+        if (trackerServer == null || trackerServer.getInetSocketAddress() == null) {
+            return;
+        }
+        String key = getKey(trackerServer.getInetSocketAddress());
+        if (key != null) {
+            ConnectionManager connectionManager = CP.get(key);
+            connectionManager.closeConnection(new ConnectionInfo(trackerServer.getSocket(), trackerServer.getInetSocketAddress(),trackerServer.getLastAccessTime(),true));
+        } else {
+            trackerServer.close();
+        }
+    }
+
+    public static void freeConnection(TrackerServer trackerServer) throws IOException {
+        if (trackerServer == null || trackerServer.getInetSocketAddress() == null) {
+            return;
+        }
+        String key = getKey(trackerServer.getInetSocketAddress());
+        if (key != null) {
+            ConnectionManager connectionManager = CP.get(key);
+            connectionManager.freeConnection(trackerServer);
+        } else {
+            trackerServer.close();
+        }
+    }
+
+    private static String getKey(InetSocketAddress socketAddress) {
+        if (socketAddress == null) {
+            return null;
+        }
+        return String.format("%s:%s", socketAddress.getHostName(), socketAddress.getPort());
+    }
+    @Override
+    public String toString() {
+        if (!CP.isEmpty()) {
+            StringBuilder builder = new StringBuilder();
+            for (Map.Entry<String, ConnectionManager> managerEntry : CP.entrySet()) {
+                builder.append("key:" + managerEntry.getKey() + " -------- entry:" + managerEntry.getValue() + "\n");
+            }
+            return builder.toString();
+        }
+        return null;
+    }
+}