1 files changed, 89 insertions, 0 deletions
diff --git a/container-search/src/main/java/com/yahoo/fs4/mplex/ConnectionPool.java b/container-search/src/main/java/com/yahoo/fs4/mplex/ConnectionPool.java
new file mode 100644
index 00000000000..f39df0d5cec
--- /dev/null
+++ b/container-search/src/main/java/com/yahoo/fs4/mplex/ConnectionPool.java
@@ -0,0 +1,89 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.fs4.mplex;
+
+import java.util.Queue;
+import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.logging.Logger;
+import java.util.Iterator;
+import java.util.Timer;
+import java.util.TimerTask;
+
+import com.yahoo.log.LogLevel;
+/**
+ * Pool of FS4 connections.
+ *
+ * @author tonytv
+ */
+public class ConnectionPool {
+    final static int CLEANINGPERIOD = 1000; // Execute every second
+    private final Queue<FS4Connection> connections = new ConcurrentLinkedQueue<>();
+    private final AtomicInteger activeConnections = new AtomicInteger(0);
+    private final AtomicInteger passiveConnections = new AtomicInteger(0);
+    private static final Logger log = Logger.getLogger(ConnectionPool.class.getName());
+
+    class PoolCleanerTask extends TimerTask {
+        private final ConnectionPool connectionPool;
+        public PoolCleanerTask(ConnectionPool connectionPool) {
+            this.connectionPool = connectionPool;
+        }
+
+        public void run() {
+            try {
+                connectionPool.dropInvalidConnections();
+            } catch (Exception e) {
+                log.log(LogLevel.WARNING,
+                        "Caught exception in connection pool cleaner, ignoring.",
+                        e);
+            }
+        }
+    }
+
+    public ConnectionPool() {
+    }
+
+    public ConnectionPool(Timer timer) {
+        timer.schedule(new PoolCleanerTask(this), CLEANINGPERIOD, CLEANINGPERIOD);
+    }
+
+    private void dropInvalidConnections() {
+        for (Iterator<FS4Connection> i = connections.iterator(); i.hasNext();) {
+            FS4Connection connection = i.next();
+            if (!connection.isValid()) {
+                i.remove();
+            }
+        }
+    }
+
+    private FS4Connection registerAsActiveIfNonZero(FS4Connection connection) {
+        activeConnections.incrementAndGet();
+        passiveConnections.decrementAndGet();
+        return connection;
+    }
+
+    public FS4Connection getConnection() {
+        return registerAsActiveIfNonZero(connections.poll());
+    }
+
+    void releaseConnection(FS4Connection connection) {
+        assert(connection != null);
+        activeConnections.decrementAndGet();
+        if (connection.isValid()) {
+            passiveConnections.incrementAndGet();
+            connections.add(connection);
+        }
+    }
+
+    void createdConnection() {
+        activeConnections.incrementAndGet();
+    }
+
+    int activeConnections() {
+        return activeConnections.get();
+    }
+
+    //unused connections in the pool
+    int passiveConnections() {
+        return passiveConnections.get();
+    }
+}