src/org/redkale/net/Transport.java

@@ -10,6 +10,7 @@ import java.lang.ref.WeakReference;
 import java.net.*;
 import java.nio.ByteBuffer;
 import java.nio.channels.*;
+import java.sql.SQLException;
 import java.util.*;
 import java.util.concurrent.*;
 import java.util.concurrent.atomic.*;
@@ -56,6 +57,9 @@ public final class Transport {
     //负载均衡策略
     protected final TransportStrategy strategy;
 
+    //连接上限， 为null表示无限制
+    protected Semaphore semaphore;
+
     protected Transport(String name, TransportFactory factory, final ObjectPool<ByteBuffer> transportBufferPool,
         final AsynchronousChannelGroup transportChannelGroup, final SSLContext sslContext, final InetSocketAddress clientAddress,
         final Collection<InetSocketAddress> addresses, final TransportStrategy strategy) {
@@ -78,6 +82,14 @@ public final class Transport {
         updateRemoteAddresses(addresses);
     }
 
+    public Semaphore getSemaphore() {
+        return semaphore;
+    }
+
+    public void setSemaphore(Semaphore semaphore) {
+        this.semaphore = semaphore;
+    }
+
     public final InetSocketAddress[] updateRemoteAddresses(final Collection<InetSocketAddress> addresses) {
         final TransportNode[] oldNodes = this.transportNodes;
         synchronized (this) {
@@ -210,6 +222,44 @@ public final class Transport {
         return tcp;
     }
 
+    protected CompletableFuture<AsyncConnection> pollAsync(TransportNode node, SocketAddress addr, Supplier<CompletableFuture<AsyncConnection>> func, final int count) {
+        if (count >= 5) {
+            CompletableFuture<AsyncConnection> future = new CompletableFuture<>();
+            future.completeExceptionally(new SQLException("create AsyncConnection error"));
+            return future;
+        }
+        final BlockingQueue<AsyncConnection> queue = node.conns;
+        if (!queue.isEmpty()) {
+            AsyncConnection conn;
+            while ((conn = queue.poll()) != null) {
+                if (conn.isOpen()) {
+                    return CompletableFuture.completedFuture(conn);
+                } else {
+                    conn.dispose();
+                }
+            }
+        }
+        if (semaphore != null && !semaphore.tryAcquire()) {
+            return CompletableFuture.supplyAsync(() -> {
+                try {
+                    return queue.poll(1, TimeUnit.SECONDS);
+                } catch (Exception t) {
+                    return null;
+                }
+            }, factory.executor).thenCompose((conn2) -> {
+                if (conn2 != null && conn2.isOpen()) {
+                    return CompletableFuture.completedFuture(conn2);
+                }
+                return pollAsync(node, addr, func, count + 1);
+            });
+        }
+        return func.get().thenApply(conn -> {
+            if (conn != null && semaphore != null) conn.beforeCloseListener((c) -> semaphore.release());
+            return conn;
+        });
+
+    }
+
     public CompletableFuture<AsyncConnection> pollConnection(SocketAddress addr0) {
         if (this.strategy != null) return strategy.pollConnection(addr0, this);
         final TransportNode[] nodes = this.transportNodes;
@@ -230,18 +280,7 @@ public final class Transport {
                 if (node == null) {
                     return AsyncConnection.createTCP(bufferPool, group, sslContext, addr, factory.readTimeoutSeconds, factory.writeTimeoutSeconds);
                 }
-                final BlockingQueue<AsyncConnection> queue = node.conns;
+                return pollAsync(node, addr, () -> AsyncConnection.createTCP(bufferPool, group, sslContext, addr, factory.readTimeoutSeconds, factory.writeTimeoutSeconds), 1);
-                if (!queue.isEmpty()) {
-                    AsyncConnection conn;
-                    while ((conn = queue.poll()) != null) {
-                        if (conn.isOpen()) {
-                            return CompletableFuture.completedFuture(conn);
-                        } else {
-                            conn.dispose();
-                        }
-                    }
-                }
-                return AsyncConnection.createTCP(bufferPool, group, sslContext, addr, factory.readTimeoutSeconds, factory.writeTimeoutSeconds);
             }
 
             //---------------------随机取地址------------------------
@@ -265,11 +304,18 @@ public final class Transport {
                         }
                     }
                 }
+                return pollAsync(one, one.getAddress(), () -> {
                     CompletableFuture future = new CompletableFuture();
-                final AsynchronousSocketChannel channel = AsynchronousSocketChannel.open(group);
+                    AsynchronousSocketChannel channel0 = null;
-                channel.setOption(StandardSocketOptions.TCP_NODELAY, true);
+                    try {
-                channel.setOption(StandardSocketOptions.SO_KEEPALIVE, true);
+                        channel0 = AsynchronousSocketChannel.open(group);
-                channel.setOption(StandardSocketOptions.SO_REUSEADDR, true);
+                        channel0.setOption(StandardSocketOptions.TCP_NODELAY, true);
+                        channel0.setOption(StandardSocketOptions.SO_KEEPALIVE, true);
+                        channel0.setOption(StandardSocketOptions.SO_REUSEADDR, true);
+                    } catch (Exception ex) {
+                        ex.printStackTrace();
+                    }
+                    final AsynchronousSocketChannel channel = channel0;
                     channel.connect(one.address, one, new CompletionHandler<Void, TransportNode>() {
                         @Override
                         public void completed(Void result, TransportNode attachment) {
@@ -304,6 +350,7 @@ public final class Transport {
                         }
                     });
                     return future;
+                }, 1);
             }
             return pollConnection0(nodes, null, now);
         } catch (Exception ex) {