--- /dev/null
+/*
+ * Copyright (c) 2013 Cisco Systems, Inc. and others. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+
+package org.opendaylight.controller.protocol_plugin.openflow.core.internal;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.CountDownLatch;
+
+import org.opendaylight.controller.protocol_plugin.openflow.core.ISwitch;
+import org.openflow.protocol.OFBarrierRequest;
+import org.openflow.protocol.OFError;
+import org.openflow.protocol.OFMessage;
+
+/**
+ * This class implements synchronous operations on message send to a switch. If
+ * syncRequest is set to true, it sends the requested message to the switch
+ * followed by a Barrier request message. It returns the result once it gets the
+ * reply from the switch or after a timeout. If the protocol does not dictate
+ * the switch to reply the processing status for a particular message, the
+ * Barrier request forces the switch to reply saying whether or not the message
+ * processing was successful for messages sent to the switch up to this point.
+ * If syncRequest is false, it simply skips the message send and just waits for
+ * the response back.
+ */
+public class SynchronousMessage implements Callable<Object> {
+ private ISwitch sw;
+ private Integer xid;
+ private OFMessage syncMsg;
+ protected CountDownLatch latch;
+ private Object result;
+ private boolean syncRequest;
+
+ public SynchronousMessage(ISwitch sw, Integer xid, OFMessage msg,
+ boolean syncRequest) {
+ this.sw = sw;
+ this.xid = xid;
+ syncMsg = msg;
+ latch = new CountDownLatch(1);
+ result = null;
+ this.syncRequest = syncRequest;
+ }
+
+ @Override
+ public Object call() throws Exception {
+ /*
+ * Send out message only if syncRequest is set to true. Otherwise, just
+ * wait for the Barrier response back.
+ */
+ if (syncRequest) {
+ sw.asyncSend(syncMsg, xid);
+ if (!(syncMsg instanceof OFBarrierRequest)) {
+ OFBarrierRequest barrierMsg = new OFBarrierRequest();
+ sw.asyncSend(barrierMsg, xid);
+ }
+ }
+ latch.await();
+ return result;
+ }
+
+ public Integer getXid() {
+ return this.xid;
+ }
+
+ public void wakeup() {
+ this.latch.countDown();
+ }
+
+ public void wakeup(OFError e) {
+ result = e;
+ wakeup();
+ }
+
+}
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