+/*
+ * Copyright (c) 2017 Pantheon Technologies, s.r.o. 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.cluster.access.commands;
+
+import com.google.common.annotations.Beta;
+import org.opendaylight.controller.cluster.access.concepts.RequestException;
+
+/**
+ * A {@link RequestException} indicating that the backend has received a RequestEnvelope whose sequence does not match
+ * the next expected sequence. This can happen during leader transitions, when a part of the stream is rejected because
+ * the backend is not the leader and it transitions to being a leader with old stream messages still being present.
+ *
+ * @author Robert Varga
+ */
+@Beta
+public final class OutOfSequenceEnvelopeException extends RequestException {
+ private static final long serialVersionUID = 1L;
+
+ public OutOfSequenceEnvelopeException(final long expectedEnvelope) {
+ super("Expecting envelope " + Long.toUnsignedString(expectedEnvelope));
+ }
+
+ @Override
+ public boolean isRetriable() {
+ return true;
+ }
+}