Initial implementation of shared test cell warden.

Change-Id: Ia973d514fe1dd11ffe4cdb7c902cc43a9c2eb626
diff --git a/utils/warden/src/main/java/org/onlab/warden/Reservation.java b/utils/warden/src/main/java/org/onlab/warden/Reservation.java
new file mode 100644
index 0000000..59ffe3a
--- /dev/null
+++ b/utils/warden/src/main/java/org/onlab/warden/Reservation.java
@@ -0,0 +1,62 @@
+/*
+ * Copyright 2016 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.onlab.warden;
+
+import static com.google.common.base.Preconditions.checkState;
+
+/**
+ * Cell reservation record.
+ */
+final class Reservation {
+
+    final String cellName;
+    final String userName;
+    final long time;
+    final int duration;
+
+    // Creates a new reservation record
+    Reservation(String cellName, String userName, long time, int duration) {
+        this.cellName = cellName;
+        this.userName = userName;
+        this.time = time;
+        this.duration = duration;
+    }
+
+    /**
+     * Decodes reservation record from the specified line.
+     *
+     * @param line string line
+     */
+    Reservation(String line) {
+        String[] fields = line.trim().split("\t");
+        checkState(fields.length == 4, "Incorrect reservation encoding");
+        this.cellName = fields[0];
+        this.userName = fields[1];
+        this.time = Long.parseLong(fields[2]);
+        this.duration = Integer.parseInt(fields[3]);
+    }
+
+    /**
+     * Encodes reservation record into a string line.
+     *
+     * @return encoded string
+     */
+    String encode() {
+        return String.format("%s\t%s\t%s\t%s\n", cellName, userName, time, duration);
+    }
+
+}