killbill-aplcache

diff --git a/usage/src/main/java/com/ning/billing/usage/timeline/DateTimeUtils.java b/usage/src/main/java/com/ning/billing/usage/timeline/DateTimeUtils.java
new file mode 100644
index 0000000..e0e5a03
--- /dev/null
+++ b/usage/src/main/java/com/ning/billing/usage/timeline/DateTimeUtils.java
@@ -0,0 +1,32 @@
+/*
+ * Copyright 2010-2012 Ning, Inc.
+ *
+ * Ning licenses this file to you 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 com.ning.billing.usage.timeline;
+
+import org.joda.time.DateTime;
+import org.joda.time.DateTimeZone;
+
+public class DateTimeUtils {
+
+    public static DateTime dateTimeFromUnixSeconds(final int unixTime) {
+        return new DateTime(((long) unixTime) * 1000L, DateTimeZone.UTC);
+    }
+
+    public static int unixSeconds(final DateTime dateTime) {
+        final long millis = dateTime.toDateTime(DateTimeZone.UTC).getMillis();
+        return (int) (millis / 1000L);
+    }
+}

diff --git a/usage/src/test/java/com/ning/billing/usage/timeline/TestDateTimeUtils.java b/usage/src/test/java/com/ning/billing/usage/timeline/TestDateTimeUtils.java
new file mode 100644
index 0000000..fc86f84
--- /dev/null
+++ b/usage/src/test/java/com/ning/billing/usage/timeline/TestDateTimeUtils.java
@@ -0,0 +1,23 @@
+package com.ning.billing.usage.timeline;
+
+import org.joda.time.DateTime;
+import org.joda.time.Seconds;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+import com.ning.billing.util.clock.Clock;
+import com.ning.billing.util.clock.ClockMock;
+
+public class TestDateTimeUtils {
+
+    private final Clock clock = new ClockMock();
+
+    @Test(groups = "fast")
+    public void testRoundTrip() throws Exception {
+        final DateTime utcNow = clock.getUTCNow();
+        final int unixSeconds = DateTimeUtils.unixSeconds(utcNow);
+        final DateTime dateTimeFromUnixSeconds = DateTimeUtils.dateTimeFromUnixSeconds(unixSeconds);
+
+        Assert.assertEquals(Seconds.secondsBetween(dateTimeFromUnixSeconds, utcNow), 0);
+    }
+}