rrd4j: Merge in upstream changes part 4

add file missing from previous checkin

apps/jrobin/java/src/org/rrd4j/graph/TimeUnit.java

@@ -0,0 +1,71 @@
+package org.rrd4j.graph;
+
+import java.util.Calendar;
+
+import static org.rrd4j.graph.RrdGraphConstants.HH_MM;
+
+public enum TimeUnit {
+    SECOND {
+        @Override
+        public String getLabel() {
+            return "s";
+        }
+    },
+    MINUTE {
+        @Override
+        public String getLabel() {
+            return HH_MM;
+        }
+    },
+    HOUR {
+        @Override
+        public String getLabel() {
+            return HH_MM;
+        }
+    },
+    DAY {
+        @Override
+        public String getLabel() {
+            return "EEE dd";
+        }
+    },
+    WEEK {
+        @Override
+        public String getLabel() {
+            return "'Week 'w";
+        }
+    },
+    MONTH {
+        @Override
+        public String getLabel() {
+            return "MMM";
+        }
+    },
+    YEAR {
+        @Override
+        public String getLabel() {
+            return "yy";
+        }
+    };
+    public abstract String getLabel();
+    public static TimeUnit resolveUnit(int unitKey) {
+        switch (unitKey) {
+        case Calendar.SECOND:
+            return SECOND;
+        case Calendar.MINUTE:
+            return MINUTE;
+        case Calendar.HOUR_OF_DAY:
+            return HOUR;
+        case Calendar.DAY_OF_MONTH:
+            return DAY;
+        case Calendar.WEEK_OF_YEAR:
+            return WEEK;
+        case Calendar.MONTH:
+            return MONTH;
+        case Calendar.YEAR:
+            return YEAR;
+        default:
+            throw new IllegalArgumentException("Unidentified key " + unitKey);
+        }
+    }
+}