Task/hp index hole investigation (#49)

* re #2702: Renaming the field index hole to a index field gap
* Ensure date range in from beginning of day to end of day for index field
holes
* Use java.time library instead of Calendar.  Added test cases for index
field hole
* For old style index markers, marking the previous day as as the boundary
because we can assume the current day is only partially indexed

Author: ivakegg

src/main/java/datawave/query/model/FieldIndexHole.java renamed to src/main/java/datawave/query/model/IndexFieldHole.java

@@ -1,5 +1,7 @@
 package datawave.query.model;
 
+import java.time.Instant;
+import java.time.temporal.ChronoUnit;
 import java.util.Collection;
 import java.util.Comparator;
 import java.util.Date;
@@ -16,21 +18,52 @@
  * This class represents a set of calculated field index holes for a given fieldName and datatype. A field index hole is effectively a date where a frequency
  * row was seen, but an index and/or reversed indexed row was not.
  */
-public class FieldIndexHole {
+public class IndexFieldHole {
 
     private final String fieldName;
     private final String datatype;
     private final SortedSet<Pair<Date,Date>> dateRanges;
+    private static long DAY_MILLIS = 1000L * 60 * 60 * 24;
 
-    public FieldIndexHole(String fieldName, String dataType, Collection<Pair<Date,Date>> holes) {
+    public IndexFieldHole(String fieldName, String dataType, Collection<Pair<Date,Date>> holes) {
         this.fieldName = fieldName;
         this.datatype = dataType;
-        // Ensure the date range set is immutable.
+        // Ensure the date range set is immutable, and starts at the beginning of the start date, and ends at the end of the end date
         ImmutableSortedSet.Builder<Pair<Date,Date>> builder = new ImmutableSortedSet.Builder<>(Comparator.naturalOrder());
-        holes.forEach(p -> builder.add(new ImmutablePair<>(p.getLeft(), p.getRight())));
+        holes.forEach(p -> builder.add(new ImmutablePair<>(floor(p.getLeft()), ceil(p.getRight()))));
         dateRanges = builder.build();
     }
 
+    /**
+     * return the date instant at 00:00:00
+     * 
+     * @param d
+     * @return instant of d with time reset to 00:00:00
+     */
+    private static Instant floorInstant(Date d) {
+        return Instant.ofEpochMilli(d.getTime()).truncatedTo(ChronoUnit.DAYS);
+    }
+    
+    /**
+     * return the date at 00:00:00
+     * 
+     * @param d
+     * @return d with time reset to 00:00:00
+     */
+    private static Date floor(Date d) {
+        return Date.from(floorInstant(d));
+    }
+    
+    /**
+     * return the date at 23:59:59
+     * 
+     * @param d
+     * @return d with time reset to 23:59:59
+     */
+    private static Date ceil(Date d) {
+        return Date.from(floorInstant(d).plusMillis(DAY_MILLIS - 1));
+    }
+    
     /**
      * Return the field name.
      * 
@@ -50,7 +83,7 @@ public String getDatatype() {
     }
 
     /**
-     * Returns the set of date ranges that span over field index holes for the fieldName and datatype of this {@link FieldIndexHole}. Each date range represents
+     * Returns the set of date ranges that span over field index holes for the fieldName and datatype of this {@link IndexFieldHole}. Each date range represents
      * a span of consecutive days for which a frequency row exist, but an index row does not. All date ranges are start(inclusive)-end(inclusive).
      * 
      * @return the date ranges
@@ -67,7 +100,7 @@ public boolean equals(Object o) {
         if (o == null || getClass() != o.getClass()) {
             return false;
         }
-        FieldIndexHole indexHole = (FieldIndexHole) o;
+        IndexFieldHole indexHole = (IndexFieldHole) o;
         return Objects.equals(fieldName, indexHole.fieldName) && Objects.equals(datatype, indexHole.datatype)
                         && Objects.equals(dateRanges, indexHole.dateRanges);
     }
@@ -79,7 +112,7 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        return new StringJoiner(", ", FieldIndexHole.class.getSimpleName() + "[", "]").add("fieldName='" + fieldName + "'").add("dataType='" + datatype + "'")
+        return new StringJoiner(", ", IndexFieldHole.class.getSimpleName() + "[", "]").add("fieldName='" + fieldName + "'").add("dataType='" + datatype + "'")
                         .add("dateRanges=" + dateRanges).toString();
     }
 }