Range/Term query/filter on dates fail to handle numbers properly

When providing a number (milliseconds since epoch, UTC), range and term query/filter don't handle it correctly and convert it to a string, that is then first tried to parse as a date
closes #5969

src/main/java/org/elasticsearch/index/mapper/core/DateFieldMapper.java

@@ -301,6 +301,9 @@ public class DateFieldMapper extends NumberFieldMapper<Long> {
     }
 
     public long parseToMilliseconds(Object value, @Nullable QueryParseContext context, boolean includeUpper) {
+        if (value instanceof Number) {
+            return ((Number) value).longValue();
+        }
         long now = context == null ? System.currentTimeMillis() : context.nowInMillis();
         return includeUpper && roundCeil ? dateMathParser.parseRoundCeil(convertToString(value), now) : dateMathParser.parse(convertToString(value), now);
     }
@@ -335,15 +338,23 @@ public class DateFieldMapper extends NumberFieldMapper<Long> {
         Long lowerVal = null;
         Long upperVal = null;
         if (lowerTerm != null) {
+            if (lowerTerm instanceof Number) {
+                lowerVal = ((Number) lowerTerm).longValue();
+            } else {
                 String value = convertToString(lowerTerm);
                 cache = explicitCaching || !hasNowExpressionWithNoRounding(value);
                 lowerVal = parseToMilliseconds(value, context, false);
             }
+        }
         if (upperTerm != null) {
+            if (upperTerm instanceof Number) {
+                upperVal = ((Number) upperTerm).longValue();
+            } else {
                 String value = convertToString(upperTerm);
                 cache = explicitCaching || !hasNowExpressionWithNoRounding(value);
                 upperVal = parseToMilliseconds(value, context, includeUpper);
             }
+        }
 
         Filter filter =  NumericRangeFilter.newLongRange(
             names.indexName(), precisionStep, lowerVal, upperVal, includeLower, includeUpper
@@ -367,15 +378,23 @@ public class DateFieldMapper extends NumberFieldMapper<Long> {
         Long lowerVal = null;
         Long upperVal = null;
         if (lowerTerm != null) {
+            if (lowerTerm instanceof Number) {
+                lowerVal = ((Number) lowerTerm).longValue();
+            } else {
                 String value = convertToString(lowerTerm);
                 cache = explicitCaching || !hasNowExpressionWithNoRounding(value);
                 lowerVal = parseToMilliseconds(value, context, false);
             }
+        }
         if (upperTerm != null) {
+            if (upperTerm instanceof Number) {
+                upperVal = ((Number) upperTerm).longValue();
+            } else {
                 String value = convertToString(upperTerm);
                 cache = explicitCaching || !hasNowExpressionWithNoRounding(value);
                 upperVal = parseToMilliseconds(value, context, includeUpper);
             }
+        }
 
         Filter filter =  NumericRangeFieldDataFilter.newLongRange(
             (IndexNumericFieldData<?>) fieldData.getForField(this), lowerVal,upperVal, includeLower, includeUpper

src/test/java/org/elasticsearch/search/query/SimpleQueryTests.java

@@ -2155,6 +2155,19 @@ public class SimpleQueryTests extends ElasticsearchIntegrationTest {
         assertSearchHits(searchResponse, "1");
     }
 
+    @Test
+    public void testDateProvidedAsNumber() {
+        createIndex("test");
+        assertAcked(client().admin().indices().preparePutMapping("test").setType("type").setSource("field", "type=date").get());
+        client().prepareIndex("test", "type", "1").setSource("field", -1000000000001L).get();
+        client().prepareIndex("test", "type", "2").setSource("field", -1000000000000L).get();
+        client().prepareIndex("test", "type", "3").setSource("field", -999999999999L).get();
+        refresh();
+
+        assertHitCount(client().prepareCount("test").setQuery(rangeQuery("field").lte(-1000000000000L)).get(), 2);
+        assertHitCount(client().prepareCount("test").setQuery(rangeQuery("field").lte(-999999999999L)).get(), 3);
+    }
+
     @Test
     public void testRangeFilterNoCacheWithNow() throws Exception {
         assertAcked(prepareCreate("test")