Remove JsonBackedExponentialHistogram.java

Author: JonasKunz

libs/exponential-histogram/src/main/java/org/elasticsearch/exponentialhistogram/ExponentialHistogramXContent.java

@@ -21,6 +21,7 @@
 
 package org.elasticsearch.exponentialhistogram;
 
+import org.elasticsearch.core.Nullable;
 import org.elasticsearch.core.Types;
 import org.elasticsearch.xcontent.XContentBuilder;
 import org.elasticsearch.xcontent.XContentParser;
@@ -54,7 +55,11 @@ public class ExponentialHistogramXContent {
      * @param histogram the ExponentialHistogram to serialize
      * @throws IOException if the XContentBuilder throws an IOException
      */
-    public static void serialize(XContentBuilder builder, ExponentialHistogram histogram) throws IOException {
+    public static void serialize(XContentBuilder builder, @Nullable ExponentialHistogram histogram) throws IOException {
+        if (histogram == null) {
+            builder.nullValue();
+            return;
+        }
         builder.startObject();
 
         builder.field(SCALE_FIELD, histogram.scale());
@@ -118,6 +123,12 @@ private static void writeBuckets(XContentBuilder b, String fieldName, Exponentia
      * @throws IOException if the XContentParser throws an IOException
      */
     public static ExponentialHistogram parseForTesting(XContentParser xContent) throws IOException {
+        if (xContent.currentToken() == null) {
+            xContent.nextToken();
+        }
+        if (xContent.currentToken() == XContentParser.Token.VALUE_NULL) {
+            return null;
+        }
         return parseForTesting(xContent.map());
     }
 
@@ -130,7 +141,10 @@ public static ExponentialHistogram parseForTesting(XContentParser xContent) thro
      * @param xContent the serialized histogram as a map
      * @return the deserialized histogram
      */
-    public static ExponentialHistogram parseForTesting(Map<String, Object> xContent) {
+    public static ExponentialHistogram parseForTesting(@Nullable Map<String, Object> xContent) {
+        if (xContent == null) {
+            return null;
+        }
         int scale = ((Number) xContent.get(SCALE_FIELD)).intValue();
         ExponentialHistogramBuilder builder = ExponentialHistogram.builder(scale, ExponentialHistogramCircuitBreaker.noop());
 

libs/exponential-histogram/src/test/java/org/elasticsearch/exponentialhistogram/ExponentialHistogramXContentTests.java

@@ -33,6 +33,11 @@
 
 public class ExponentialHistogramXContentTests extends ExponentialHistogramTestCase {
 
+    public void testNullHistogram() {
+        assertThat(toJson(null), equalTo("null"));
+        checkRoundTrip(null);
+    }
+
     public void testEmptyHistogram() {
         ExponentialHistogram emptyHistogram = ExponentialHistogram.empty();
         assertThat(toJson(emptyHistogram), equalTo("{\"scale\":" + emptyHistogram.scale() + ",\"sum\":0.0}"));

x-pack/plugin/esql/qa/testFixtures/src/main/java/org/elasticsearch/xpack/esql/CsvTestUtils.java

@@ -23,16 +23,21 @@
 import org.elasticsearch.compute.data.ElementType;
 import org.elasticsearch.compute.data.Page;
 import org.elasticsearch.core.Booleans;
+import org.elasticsearch.core.Nullable;
 import org.elasticsearch.core.Releasable;
 import org.elasticsearch.core.Releasables;
 import org.elasticsearch.core.Strings;
 import org.elasticsearch.core.Tuple;
 import org.elasticsearch.exponentialhistogram.ExponentialHistogram;
+import org.elasticsearch.exponentialhistogram.ExponentialHistogramXContent;
 import org.elasticsearch.geometry.utils.Geohash;
 import org.elasticsearch.h3.H3;
 import org.elasticsearch.logging.Logger;
 import org.elasticsearch.search.aggregations.bucket.geogrid.GeoTileUtils;
 import org.elasticsearch.test.VersionUtils;
+import org.elasticsearch.xcontent.XContentParser;
+import org.elasticsearch.xcontent.XContentParserConfiguration;
+import org.elasticsearch.xcontent.json.JsonXContent;
 import org.elasticsearch.xpack.esql.action.ResponseValueUtils;
 import org.elasticsearch.xpack.esql.core.type.DataType;
 import org.elasticsearch.xpack.esql.core.util.StringUtils;
@@ -499,7 +504,7 @@ public enum Type {
             AggregateMetricDoubleBlockBuilder.AggregateMetricDoubleLiteral.class
         ),
         DENSE_VECTOR(Float::parseFloat, Float.class, false),
-        EXPONENTIAL_HISTOGRAM(x -> x == null ? null : JsonBackedExponentialHistogram.createFromJson(x), ExponentialHistogram.class),
+        EXPONENTIAL_HISTOGRAM(CsvTestUtils::parseExponentialHistogram, ExponentialHistogram.class),
         UNSUPPORTED(Type::convertUnsupported, Void.class);
 
         private static Void convertUnsupported(String s) {
@@ -701,4 +706,15 @@ private static double scaledFloat(String value, String factor) {
         double scalingFactor = Double.parseDouble(factor);
         return new BigDecimal(value).multiply(BigDecimal.valueOf(scalingFactor)).longValue() / scalingFactor;
     }
+
+    private static ExponentialHistogram parseExponentialHistogram(@Nullable String json) {
+        if (json == null) {
+            return null;
+        }
+        try (XContentParser parser = JsonXContent.jsonXContent.createParser(XContentParserConfiguration.EMPTY, json)) {
+            return ExponentialHistogramXContent.parseForTesting(parser);
+        } catch (IOException e) {
+            throw new IllegalArgumentException(e);
+        }
+    }
 }

x-pack/plugin/esql/qa/testFixtures/src/main/java/org/elasticsearch/xpack/esql/JsonBackedExponentialHistogram.java

@@ -42,6 +42,7 @@
 import org.elasticsearch.core.Types;
 import org.elasticsearch.exponentialhistogram.ExponentialHistogram;
 import org.elasticsearch.exponentialhistogram.ExponentialHistogramCircuitBreaker;
+import org.elasticsearch.exponentialhistogram.ExponentialHistogramXContent;
 import org.elasticsearch.geo.GeometryTestUtils;
 import org.elasticsearch.geo.ShapeTestUtils;
 import org.elasticsearch.geometry.Point;
@@ -62,7 +63,6 @@
 import org.elasticsearch.xcontent.XContentParser;
 import org.elasticsearch.xcontent.XContentType;
 import org.elasticsearch.xcontent.json.JsonXContent;
-import org.elasticsearch.xpack.esql.JsonBackedExponentialHistogram;
 import org.elasticsearch.xpack.esql.core.type.DataType;
 import org.elasticsearch.xpack.esql.planner.PlannerUtils;
 import org.elasticsearch.xpack.esql.type.UnsupportedEsFieldTests;
@@ -1268,7 +1268,8 @@ static Page valuesToPage(BlockFactory blockFactory, List<ColumnInfoImpl> columns
                     }
                     case EXPONENTIAL_HISTOGRAM -> {
                         ExponentialHistogramBlockBuilder expHistoBuilder = (ExponentialHistogramBlockBuilder) builder;
-                        expHistoBuilder.append(JsonBackedExponentialHistogram.createFromMap(Types.forciblyCast(value)));
+                        Map<String, Object> serializedHisto = Types.forciblyCast(value);
+                        expHistoBuilder.append(ExponentialHistogramXContent.parseForTesting(serializedHisto));
                     }
                 }
             }