HSEARCH-5133 Support basic metrics aggregations

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/aggregation/impl/ElasticsearchMetricFieldAggregation.java

@@ -0,0 +1,201 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.search.backend.elasticsearch.search.aggregation.impl;
+
+import java.util.List;
+import java.util.Optional;
+
+import org.hibernate.search.backend.elasticsearch.gson.impl.JsonAccessor;
+import org.hibernate.search.backend.elasticsearch.search.common.impl.AbstractElasticsearchCodecAwareSearchQueryElementFactory;
+import org.hibernate.search.backend.elasticsearch.search.common.impl.ElasticsearchSearchIndexScope;
+import org.hibernate.search.backend.elasticsearch.search.common.impl.ElasticsearchSearchIndexValueFieldContext;
+import org.hibernate.search.backend.elasticsearch.search.predicate.impl.ElasticsearchSearchPredicate;
+import org.hibernate.search.backend.elasticsearch.types.codec.impl.ElasticsearchFieldCodec;
+import org.hibernate.search.engine.backend.types.converter.runtime.FromDocumentValueConvertContext;
+import org.hibernate.search.engine.backend.types.converter.spi.ProjectionConverter;
+import org.hibernate.search.engine.search.aggregation.spi.FieldMetricAggregationBuilder;
+import org.hibernate.search.engine.search.common.ValueModel;
+import org.hibernate.search.util.common.AssertionFailure;
+
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+
+/**
+ * @param <F> The type of field values.
+ * @param <K> The type of returned value. It can be {@code F}, {@link Double}
+ * or a different type if value converters are used.
+ */
+public class ElasticsearchMetricFieldAggregation<F, K> extends AbstractElasticsearchNestableAggregation<K> {
+
+	private static final JsonAccessor<JsonObject> SUM_PROPERTY_ACCESSOR =
+			JsonAccessor.root().property( "sum" ).asObject();
+
+	private static final JsonAccessor<JsonObject> MIN_PROPERTY_ACCESSOR =
+			JsonAccessor.root().property( "min" ).asObject();
+
+	private static final JsonAccessor<JsonObject> MAX_PROPERTY_ACCESSOR =
+			JsonAccessor.root().property( "max" ).asObject();
+
+	private static final JsonAccessor<JsonObject> AVG_PROPERTY_ACCESSOR =
+			JsonAccessor.root().property( "avg" ).asObject();
+
+	private static final JsonAccessor<String> FIELD_PROPERTY_ACCESSOR =
+			JsonAccessor.root().property( "field" ).asString();
+
+	private static final JsonAccessor<Double> VALUE_ACCESSOR =
+			JsonAccessor.root().property( "value" ).asDouble();
+
+	public static <F> ElasticsearchMetricFieldAggregation.Factory<F> sum(ElasticsearchFieldCodec<F> codec) {
+		return new ElasticsearchMetricFieldAggregation.Factory<>( codec, SUM_PROPERTY_ACCESSOR );
+	}
+
+	public static <F> ElasticsearchMetricFieldAggregation.Factory<F> min(ElasticsearchFieldCodec<F> codec) {
+		return new ElasticsearchMetricFieldAggregation.Factory<>( codec, MIN_PROPERTY_ACCESSOR );
+	}
+
+	public static <F> ElasticsearchMetricFieldAggregation.Factory<F> max(ElasticsearchFieldCodec<F> codec) {
+		return new ElasticsearchMetricFieldAggregation.Factory<>( codec, MAX_PROPERTY_ACCESSOR );
+	}
+
+	public static <F> ElasticsearchMetricFieldAggregation.Factory<F> avg(ElasticsearchFieldCodec<F> codec) {
+		return new ElasticsearchMetricFieldAggregation.Factory<>( codec, AVG_PROPERTY_ACCESSOR );
+	}
+
+	private final String absoluteFieldPath;
+	private final ProjectionConverter<F, ? extends K> fromFieldValueConverter;
+	private final ElasticsearchFieldCodec<F> codec;
+	private final JsonAccessor<JsonObject> operation;
+
+	private ElasticsearchMetricFieldAggregation(Builder<F, K> builder) {
+		super( builder );
+		this.absoluteFieldPath = builder.field.absolutePath();
+		this.fromFieldValueConverter = builder.fromFieldValueConverter;
+		this.codec = builder.codec;
+		this.operation = builder.operation;
+	}
+
+	@Override
+	protected final JsonObject doRequest(AggregationRequestContext context) {
+		JsonObject outerObject = new JsonObject();
+		JsonObject innerObject = new JsonObject();
+
+		operation.set( outerObject, innerObject );
+		FIELD_PROPERTY_ACCESSOR.set( innerObject, absoluteFieldPath );
+		return outerObject;
+	}
+
+	@Override
+	protected Extractor<K> extractor(AggregationRequestContext context) {
+		return new MetricFieldExtractor( nestedPathHierarchy, filter );
+	}
+
+	private static class Factory<F>
+			extends
+			AbstractElasticsearchCodecAwareSearchQueryElementFactory<FieldMetricAggregationBuilder.TypeSelector, F> {
+
+		private final JsonAccessor<JsonObject> operation;
+
+		private Factory(ElasticsearchFieldCodec<F> codec, JsonAccessor<JsonObject> operation) {
+			super( codec );
+			this.operation = operation;
+		}
+
+		@Override
+		public FieldMetricAggregationBuilder.TypeSelector create(ElasticsearchSearchIndexScope<?> scope,
+				ElasticsearchSearchIndexValueFieldContext<F> field) {
+			return new ElasticsearchMetricFieldAggregation.TypeSelector<>( codec, scope, field, operation );
+		}
+	}
+
+	private static class TypeSelector<F> implements FieldMetricAggregationBuilder.TypeSelector {
+		private final ElasticsearchFieldCodec<F> codec;
+		private final ElasticsearchSearchIndexScope<?> scope;
+		private final ElasticsearchSearchIndexValueFieldContext<F> field;
+		private final JsonAccessor<JsonObject> operation;
+
+		private TypeSelector(ElasticsearchFieldCodec<F> codec,
+				ElasticsearchSearchIndexScope<?> scope, ElasticsearchSearchIndexValueFieldContext<F> field,
+				JsonAccessor<JsonObject> operation) {
+			this.codec = codec;
+			this.scope = scope;
+			this.field = field;
+			this.operation = operation;
+		}
+
+		@Override
+		public <T> Builder<F, T> type(Class<T> expectedType, ValueModel valueModel) {
+			ProjectionConverter<F, ? extends T> projectionConverter = null;
+			if ( useProjectionConverter( expectedType, valueModel ) ) {
+				projectionConverter = field.type().projectionConverter( valueModel )
+						.withConvertedType( expectedType, field );
+			}
+			return new Builder<>( codec, scope, field,
+					projectionConverter,
+					operation
+			);
+		}
+
+		private <T> boolean useProjectionConverter(Class<T> expectedType, ValueModel valueModel) {
+			if ( !Double.class.isAssignableFrom( expectedType ) ) {
+				if ( ValueModel.RAW.equals( valueModel ) ) {
+					throw new AssertionFailure(
+							"Raw projection converter is not supported with metric aggregations at the moment" );
+				}
+				return true;
+			}
+
+			// expectedType == Double.class
+			if ( ValueModel.RAW.equals( valueModel ) ) {
+				return false;
+			}
+			return field.type().projectionConverter( valueModel ).valueType().isAssignableFrom( Double.class );
+		}
+	}
+
+	private class MetricFieldExtractor extends AbstractExtractor<K> {
+		protected MetricFieldExtractor(List<String> nestedPathHierarchy, ElasticsearchSearchPredicate filter) {
+			super( nestedPathHierarchy, filter );
+		}
+
+		@Override
+		@SuppressWarnings("unchecked")
+		protected K doExtract(JsonObject aggregationResult, AggregationExtractContext context) {
+			FromDocumentValueConvertContext convertContext = context.fromDocumentValueConvertContext();
+			Optional<Double> value = VALUE_ACCESSOR.get( aggregationResult );
+			JsonElement valueAsString = aggregationResult.get( "value_as_string" );
+
+			if ( fromFieldValueConverter == null ) {
+				Double decode = value.orElse( null );
+				return (K) decode;
+			}
+			return fromFieldValueConverter.fromDocumentValue(
+					codec.decodeAggregationValue( value, valueAsString ),
+					convertContext
+			);
+		}
+	}
+
+	private static class Builder<F, K> extends AbstractBuilder<K>
+			implements FieldMetricAggregationBuilder<K> {
+
+		private final ElasticsearchFieldCodec<F> codec;
+		private final ProjectionConverter<F, ? extends K> fromFieldValueConverter;
+		private final JsonAccessor<JsonObject> operation;
+
+		private Builder(ElasticsearchFieldCodec<F> codec, ElasticsearchSearchIndexScope<?> scope,
+				ElasticsearchSearchIndexValueFieldContext<F> field,
+				ProjectionConverter<F, ? extends K> fromFieldValueConverter, JsonAccessor<JsonObject> operation) {
+			super( scope, field );
+			this.codec = codec;
+			this.fromFieldValueConverter = fromFieldValueConverter;
+			this.operation = operation;
+		}
+
+		@Override
+		public ElasticsearchMetricFieldAggregation<F, K> build() {
+			return new ElasticsearchMetricFieldAggregation<>( this );
+		}
+	}
+}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/aggregation/impl/ElasticsearchMetricLongAggregation.java

@@ -0,0 +1,108 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.search.backend.elasticsearch.search.aggregation.impl;
+
+import java.util.List;
+
+import org.hibernate.search.backend.elasticsearch.gson.impl.JsonAccessor;
+import org.hibernate.search.backend.elasticsearch.gson.impl.JsonElementTypes;
+import org.hibernate.search.backend.elasticsearch.search.common.impl.AbstractElasticsearchCodecAwareSearchQueryElementFactory;
+import org.hibernate.search.backend.elasticsearch.search.common.impl.ElasticsearchSearchIndexScope;
+import org.hibernate.search.backend.elasticsearch.search.common.impl.ElasticsearchSearchIndexValueFieldContext;
+import org.hibernate.search.backend.elasticsearch.search.predicate.impl.ElasticsearchSearchPredicate;
+import org.hibernate.search.backend.elasticsearch.types.codec.impl.ElasticsearchFieldCodec;
+import org.hibernate.search.engine.search.aggregation.spi.SearchFilterableAggregationBuilder;
+
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+
+public class ElasticsearchMetricLongAggregation extends AbstractElasticsearchNestableAggregation<Long> {
+
+	private static final JsonAccessor<JsonObject> COUNT_PROPERTY_ACCESSOR =
+			JsonAccessor.root().property( "value_count" ).asObject();
+
+	private static final JsonAccessor<JsonObject> COUNT_DISTINCT_PROPERTY_ACCESSOR =
+			JsonAccessor.root().property( "cardinality" ).asObject();
+
+	private static final JsonAccessor<String> FIELD_PROPERTY_ACCESSOR =
+			JsonAccessor.root().property( "field" ).asString();
+
+	public static <F> ElasticsearchMetricLongAggregation.Factory<F> count(ElasticsearchFieldCodec<F> codec) {
+		return new ElasticsearchMetricLongAggregation.Factory<>( codec, COUNT_PROPERTY_ACCESSOR );
+	}
+
+	public static <F> ElasticsearchMetricLongAggregation.Factory<F> countDistinct(ElasticsearchFieldCodec<F> codec) {
+		return new ElasticsearchMetricLongAggregation.Factory<>( codec, COUNT_DISTINCT_PROPERTY_ACCESSOR );
+	}
+
+	private final String absoluteFieldPath;
+	private final JsonAccessor<JsonObject> operation;
+
+	private ElasticsearchMetricLongAggregation(Builder builder) {
+		super( builder );
+		this.absoluteFieldPath = builder.field.absolutePath();
+		this.operation = builder.operation;
+	}
+
+	@Override
+	protected final JsonObject doRequest(AggregationRequestContext context) {
+		JsonObject outerObject = new JsonObject();
+		JsonObject innerObject = new JsonObject();
+
+		operation.set( outerObject, innerObject );
+		FIELD_PROPERTY_ACCESSOR.set( innerObject, absoluteFieldPath );
+		return outerObject;
+	}
+
+	@Override
+	protected Extractor<Long> extractor(AggregationRequestContext context) {
+		return new MetricLongExtractor( nestedPathHierarchy, filter );
+	}
+
+	private static class Factory<F>
+			extends
+			AbstractElasticsearchCodecAwareSearchQueryElementFactory<SearchFilterableAggregationBuilder<Long>, F> {
+
+		private final JsonAccessor<JsonObject> operation;
+
+		private Factory(ElasticsearchFieldCodec<F> codec, JsonAccessor<JsonObject> operation) {
+			super( codec );
+			this.operation = operation;
+		}
+
+		@Override
+		public SearchFilterableAggregationBuilder<Long> create(ElasticsearchSearchIndexScope<?> scope,
+				ElasticsearchSearchIndexValueFieldContext<F> field) {
+			return new Builder( scope, field, operation );
+		}
+	}
+
+	private static class MetricLongExtractor extends AbstractExtractor<Long> {
+		protected MetricLongExtractor(List<String> nestedPathHierarchy, ElasticsearchSearchPredicate filter) {
+			super( nestedPathHierarchy, filter );
+		}
+
+		@Override
+		protected Long doExtract(JsonObject aggregationResult, AggregationExtractContext context) {
+			JsonElement value = aggregationResult.get( "value" );
+			return JsonElementTypes.LONG.fromElement( value );
+		}
+	}
+
+	private static class Builder extends AbstractBuilder<Long> implements SearchFilterableAggregationBuilder<Long> {
+		private final JsonAccessor<JsonObject> operation;
+
+		private Builder(ElasticsearchSearchIndexScope<?> scope, ElasticsearchSearchIndexValueFieldContext<?> field,
+				JsonAccessor<JsonObject> operation) {
+			super( scope, field );
+			this.operation = operation;
+		}
+
+		@Override
+		public ElasticsearchMetricLongAggregation build() {
+			return new ElasticsearchMetricLongAggregation( this );
+		}
+	}
+}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/types/codec/impl/ElasticsearchBigDecimalFieldCodec.java

@@ -12,6 +12,7 @@
 import org.hibernate.search.backend.elasticsearch.gson.impl.JsonElementTypes;
 import org.hibernate.search.backend.elasticsearch.logging.impl.Log;
 import org.hibernate.search.engine.cfg.spi.NumberScaleConstants;
+import org.hibernate.search.engine.cfg.spi.NumberUtils;
 import org.hibernate.search.util.common.logging.impl.LoggerFactory;
 
 import com.google.gson.Gson;
@@ -65,6 +66,11 @@ public BigDecimal decode(JsonElement element) {
 		return JsonElementTypes.BIG_DECIMAL.fromElement( element );
 	}
 
+	@Override
+	public BigDecimal decode(Double value) {
+		return NumberUtils.toBigDecimal( value ).setScale( decimalScale, RoundingMode.FLOOR );
+	}
+
 	@Override
 	public boolean isCompatibleWith(ElasticsearchFieldCodec<?> obj) {
 		if ( this == obj ) {

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/types/codec/impl/ElasticsearchBigIntegerFieldCodec.java

@@ -13,6 +13,7 @@
 import org.hibernate.search.backend.elasticsearch.gson.impl.JsonElementTypes;
 import org.hibernate.search.backend.elasticsearch.logging.impl.Log;
 import org.hibernate.search.engine.cfg.spi.NumberScaleConstants;
+import org.hibernate.search.engine.cfg.spi.NumberUtils;
 import org.hibernate.search.util.common.logging.impl.LoggerFactory;
 
 import com.google.gson.Gson;
@@ -67,6 +68,11 @@ public BigInteger decode(JsonElement element) {
 		return JsonElementTypes.BIG_INTEGER.fromElement( element );
 	}
 
+	@Override
+	public BigInteger decode(Double value) {
+		return NumberUtils.toBigInteger( value );
+	}
+
 	@Override
 	public BigInteger decodeAggregationKey(JsonElement key, JsonElement keyAsString) {
 		if ( key == null || key.isJsonNull() ) {

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/types/codec/impl/ElasticsearchBooleanFieldCodec.java

@@ -33,6 +33,11 @@ public Boolean decode(JsonElement element) {
 		return JsonElementTypes.BOOLEAN.fromElement( element );
 	}
 
+	@Override
+	public Boolean decode(Double value) {
+		return value != 0;
+	}
+
 	@Override
 	public Boolean decodeAggregationKey(JsonElement key, JsonElement keyAsString) {
 		if ( key == null || key.isJsonNull() ) {

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/types/codec/impl/ElasticsearchByteFieldCodec.java

@@ -5,6 +5,7 @@
 package org.hibernate.search.backend.elasticsearch.types.codec.impl;
 
 import org.hibernate.search.backend.elasticsearch.gson.impl.JsonElementTypes;
+import org.hibernate.search.engine.cfg.spi.NumberUtils;
 
 import com.google.gson.Gson;
 import com.google.gson.JsonElement;
@@ -33,6 +34,11 @@ public Byte decode(JsonElement element) {
 		return JsonElementTypes.BYTE.fromElement( element );
 	}
 
+	@Override
+	public Byte decode(Double value) {
+		return NumberUtils.toByte( value );
+	}
+
 	@Override
 	public boolean isCompatibleWith(ElasticsearchFieldCodec<?> other) {
 		return other instanceof ElasticsearchByteFieldCodec;

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/types/codec/impl/ElasticsearchDoubleFieldCodec.java

@@ -33,6 +33,11 @@ public Double decode(JsonElement element) {
 		return JsonElementTypes.DOUBLE.fromElement( element );
 	}
 
+	@Override
+	public Double decode(Double value) {
+		return value;
+	}
+
 	@Override
 	public boolean isCompatibleWith(ElasticsearchFieldCodec<?> other) {
 		return other instanceof ElasticsearchDoubleFieldCodec;