DATAES-462 - Add support for mapping max score and document scores.

Original pull request: #207.

Author: xhaggi

src/main/java/org/springframework/data/elasticsearch/annotations/Score.java

@@ -0,0 +1,23 @@
+package org.springframework.data.elasticsearch.annotations;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.springframework.data.annotation.ReadOnlyProperty;
+
+/**
+ * Specifies that this field is used for storing the document score.
+ * 
+ * @author Sascha Woo
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.FIELD)
+@Documented
+@Inherited
+@ReadOnlyProperty
+public @interface Score {
+}

src/main/java/org/springframework/data/elasticsearch/core/DefaultResultMapper.java

@@ -54,6 +54,7 @@
  * @author Chris White
  * @author Mark Paluch
  * @author Ilkang Na
+ * @author Sascha Woo
  */
 public class DefaultResultMapper extends AbstractResultMapper {
 
@@ -82,6 +83,8 @@ public DefaultResultMapper(
 	@Override
 	public <T> AggregatedPage<T> mapResults(SearchResponse response, Class<T> clazz, Pageable pageable) {
 		long totalHits = response.getHits().getTotalHits();
+		float maxScore = response.getHits().getMaxScore();
+
 		List<T> results = new ArrayList<>();
 		for (SearchHit hit : response.getHits()) {
 			if (hit != null) {
@@ -91,14 +94,17 @@ public <T> AggregatedPage<T> mapResults(SearchResponse response, Class<T> clazz,
 				} else {
 					result = mapEntity(hit.getFields().values(), clazz);
 				}
+
 				setPersistentEntityId(result, hit.getId(), clazz);
 				setPersistentEntityVersion(result, hit.getVersion(), clazz);
+				setPersistentEntityScore(result, hit.getScore(), clazz);
 				populateScriptFields(result, hit);
 				results.add(result);
 			}
 		}
 
-        return new AggregatedPageImpl<T>(results, pageable, totalHits, response.getAggregations(), response.getScrollId());
+		return new AggregatedPageImpl<T>(results, pageable, totalHits, response.getAggregations(), response.getScrollId(),
+				maxScore);
 	}
 
 	private <T> void populateScriptFields(T result, SearchHit hit) {
@@ -113,8 +119,8 @@ private <T> void populateScriptFields(T result, SearchHit hit) {
 						try {
 							field.set(result, searchHitField.getValue());
 						} catch (IllegalArgumentException e) {
-							throw new ElasticsearchException("failed to set scripted field: " + name + " with value: "
-									+ searchHitField.getValue(), e);
+							throw new ElasticsearchException(
+									"failed to set scripted field: " + name + " with value: " + searchHitField.getValue(), e);
 						} catch (IllegalAccessException e) {
 							throw new ElasticsearchException("failed to access scripted field: " + name, e);
 						}
@@ -178,23 +184,19 @@ public <T> LinkedList<T> mapResults(MultiGetResponse responses, Class<T> clazz)
 	}
 
 	private <T> void setPersistentEntityId(T result, String id, Class<T> clazz) {
-
 		if (mappingContext != null && clazz.isAnnotationPresent(Document.class)) {
-
 			ElasticsearchPersistentEntity<?> persistentEntity = mappingContext.getRequiredPersistentEntity(clazz);
 			ElasticsearchPersistentProperty idProperty = persistentEntity.getIdProperty();
 
 			// Only deal with String because ES generated Ids are strings !
 			if (idProperty != null && idProperty.getType().isAssignableFrom(String.class)) {
 				persistentEntity.getPropertyAccessor(result).setProperty(idProperty, id);
 			}
-
 		}
 	}
 
 	private <T> void setPersistentEntityVersion(T result, long version, Class<T> clazz) {
 		if (mappingContext != null && clazz.isAnnotationPresent(Document.class)) {
-
 			ElasticsearchPersistentEntity<?> persistentEntity = mappingContext.getPersistentEntity(clazz);
 			ElasticsearchPersistentProperty versionProperty = persistentEntity.getVersionProperty();
 
@@ -207,4 +209,16 @@ private <T> void setPersistentEntityVersion(T result, long version, Class<T> cla
 			}
 		}
 	}
+
+	private <T> void setPersistentEntityScore(T result, float score, Class<T> clazz) {
+		if (mappingContext != null && clazz.isAnnotationPresent(Document.class)) {
+			ElasticsearchPersistentEntity<?> persistentEntity = mappingContext.getRequiredPersistentEntity(clazz);
+			ElasticsearchPersistentProperty scoreProperty = persistentEntity.getScoreProperty();
+			Class<?> type = scoreProperty.getType();
+
+			if (scoreProperty != null && (type == Float.class || type == Float.TYPE)) {
+				persistentEntity.getPropertyAccessor(result).setProperty(scoreProperty, score);
+			}
+		}
+	}
 }

src/main/java/org/springframework/data/elasticsearch/core/ScoredPage.java

@@ -0,0 +1,16 @@
+
+package org.springframework.data.elasticsearch.core;
+
+import org.springframework.data.domain.Page;
+
+/**
+ * A score-aware page gaining information about max score.
+ * 
+ * @param <T>
+ * @author Sascha Woo
+ */
+public interface ScoredPage<T> extends Page<T> {
+
+	float getMaxScore();
+
+}

src/main/java/org/springframework/data/elasticsearch/core/aggregation/AggregatedPage.java

@@ -3,12 +3,14 @@
 import org.elasticsearch.search.aggregations.Aggregation;
 import org.elasticsearch.search.aggregations.Aggregations;
 import org.springframework.data.elasticsearch.core.FacetedPage;
+import org.springframework.data.elasticsearch.core.ScoredPage;
 import org.springframework.data.elasticsearch.core.ScrolledPage;
 
 /**
  * @author Petar Tahchiev
+ * @author Sascha Woo
  */
-public interface AggregatedPage<T> extends FacetedPage<T>, ScrolledPage<T> {
+public interface AggregatedPage<T> extends FacetedPage<T>, ScrolledPage<T>, ScoredPage<T> {
 
 	boolean hasAggregations();
 

src/main/java/org/springframework/data/elasticsearch/core/aggregation/impl/AggregatedPageImpl.java

@@ -15,9 +15,7 @@
  */
 package org.springframework.data.elasticsearch.core.aggregation.impl;
 
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
 
 import org.elasticsearch.search.aggregations.Aggregation;
 import org.elasticsearch.search.aggregations.Aggregations;
@@ -29,55 +27,77 @@
  * @author Petar Tahchiev
  * @author Artur Konczak
  * @author Mohsin Husen
+ * @author Sascha Woo
  */
 public class AggregatedPageImpl<T> extends FacetedPageImpl<T> implements AggregatedPage<T> {
 
 	private Aggregations aggregations;
-	private Map<String, Aggregation> mapOfAggregations = new HashMap<>();
-    private String scrollId;
+	private String scrollId;
+	private float maxScore;
 
 	public AggregatedPageImpl(List<T> content) {
 		super(content);
 	}
 
+	public AggregatedPageImpl(List<T> content, float maxScore) {
+		super(content);
+		this.maxScore = maxScore;
+	}
+
 	public AggregatedPageImpl(List<T> content, String scrollId) {
 		super(content);
 		this.scrollId = scrollId;
 	}
 
+	public AggregatedPageImpl(List<T> content, String scrollId, float maxScore) {
+		this(content, scrollId);
+		this.maxScore = maxScore;
+	}
+
 	public AggregatedPageImpl(List<T> content, Pageable pageable, long total) {
 		super(content, pageable, total);
 	}
 
+	public AggregatedPageImpl(List<T> content, Pageable pageable, long total, float maxScore) {
+		super(content, pageable, total);
+		this.maxScore = maxScore;
+	}
+
 	public AggregatedPageImpl(List<T> content, Pageable pageable, long total, String scrollId) {
 		super(content, pageable, total);
 		this.scrollId = scrollId;
 	}
 
+	public AggregatedPageImpl(List<T> content, Pageable pageable, long total, String scrollId, float maxScore) {
+		this(content, pageable, total, scrollId);
+		this.maxScore = maxScore;
+	}
+
 	public AggregatedPageImpl(List<T> content, Pageable pageable, long total, Aggregations aggregations) {
 		super(content, pageable, total);
 		this.aggregations = aggregations;
-		if (aggregations != null) {
-			for (Aggregation aggregation : aggregations) {
-				mapOfAggregations.put(aggregation.getName(), aggregation);
-			}
-		}
 	}
 
-	public AggregatedPageImpl(List<T> content, Pageable pageable, long total, Aggregations aggregations, String scrollId) {
-		super(content, pageable, total);
-		this.aggregations = aggregations;
+	public AggregatedPageImpl(List<T> content, Pageable pageable, long total, Aggregations aggregations, float maxScore) {
+		this(content, pageable, total, aggregations);
+		this.maxScore = maxScore;
+	}
+
+	public AggregatedPageImpl(List<T> content, Pageable pageable, long total, Aggregations aggregations,
+			String scrollId) {
+		this(content, pageable, total, aggregations);
 		this.scrollId = scrollId;
-		if (aggregations != null) {
-			for (Aggregation aggregation : aggregations) {
-				mapOfAggregations.put(aggregation.getName(), aggregation);
-			}
-		}
+	}
+
+	public AggregatedPageImpl(List<T> content, Pageable pageable, long total, Aggregations aggregations, String scrollId,
+			float maxScore) {
+		this(content, pageable, total, aggregations, scrollId);
+		this.maxScore = maxScore;
 	}
 
 	@Override
 	public boolean hasAggregations() {
-		return aggregations != null && mapOfAggregations.size() > 0;
+		return aggregations != null;
 	}
 
 	@Override
@@ -94,4 +114,9 @@ public Aggregation getAggregation(String name) {
 	public String getScrollId() {
 		return scrollId;
 	}
+
+	@Override
+	public float getMaxScore() {
+		return maxScore;
+	}
 }

src/main/java/org/springframework/data/elasticsearch/core/mapping/ElasticsearchPersistentEntity.java

@@ -16,13 +16,15 @@
 package org.springframework.data.elasticsearch.core.mapping;
 
 import org.springframework.data.mapping.PersistentEntity;
+import org.springframework.lang.Nullable;
 
 /**
  * ElasticsearchPersistentEntity
  *
  * @author Rizwan Idrees
  * @author Mohsin Husen
  * @author Mark Paluch
+ * @author Sascha Woo
  */
 public interface ElasticsearchPersistentEntity<T> extends PersistentEntity<T, ElasticsearchPersistentProperty> {
 
@@ -49,4 +51,22 @@ public interface ElasticsearchPersistentEntity<T> extends PersistentEntity<T, El
 	String settingPath();
 
 	boolean isCreateIndexAndMapping();
+
+	/**
+	 * Returns whether the {@link ElasticsearchPersistentEntity} has an score property. If this call returns
+	 * {@literal true}, {@link #getScoreProperty()} will return a non-{@literal null} value.
+	 *
+	 * @return false when {@link ElasticsearchPersistentEntity} does not define a score property.
+	 */
+	boolean hasScoreProperty();
+
+	/**
+	 * Returns the score property of the {@link ElasticsearchPersistentEntity}. Can be {@literal null} in case no score
+	 * property is available on the entity.
+	 *
+	 * @return the score {@link ElasticsearchPersistentProperty} of the {@link PersistentEntity} or {@literal null} if not
+	 *         defined.
+	 */
+	@Nullable
+	ElasticsearchPersistentProperty getScoreProperty();
 }

src/main/java/org/springframework/data/elasticsearch/core/mapping/ElasticsearchPersistentProperty.java

@@ -23,12 +23,24 @@
  *
  * @author Rizwan Idrees
  * @author Mohsin Husen
+ * @author Sascha Woo
  */
 
 public interface ElasticsearchPersistentProperty extends PersistentProperty<ElasticsearchPersistentProperty> {
 
 	String getFieldName();
 
+	/**
+	 * Returns whether the current property is a <em>potential</em> score property of the owning
+	 * {@link ElasticsearchPersistentEntity}. This method is mainly used by {@link ElasticsearchPersistentEntity}
+	 * implementation to discover score property candidates on {@link ElasticsearchPersistentEntity} creation you should
+	 * rather call {@link ElasticsearchPersistentEntity#isScoreProperty(PersistentProperty)} to determine whether the
+	 * current property is the version property of that {@link ElasticsearchPersistentEntity} under consideration.
+	 *
+	 * @return
+	 */
+	boolean isScoreProperty();
+
 	public enum PropertyToFieldNameConverter implements Converter<ElasticsearchPersistentProperty, String> {
 
 		INSTANCE;