From fe2fa3715a92e096f3f1e09536d077e65aa47f77 Mon Sep 17 00:00:00 2001
From: Fabio Massimo Ercoli <fabiomassimo.ercoli@gmail.com>
Date: Fri, 5 Feb 2021 17:44:43 +0100
Subject: [PATCH] HSEARCH-3863 Add missing option to DistanceSortOptionsStep

---
 .../DistanceSortMissingValueBehaviorStep.java | 48 +++++++++++++++++++
 .../sort/dsl/DistanceSortOptionsStep.java     |  8 ++++
 .../dsl/impl/DistanceSortOptionsStepImpl.java | 28 ++++++++++-
 3 files changed, 83 insertions(+), 1 deletion(-)
 create mode 100644 engine/src/main/java/org/hibernate/search/engine/search/sort/dsl/DistanceSortMissingValueBehaviorStep.java

diff --git a/engine/src/main/java/org/hibernate/search/engine/search/sort/dsl/DistanceSortMissingValueBehaviorStep.java b/engine/src/main/java/org/hibernate/search/engine/search/sort/dsl/DistanceSortMissingValueBehaviorStep.java
new file mode 100644
index 00000000000..73e7f2ed750
--- /dev/null
+++ b/engine/src/main/java/org/hibernate/search/engine/search/sort/dsl/DistanceSortMissingValueBehaviorStep.java
@@ -0,0 +1,48 @@
+/*
+ * Hibernate Search, full-text search for your domain model
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.search.engine.search.sort.dsl;
+
+import org.hibernate.search.engine.spatial.GeoPoint;
+
+/**
+ * The step in a sort definition where the behavior on missing values can be set.
+ *
+ * @param <N> The type of the next step (returned by {@link DistanceSortMissingValueBehaviorStep#first()}, for example).
+ *
+ * @author Emmanuel Bernard emmanuel@hibernate.org
+ */
+public interface DistanceSortMissingValueBehaviorStep<N> {
+
+	/**
+	 * Put documents with missing values last in the sorting.
+	 *
+	 * <p>This instruction is independent of whether the sort is being ascending
+	 * or descending.
+	 *
+	 * @return The next step.
+	 */
+	N last();
+
+	/**
+	 * Put documents with missing values first in the sorting.
+	 *
+	 * <p>This instruction is independent of whether the sort is being ascending
+	 * or descending.
+	 *
+	 * @return The next step.
+	 */
+	N first();
+
+	/**
+	 * When documents are missing a value on the sort field, use the given value instead.
+	 *
+	 * @param value The value to use as a default when a document is missing a value on the sort field.
+	 * @return The next step.
+	 */
+	N use(GeoPoint value);
+
+}
diff --git a/engine/src/main/java/org/hibernate/search/engine/search/sort/dsl/DistanceSortOptionsStep.java b/engine/src/main/java/org/hibernate/search/engine/search/sort/dsl/DistanceSortOptionsStep.java
index 202cdb3b107..3373ae5b549 100644
--- a/engine/src/main/java/org/hibernate/search/engine/search/sort/dsl/DistanceSortOptionsStep.java
+++ b/engine/src/main/java/org/hibernate/search/engine/search/sort/dsl/DistanceSortOptionsStep.java
@@ -19,4 +19,12 @@
 public interface DistanceSortOptionsStep<S extends DistanceSortOptionsStep<?, PDF>, PDF extends SearchPredicateFactory>
 		extends SortFinalStep, SortThenStep, SortOrderStep<S>, SortModeStep<S>, SortFilterStep<S, PDF> {
 
+	/**
+	 * Start describing the behavior of this sort when a document doesn't
+	 * have any value for the targeted field.
+	 *
+	 * @return The next step.
+	 */
+	DistanceSortMissingValueBehaviorStep<S> missing();
+
 }
diff --git a/engine/src/main/java/org/hibernate/search/engine/search/sort/dsl/impl/DistanceSortOptionsStepImpl.java b/engine/src/main/java/org/hibernate/search/engine/search/sort/dsl/impl/DistanceSortOptionsStepImpl.java
index a32c5134355..a7ece3ba9d4 100644
--- a/engine/src/main/java/org/hibernate/search/engine/search/sort/dsl/impl/DistanceSortOptionsStepImpl.java
+++ b/engine/src/main/java/org/hibernate/search/engine/search/sort/dsl/impl/DistanceSortOptionsStepImpl.java
@@ -13,6 +13,7 @@
 import org.hibernate.search.engine.search.predicate.dsl.PredicateFinalStep;
 import org.hibernate.search.engine.search.predicate.dsl.SearchPredicateFactory;
 import org.hibernate.search.engine.search.sort.SearchSort;
+import org.hibernate.search.engine.search.sort.dsl.DistanceSortMissingValueBehaviorStep;
 import org.hibernate.search.engine.search.sort.dsl.DistanceSortOptionsStep;
 import org.hibernate.search.engine.search.sort.dsl.SortOrder;
 import org.hibernate.search.engine.search.sort.dsl.spi.AbstractSortThenStep;
@@ -22,7 +23,8 @@
 
 public class DistanceSortOptionsStepImpl<PDF extends SearchPredicateFactory>
 		extends AbstractSortThenStep
-		implements DistanceSortOptionsStep<DistanceSortOptionsStepImpl<PDF>, PDF> {
+		implements DistanceSortOptionsStep<DistanceSortOptionsStepImpl<PDF>, PDF>,
+		DistanceSortMissingValueBehaviorStep<DistanceSortOptionsStepImpl<PDF>> {
 
 	private final DistanceSortBuilder builder;
 	private final SearchSortDslContext<?, ? extends PDF> dslContext;
@@ -61,6 +63,30 @@ public DistanceSortOptionsStepImpl<PDF> filter(SearchPredicate searchPredicate)
 		return this;
 	}
 
+
+	@Override
+	public DistanceSortMissingValueBehaviorStep<DistanceSortOptionsStepImpl<PDF>> missing() {
+		return this;
+	}
+
+	@Override
+	public DistanceSortOptionsStepImpl<PDF> first() {
+		// TODO HSEARCH-3863 builder.missingFirst();
+		return this;
+	}
+
+	@Override
+	public DistanceSortOptionsStepImpl<PDF> last() {
+		// TODO HSEARCH-3863 builder.missingLast();
+		return this;
+	}
+
+	@Override
+	public DistanceSortOptionsStepImpl<PDF> use(GeoPoint value) {
+		// TODO HSEARCH-3863 builder.missingAs( value );
+		return this;
+	}
+
 	@Override
 	protected SearchSort build() {
 		return builder.build();