Implement equals and hashCode for Criteria.

This facilitates testing of Criteria construction and is also usful, when keeping Criteria instances in sets or similar.

Closes #1960

spring-data-relational/src/main/java/org/springframework/data/relational/core/query/Criteria.java

@@ -21,6 +21,7 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.StringJoiner;
 
 import org.springframework.dao.InvalidDataAccessApiUsageException;
@@ -390,6 +391,28 @@ public class Criteria implements CriteriaDefinition {
 		return builder.toString();
 	}
 
+	@Override
+	public boolean equals(Object o) {
+
+		if (o == null || getClass() != o.getClass()) {
+			return false;
+		}
+
+		Criteria criteria = (Criteria) o;
+		return ignoreCase == criteria.ignoreCase //
+				&& Objects.equals(previous, criteria.previous) //
+				&& combinator == criteria.combinator //
+				&& Objects.equals(group, criteria.group) //
+				&& Objects.equals(column, criteria.column) //
+				&& comparator == criteria.comparator //
+				&& Objects.equals(value, criteria.value);
+	}
+
+	@Override
+	public int hashCode() {
+		return Objects.hash(previous, combinator, group, column, comparator, value, ignoreCase);
+	}
+
 	private void unroll(CriteriaDefinition criteria, StringBuilder stringBuilder) {
 
 		CriteriaDefinition current = criteria;

spring-data-relational/src/test/java/org/springframework/data/relational/core/query/CriteriaUnitTests.java

@@ -22,7 +22,6 @@ import static org.springframework.data.relational.core.query.Criteria.*;
 import java.util.Arrays;
 
 import org.junit.jupiter.api.Test;
-
 import org.springframework.data.relational.core.sql.SqlIdentifier;
 
 /**
@@ -297,4 +296,31 @@ class CriteriaUnitTests {
 		assertThat(criteria.getComparator()).isEqualTo(CriteriaDefinition.Comparator.IS_FALSE);
 		assertThat(criteria.getValue()).isEqualTo(false);
 	}
+
+	@Test // GH-1960
+	void identicallyCreatedCriteriaAreEqual() {
+
+		Criteria c1 = Criteria.where("status").in("PUBLISHED", "DRAFT");
+		Criteria c2 = Criteria.where("status").in("PUBLISHED", "DRAFT");
+
+		assertThat(c1).isEqualTo(c2);
+		assertThat(c1.hashCode()).isEqualTo(c2.hashCode());
+	}
+
+	@Test // GH-1960
+	void notIdenticallyCreatedCriteriaAreNotEqual() {
+
+		Criteria[] criteria = new Criteria[] { Criteria.where("status").is("PUBLISHED"), //
+				Criteria.where("statusx").is("PUBLISHED"), //
+				Criteria.where("status").greaterThan("PUBLISHED"), //
+				Criteria.where("status").is("PUBLISHEDx") };
+
+		for (int i = 0; i < criteria.length - 1; i++) {
+			for (int j = i + 1; j < criteria.length; j++) {
+
+				assertThat(criteria[i]).isNotEqualTo(criteria[j]);
+				assertThat(criteria[i].hashCode()).isNotEqualTo(criteria[j].hashCode());
+			}
+		}
+	}
 }