Add Criteria.eq(...).

The Criteria API now offers a dedicated eq method abstracting MongoDB $eq query operator. This allows users to create $not $eq operations instead of having to defer to the ne method.

See: #4606

Author: christophstrobl

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

@@ -200,15 +200,15 @@ public Criteria and(String key) {
 	@Contract("_ -> this")
 	public Criteria is(@Nullable Object value) {
 
+		if (lastOperatorWasNot()) {
+			return eq(value);
+		}
+
 		if (!NOT_SET.equals(isValue)) {
 			throw new InvalidMongoDbApiUsageException(
 					"Multiple 'is' values declared; You need to use 'and' with multiple criteria");
 		}
 
-		if (lastOperatorWasNot()) {
-			throw new InvalidMongoDbApiUsageException("Invalid query: 'not' can't be used with 'is' - use 'ne' instead");
-		}
-
 		this.isValue = value;
 		return this;
 	}
@@ -253,6 +253,21 @@ private boolean lastOperatorWasNot() {
 		return !this.criteria.isEmpty() && "$not".equals(this.criteria.keySet().toArray()[this.criteria.size() - 1]);
 	}
 
+	/**
+	 * Creates a criterion using the {@literal $eq} operator.
+	 *
+	 * @param value can be {@literal null}.
+	 * @return this.
+	 * @see <a href="https://docs.mongodb.com/manual/reference/operator/query/eq/">MongoDB Query operator: $eq</a>
+	 * @since 5.0.4
+	 */
+	@Contract("_ -> this")
+	public Criteria eq(Object value) {
+
+		criteria.put("$eq", value);
+		return this;
+	}
+
 	/**
 	 * Creates a criterion using the {@literal $ne} operator.
 	 *

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

@@ -53,6 +53,13 @@ void testSimpleCriteria() {
 		assertThat(c.getCriteriaObject()).isEqualTo("{ \"name\" : \"Bubba\"}");
 	}
 
+	@Test // GH-4606
+	void testEqualsCriteria() {
+
+		Criteria c = new Criteria("name").eq("Bubba");
+		assertThat(c.getCriteriaObject()).isEqualTo("{ \"name\" : { \"$eq\" :  \"Bubba\"} }");
+	}
+
 	@Test // GH-4850
 	void testCombiningSimpleCriteria() {
 
@@ -70,6 +77,34 @@ void testCombiningSimpleCriteria() {
 		assertThat(c.getCriteriaObject()).isEqualTo(expected);
 	}
 
+	@Test // GH-4606
+	void testCombiningSimpleAndNegatedEqCriteria() {
+
+		Document expected = Document.parse("{ name : { $eq : 123, $type : ['long'], $not : { $eq : 'foo' } } }");
+
+		Criteria c = Criteria.where("name") //
+			.is(123) //
+			.type(Type.INT_64)
+			.not()
+			.eq("foo");
+
+		assertThat(c.getCriteriaObject()).isEqualTo(expected);
+	}
+
+	@Test // GH-4606
+	void testCombiningSimpleAndNegatedIsCriteria() {
+
+		Document expected = Document.parse("{ name : { $eq : 123, $type : ['long'], $not : { $eq : 'foo' } } }");
+
+		Criteria c = Criteria.where("name") //
+			.is(123) //
+			.type(Type.INT_64)
+			.not()
+			.is("foo");
+
+		assertThat(c.getCriteriaObject()).isEqualTo(expected);
+	}
+
 	@Test // GH-4850
 	void testCombiningBsonRegexCriteria() {
 
@@ -94,6 +129,20 @@ void testNotEqualCriteria() {
 		assertThat(c.getCriteriaObject()).isEqualTo("{ \"name\" : { \"$ne\" : \"Bubba\"}}");
 	}
 
+	@Test // GH-4606
+	void testNotIsCriteria() {
+
+		Criteria c = new Criteria("name").not().is("Bubba");
+		assertThat(c.getCriteriaObject()).isEqualTo("{ \"name\" : { \"$not\" : { \"$eq\" : \"Bubba\"} } }");
+	}
+
+	@Test // GH-4606
+	void testNegatedEqualsCriteria() {
+
+		Criteria c = new Criteria("name").not().eq("Bubba");
+		assertThat(c.getCriteriaObject()).isEqualTo("{ \"name\" : { \"$not\" : { \"$eq\" : \"Bubba\"} } }");
+	}
+
 	@Test
 	void buildsIsNullCriteriaCorrectly() {
 

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/query/QueryTests.java

@@ -57,13 +57,6 @@ void testQueryWithNot() {
 				.isEqualTo(Document.parse("{ \"name\" : \"Thomas\" , \"age\" : { \"$not\" : { \"$mod\" : [ 10 , 0]}}}"));
 	}
 
-	@Test
-	void testInvalidQueryWithNotIs() {
-
-		assertThatExceptionOfType(InvalidMongoDbApiUsageException.class)
-				.isThrownBy(() -> new Query(where("name").not().is("Thomas")));
-	}
-
 	@Test
 	void testOrQuery() {