DATAMONGO-2282 - Add shortcut to create JsonSchemaProperty for ObjectId.

Original pull request: #757.

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/schema/JsonSchemaProperty.java

@@ -90,6 +90,18 @@ public interface JsonSchemaProperty extends JsonSchemaObject {
 		return new ObjectJsonSchemaProperty(identifier, JsonSchemaObject.object());
 	}
 
+	/**
+	 * Creates a new {@link JsonSchemaProperty} with given {@literal identifier} of {@code bsonType : 'objectId'}.
+	 *
+	 * @param identifier the {@literal property} name or {@literal patternProperty} regex. Must not be {@literal null} nor
+	 *          {@literal empty}.
+	 * @return new instance of {@link JsonSchemaProperty}.
+	 * @since 2.2
+	 */
+	static JsonSchemaProperty objectId(String identifier) {
+		return JsonSchemaProperty.named(identifier).ofType(Type.objectIdType());
+	}
+
 	/**
 	 * Creates a new {@link NumericJsonSchemaProperty} with given {@literal identifier} of {@code type : 'number'}.
 	 *

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/schema/JsonSchemaPropertyUnitTests.java

@@ -63,4 +63,9 @@ public class JsonSchemaPropertyUnitTests {
 	public void shouldRenderTimestampCorrectly() {
 		assertThat(JsonSchemaProperty.timestamp("foo").toDocument()).containsEntry("foo.bsonType", "timestamp");
 	}
+
+	@Test // DATAMONGO-2282
+	public void objectIdShouldBeRenderedCorrectly() {
+		assertThat(JsonSchemaProperty.objectId("_id").toDocument()).containsEntry("_id.bsonType", "objectId");
+	}
 }