/*
 * Copyright 2008-present MongoDB, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.mongodb.lang;

import javax.annotation.Nonnull;
import javax.annotation.meta.TypeQualifierNickname;
import javax.annotation.meta.When;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

A common annotation to declare that annotated elements can be null under some circumstance. Leverages JSR 305 meta-annotations to indicate nullability in Java to common tools with JSR 305 support and used by Kotlin to infer nullability of Spring API. 
Should be used at parameter, return value, and field level. Methods override should repeat parent @Nullable annotations unless they behave differently.
Can be used in association with NonNullApi to override the default non-nullable semantic to nullable.
See Also:
NonNullApi
NonNull
Since:
3.7/**
 * A common annotation to declare that annotated elements can be {@code null} under some circumstance. Leverages JSR 305 meta-annotations to
 * indicate nullability in Java to common tools with JSR 305 support and used by Kotlin to infer nullability of Spring API.
 *
 * <p>Should be used at parameter, return value, and field level. Methods override should repeat parent {@code @Nullable} annotations
 * unless they behave differently.</p>
 *
 * <p>Can be used in association with {@code NonNullApi} to override the default non-nullable semantic to nullable.</p>
 *
 * @see NonNullApi
 * @see NonNull
 * @since 3.7
 */
@Target({ElementType.METHOD, ElementType.PARAMETER, ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Nonnull(when = When.MAYBE)
@TypeQualifierNickname
public @interface Nullable {
}