1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache license, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the license for the specific language governing permissions and
15 * limitations under the license.
16 */
17
18 package org.apache.logging.log4j.core.config.plugins.validation.constraints;
19
20 import java.lang.annotation.Documented;
21 import java.lang.annotation.ElementType;
22 import java.lang.annotation.Retention;
23 import java.lang.annotation.RetentionPolicy;
24 import java.lang.annotation.Target;
25
26 import org.apache.logging.log4j.core.config.plugins.validation.Constraint;
27 import org.apache.logging.log4j.core.config.plugins.validation.validators.RequiredValidator;
28
29 /**
30 * Marks a plugin builder field or plugin factory parameter as required.
31 *
32 * @since 2.1
33 */
34 @Documented
35 @Retention(RetentionPolicy.RUNTIME)
36 @Target({ElementType.FIELD, ElementType.PARAMETER})
37 @Constraint(RequiredValidator.class)
38 public @interface Required {
39
40 /**
41 * The message to be logged if this constraint is violated. This should normally be overridden.
42 */
43 String message() default "The parameter is null";
44 }