001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements. See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache license, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License. You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the license for the specific language governing permissions and
015     * limitations under the license.
016     */
017    package org.apache.logging.log4j.core.config.plugins.validation;
018    
019    import java.lang.annotation.Annotation;
020    import java.lang.annotation.Documented;
021    import java.lang.annotation.ElementType;
022    import java.lang.annotation.Retention;
023    import java.lang.annotation.RetentionPolicy;
024    import java.lang.annotation.Target;
025    
026    /**
027     * Meta annotation to mark an annotation as a validation constraint. This annotation must specify a
028     * {@link ConstraintValidator} implementation class that has a default constructor.
029     *
030     * @since 2.1
031     */
032    @Documented
033    @Target(ElementType.ANNOTATION_TYPE)
034    @Retention(RetentionPolicy.RUNTIME)
035    public @interface Constraint {
036    
037        /**
038         * {@link ConstraintValidator} class that implements the validation logic for the annotated constraint annotation.
039         */
040        Class<? extends ConstraintValidator<? extends Annotation>> value();
041    }