001package ball.annotation.processing;
002/*-
003 * ##########################################################################
004 * Utilities
005 * $Id: MustImplement.java 6104 2020-06-03 18:26:30Z ball $
006 * $HeadURL: svn+ssh://svn.hcf.dev/var/spool/scm/repository.svn/ball-util/trunk/src/main/java/ball/annotation/processing/MustImplement.java $
007 * %%
008 * Copyright (C) 2008 - 2020 Allen D. Ball
009 * %%
010 * Licensed under the Apache License, Version 2.0 (the "License");
011 * you may not use this file except in compliance with the License.
012 * You may obtain a copy of the License at
013 *
014 *      http://www.apache.org/licenses/LICENSE-2.0
015 *
016 * Unless required by applicable law or agreed to in writing, software
017 * distributed under the License is distributed on an "AS IS" BASIS,
018 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
019 * See the License for the specific language governing permissions and
020 * limitations under the License.
021 * ##########################################################################
022 */
023import ball.annotation.ServiceProviderFor;
024import java.lang.annotation.Documented;
025import java.lang.annotation.Retention;
026import java.lang.annotation.Target;
027import javax.annotation.processing.Processor;
028import javax.annotation.processing.RoundEnvironment;
029import javax.lang.model.element.AnnotationMirror;
030import javax.lang.model.element.AnnotationValue;
031import javax.lang.model.element.Element;
032import javax.lang.model.element.TypeElement;
033import lombok.NoArgsConstructor;
034import lombok.ToString;
035
036import static java.lang.annotation.ElementType.TYPE;
037import static java.lang.annotation.RetentionPolicy.RUNTIME;
038import static javax.tools.Diagnostic.Kind.ERROR;
039
040/**
041 * {@link java.lang.annotation.Annotation} to specify required
042 * super-{@link Class} criteria a {@link Class} must implement.
043 *
044 * @author {@link.uri mailto:ball@hcf.dev Allen D. Ball}
045 * @version $Revision: 6104 $
046 */
047@Documented
048@Retention(RUNTIME)
049@Target({ TYPE })
050@TargetMustExtend(AnnotatedNoAnnotationProcessor.class)
051public @interface MustImplement {
052    Class<?>[] value() default { };
053
054    /**
055     * {@link Processor} implementation.
056     */
057    @ServiceProviderFor({ Processor.class })
058    @For({ MustImplement.class })
059    @NoArgsConstructor @ToString
060    public static class ProcessorImpl extends AnnotatedProcessor {
061        @Override
062        public void process(RoundEnvironment roundEnv,
063                            TypeElement annotation, Element element) {
064            super.process(roundEnv, annotation, element);
065
066            AnnotationMirror mirror = getAnnotationMirror(element, annotation);
067            AnnotationValue value = getAnnotationValue(mirror, "value");
068
069            if (isEmptyArray(value)) {
070                print(ERROR, element, mirror, value, "value() is empty");
071            }
072        }
073    }
074}