001package ball.annotation.processing;
002/*-
003 * ##########################################################################
004 * Utilities
005 * %%
006 * Copyright (C) 2008 - 2022 Allen D. Ball
007 * %%
008 * Licensed under the Apache License, Version 2.0 (the "License");
009 * you may not use this file except in compliance with the License.
010 * You may obtain a copy of the License at
011 *
012 *      http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing, software
015 * distributed under the License is distributed on an "AS IS" BASIS,
016 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
017 * See the License for the specific language governing permissions and
018 * limitations under the License.
019 * ##########################################################################
020 */
021import ball.annotation.ServiceProviderFor;
022import java.lang.annotation.Annotation;
023import java.lang.annotation.Documented;
024import java.lang.annotation.Retention;
025import java.lang.annotation.Target;
026import javax.annotation.processing.Processor;
027import javax.annotation.processing.RoundEnvironment;
028import javax.lang.model.element.AnnotationMirror;
029import javax.lang.model.element.AnnotationValue;
030import javax.lang.model.element.Element;
031import javax.lang.model.element.TypeElement;
032import lombok.NoArgsConstructor;
033import lombok.ToString;
034
035import static java.lang.annotation.ElementType.TYPE;
036import static java.lang.annotation.RetentionPolicy.RUNTIME;
037import static javax.tools.Diagnostic.Kind.ERROR;
038
039/**
040 * {@link AnnotatedProcessor} {@link Annotation} to specify
041 * {@link Annotation}s.
042 *
043 * @author {@link.uri mailto:ball@hcf.dev Allen D. Ball}
044 */
045@Documented
046@Retention(RUNTIME)
047@Target({ TYPE })
048@TargetMustExtend(AnnotatedProcessor.class)
049public @interface For {
050    Class<? extends Annotation>[] value() default { };
051
052    /**
053     * {@link Processor} implementation.
054     */
055    @ServiceProviderFor({ Processor.class })
056    @For({ For.class })
057    @NoArgsConstructor @ToString
058    public static class ProcessorImpl extends AnnotatedProcessor {
059        @Override
060        public void process(RoundEnvironment roundEnv, TypeElement annotation, Element element) {
061            super.process(roundEnv, annotation, element);
062
063            AnnotationMirror mirror = getAnnotationMirror(element, annotation);
064            AnnotationValue value = getAnnotationValue(mirror, "value");
065
066            if (isEmptyArray(value)) {
067                print(ERROR, element, mirror, value, "value() is empty");
068            }
069        }
070    }
071}