org.mapstruct.ap.internal.gem.QualifierGem Maven / Gradle / Ivy

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package org.mapstruct.ap.internal.gem;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.lang.model.element.AnnotationMirror;
import javax.lang.model.element.AnnotationValue;
import javax.lang.model.element.Element;
import javax.lang.model.element.ElementKind;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.element.TypeElement;
import javax.lang.model.element.VariableElement;
import javax.lang.model.type.TypeMirror;
import javax.lang.model.util.AbstractAnnotationValueVisitor8;
import javax.lang.model.util.ElementFilter;
import org.mapstruct.tools.gem.Gem;
import org.mapstruct.tools.gem.GemValue;


public class QualifierGem implements Gem {

    private final boolean isValid;
    private final AnnotationMirror mirror;

    private QualifierGem( BuilderImpl builder ) {
        isValid = true;
        mirror = builder.mirror;
    }

    @Override
    public AnnotationMirror mirror( ) {
        return mirror;
    }

    @Override
    public boolean isValid( ) {
        return isValid;
    }

    public static QualifierGem  instanceOn(Element element) {
        return build( element, new BuilderImpl() );
    }

    public static QualifierGem instanceOn(AnnotationMirror mirror ) {
        return build( mirror, new BuilderImpl() );
    }

    public static   T  build(Element element, Builder builder) {
        AnnotationMirror mirror = element.getAnnotationMirrors().stream()
            .filter( a ->  "org.mapstruct.Qualifier".contentEquals( ( ( TypeElement )a.getAnnotationType().asElement() ).getQualifiedName() ) )
            .findAny()
            .orElse( null );
        return build( mirror, builder );
    }

    public static  T build(AnnotationMirror mirror, Builder builder ) {

        // return fast
        if ( mirror == null || builder == null ) {
            return null;
        }
        builder.setMirror( mirror );
        return builder.build();
    }

    /**
     * A builder that can be implemented by the user to define custom logic e.g. in the
     * build method, prior to creating the annotation gem.
     */
    public interface Builder {

        /**
         * Sets the annotation mirror
         *
         * @param mirror the mirror which this gem represents
         *
         * @return the {@link Builder} for this gem, representing {@link QualifierGem}
         */
          Builder setMirror( AnnotationMirror mirror );

        /**
         * The build method can be overriden in a custom custom implementation, which allows
         * the user to define his own custom validation on the annotation.
         *
         * @return the representation of the annotation
         */
        T build();
    }

    private static class BuilderImpl implements Builder {

        private AnnotationMirror mirror;

        public Builder  setMirror( AnnotationMirror mirror ) {
            this.mirror = mirror;
            return this;
        }

        public QualifierGem build() {
            return new QualifierGem( this );
        }
    }

}