NTDVisitor.java

package testlib.nontopdefault;

import com.sun.source.tree.Tree;
import org.checkerframework.common.basetype.BaseTypeChecker;
import org.checkerframework.common.basetype.BaseTypeVisitor;
import org.checkerframework.framework.type.AnnotatedTypeMirror.AnnotatedDeclaredType;
import testlib.nontopdefault.qual.NTDBottom;
import testlib.nontopdefault.qual.NTDMiddle;

public class NTDVisitor extends BaseTypeVisitor<NTDAnnotatedTypeFactory> {
    public NTDVisitor(BaseTypeChecker checker) {
        super(checker);
    }

    // Because classes and interfaces are by default NTDMiddle, an override is defined here which
    // allows references to be declared using any NDT type except NTDBottom.
    @Override
    public boolean isValidUse(
            AnnotatedDeclaredType declarationType, AnnotatedDeclaredType useType, Tree tree) {
        // eg for the statement "@NTDSide Double x;" the declarationType is @NTDMiddle
        // Double, and the useType is @NTDSide Double
        if (declarationType.getEffectiveAnnotation(NTDMiddle.class) != null
                && useType.getEffectiveAnnotation(NTDBottom.class) == null) {
            return true;
        } else {
            // otherwise check the usage using super
            return super.isValidUse(declarationType, useType, tree);
        }
    }
}