SimpleAnnotatedTypeVisitor.java

package checkers.types.visitors;

import checkers.types.AnnotatedTypeMirror;
import checkers.types.AnnotatedTypeMirror.*;

/**
 * A simple visitor for {@link AnnotatedTypeMirror}s.
 *
 * @param <R>   The return type of this visitor's methods.
 *              Use {@link Void} for visitors that do not need to return results.
 * @param <P>   the type of the additional parameter to this visitor's methods.
 *              Use {@link Void} for visitors that do not need an additional parameter.
 */
public class SimpleAnnotatedTypeVisitor<R, P> implements AnnotatedTypeVisitor<R, P> {

    /** The default value to return as a default action */
    protected final R DEFAULT_VALUE;

    /**
     * Creates an instance of {@link SimpleAnnotatedTypeVisitor} with
     * default value being {@code null}
     */
    public SimpleAnnotatedTypeVisitor() {
        this(null);
    }

    /**
     * Creates an instance of {@link SimpleAnnotatedTypeVisitor} with
     * the default value being the passed defaultValue
     *
     * @param defaultValue the default value this class should return
     */
    public SimpleAnnotatedTypeVisitor(R defaultValue) {
        this.DEFAULT_VALUE = defaultValue;
    }

    /**
     * Performs the default action for visiting trees, if subclasses do not
     * override the visitFOO node.
     *
     * This implementation merely returns the default value (as specified by the
     * protected field {@code DEFAULT_VALUE}).
     */
    protected R defaultAction(AnnotatedTypeMirror type, P p) {
        return DEFAULT_VALUE;
    }

    @Override
    public R visit(AnnotatedTypeMirror type) {
        return visit(type, null);
    }

    @Override
    public R visit(AnnotatedTypeMirror type, P p) {
        return (type == null) ? null : type.accept(this, p);
    }

    @Override
    public R visitDeclared(AnnotatedDeclaredType type, P p) {
        return defaultAction(type, p);
    }

    @Override
    public R visitArray(AnnotatedArrayType type, P p) {
        return defaultAction(type, p);
    }

    @Override
    public R visitExecutable(AnnotatedExecutableType type, P p) {
        return defaultAction(type, p);
    }

    @Override
    public R visitTypeVariable(AnnotatedTypeVariable type, P p) {
        return defaultAction(type, p);
    }

    @Override
    public R visitWildcard(AnnotatedWildcardType type, P p) {
        return defaultAction(type, p);
    }

    @Override
    public R visitPrimitive(AnnotatedPrimitiveType type, P p) {
        return defaultAction(type, p);
    }

    @Override
    public R visitNull(AnnotatedNullType type, P p) {
        return defaultAction(type, p);
    }

    @Override
    public R visitNoType(AnnotatedNoType type, P p) {
        return defaultAction(type, p);
    }
}