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/* * @(#)AnnotationValueVisitor.java 1.6 06/07/31 * * Copyright 2006 Sun Microsystems, Inc. All rights reserved. * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. */ package javax.lang.model.element; import java.util.List; import javax.lang.model.type.TypeMirror; /** * A visitor of the values of annotation type elements, using a * variant of the visitor design pattern. Unlike a standard visitor * which dispatches based on the concrete type of a member of a type * hierarchy, this visitor dispatches based on the type of data * stored; there are no distinct subclasses for storing, for example, * {@code boolean} values versus {@code int} values. Classes * implementing this interface are used to operate on a value when the * type of that value is unknown at compile time. When a visitor is * passed to a value's {@link AnnotationValue#accept accept} method, * the <tt>visit<i>XYZ</i></tt> method applicable to that value is * invoked. * * <p> Classes implementing this interface may or may not throw a * {@code NullPointerException} if the additional parameter {@code p} * is {@code null}; see documentation of the implementing class for * details. * * <p> <b>WARNING:</b> It is possible that methods will be added to * this interface to accommodate new, currently unknown, language * structures added to future versions of the Java™ programming * language. Therefore, visitor classes directly implementing this * interface may be source incompatible with future versions of the * platform. To avoid this source incompatibility, visitor * implementations are encouraged to instead extend the appropriate * abstract visitor class that implements this interface. However, an * API should generally use this visitor interface as the type for * parameters, return type, etc. rather than one of the abstract * classes. * * @param <R> the return type of this visitor's methods * @param <P> the type of the additional parameter to this visitor's methods. * @author Joseph D. Darcy * @author Scott Seligman * @author Peter von der Ahé * @version 1.6 06/07/31 * @since 1.6 */ public interface AnnotationValueVisitor<R, P> { /** * Visits an annotation value. * @param av the value to visit * @param p a visitor-specified parameter * @return a visitor-specified result */ R visit(AnnotationValue av, P p); /** * A convenience method equivalent to {@code v.visit(av, null)}. * @param av the value to visit * @return a visitor-specified result */ R visit(AnnotationValue av); /** * Visits a {@code boolean} value in an annotation. * @param b the value being visited * @param p a visitor-specified parameter * @return the result of the visit */ R visitBoolean(boolean b, P p); /** * Visits a {@code byte} value in an annotation. * @param b the value being visited * @param p a visitor-specified parameter * @return the result of the visit */ R visitByte(byte b, P p); /** * Visits a {@code char} value in an annotation. * @param c the value being visited * @param p a visitor-specified parameter * @return the result of the visit */ R visitChar(char c, P p); /** * Visits a {@code double} value in an annotation. * @param d the value being visited * @param p a visitor-specified parameter * @return the result of the visit */ R visitDouble(double d, P p); /** * Visits a {@code float} value in an annotation. * @param f the value being visited * @param p a visitor-specified parameter * @return the result of the visit */ R visitFloat(float f, P p); /** * Visits an {@code int} value in an annotation. * @param i the value being visited * @param p a visitor-specified parameter * @return the result of the visit */ R visitInt(int i, P p); /** * Visits a {@code long} value in an annotation. * @param i the value being visited * @param p a visitor-specified parameter * @return the result of the visit */ R visitLong(long i, P p); /** * Visits a {@code short} value in an annotation. * @param s the value being visited * @param p a visitor-specified parameter * @return the result of the visit */ R visitShort(short s, P p); /** * Visits a string value in an annotation. * @param s the value being visited * @param p a visitor-specified parameter * @return the result of the visit */ R visitString(String s, P p); /** * Visits a type value in an annotation. * @param t the value being visited * @param p a visitor-specified parameter * @return the result of the visit */ R visitType(TypeMirror t, P p); /** * Visits an {@code enum} value in an annotation. * @param c the value being visited * @param p a visitor-specified parameter * @return the result of the visit */ R visitEnumConstant(VariableElement c, P p); /** * Visits an annotation value in an annotation. * @param a the value being visited * @param p a visitor-specified parameter * @return the result of the visit */ R visitAnnotation(AnnotationMirror a, P p); /** * Visits an array value in an annotation. * @param vals the value being visited * @param p a visitor-specified parameter * @return the result of the visit */ R visitArray(List<? extends AnnotationValue> vals, P p); /** * Visits an unknown kind of annotation value. * This can occur if the language evolves and new kinds * of value can be stored in an annotation. * @param av the unknown value being visited * @param p a visitor-specified parameter * @return the result of the visit * @throws UnknownAnnotationValueException * a visitor implementation may optionally throw this exception */ R visitUnknown(AnnotationValue av, P p); }