SimpleAnnotationValueVisitor6.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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package javax.lang.model.util;


import java.util.List;

import javax.annotation.processing.SupportedSourceVersion;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.AnnotationMirror;
import javax.lang.model.element.AnnotationValue;
import javax.lang.model.element.VariableElement;
import javax.lang.model.type.TypeMirror;

import static javax.lang.model.SourceVersion.RELEASE_6;

/**
 * A simple visitor for annotation values with default behavior
 * appropriate for the {@link SourceVersion#RELEASE_6 RELEASE_6}
 * source version.  Visit methods call {@link
 * #defaultAction} passing their arguments to {@code defaultAction}'s
 * corresponding parameters.
 *
 * <p> Methods in this class may be overridden subject to their
 * general contract.  Note that annotating methods in concrete
 * subclasses with {@link java.lang.Override @Override} will help
 * ensure that methods are overridden as intended.
 *
 * <p> <b>WARNING:</b> The {@code AnnotationValueVisitor} interface
 * implemented by this class may have methods added to it in the
 * future to accommodate new, currently unknown, language structures
 * added to future versions of the Java&trade; programming language.
 * Therefore, methods whose names begin with {@code "visit"} may be
 * added to this class in the future; to avoid incompatibilities,
 * classes which extend this class should not declare any instance
 * methods with names beginning with {@code "visit"}.
 *
 * <p>When such a new visit method is added, the default
 * implementation in this class will be to call the {@link
 * #visitUnknown visitUnknown} method.  A new simple annotation
 * value visitor class will also be introduced to correspond to the
 * new language level; this visitor will have different default
 * behavior for the visit method in question.  When the new visitor is
 * introduced, all or portions of this visitor may be deprecated.
 *
 * @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 Ah&eacute;
 * @see SimpleAnnotationValueVisitor7
 * @see SimpleAnnotationValueVisitor8
 * @see SimpleAnnotationValueVisitor9
 * @since 1.6
 */
// 注解值访问器的简单实现（JDK6）
@SupportedSourceVersion(RELEASE_6)
public class SimpleAnnotationValueVisitor6<R, P> extends AbstractAnnotationValueVisitor6<R, P> {
    
    /**
     * Default value to be returned; {@link #defaultAction
     * defaultAction} returns this value unless the method is
     * overridden.
     */
    protected final R DEFAULT_VALUE;
    
    /**
     * Constructor for concrete subclasses; uses {@code null} for the
     * default value.
     *
     * @deprecated Release 6 is obsolete; update to a visitor for a newer
     * release level.
     */
    @Deprecated(since = "9")
    protected SimpleAnnotationValueVisitor6() {
        super();
        DEFAULT_VALUE = null;
    }
    
    /**
     * Constructor for concrete subclasses; uses the argument for the
     * default value.
     *
     * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
     *
     * @deprecated Release 6 is obsolete; update to a visitor for a newer
     * release level.
     */
    @Deprecated(since = "9")
    protected SimpleAnnotationValueVisitor6(R defaultValue) {
        super();
        DEFAULT_VALUE = defaultValue;
    }
    
    /**
     * {@inheritDoc}
     *
     * @param b {@inheritDoc}
     * @param p {@inheritDoc}
     *
     * @return the result of {@code defaultAction}
     *
     * @implSpec This implementation calls {@code defaultAction}.
     */
    public R visitByte(byte b, P p) {
        return defaultAction(b, p);
    }
    
    /**
     * {@inheritDoc}
     *
     * @param s {@inheritDoc}
     * @param p {@inheritDoc}
     *
     * @return the result of {@code defaultAction}
     *
     * @implSpec This implementation calls {@code defaultAction}.
     */
    public R visitShort(short s, P p) {
        return defaultAction(s, p);
    }
    
    /**
     * {@inheritDoc}
     *
     * @param i {@inheritDoc}
     * @param p {@inheritDoc}
     *
     * @return the result of {@code defaultAction}
     *
     * @implSpec This implementation calls {@code defaultAction}.
     */
    public R visitInt(int i, P p) {
        return defaultAction(i, p);
    }
    
    /**
     * {@inheritDoc}
     *
     * @param i {@inheritDoc}
     * @param p {@inheritDoc}
     *
     * @return the result of {@code defaultAction}
     *
     * @implSpec This implementation calls {@code defaultAction}.
     */
    public R visitLong(long i, P p) {
        return defaultAction(i, p);
    }
    
    /**
     * {@inheritDoc}
     *
     * @param c {@inheritDoc}
     * @param p {@inheritDoc}
     *
     * @return the result of {@code defaultAction}
     *
     * @implSpec This implementation calls {@code defaultAction}.
     */
    public R visitChar(char c, P p) {
        return defaultAction(c, p);
    }
    
    /**
     * {@inheritDoc}
     *
     * @param b {@inheritDoc}
     * @param p {@inheritDoc}
     *
     * @return the result of {@code defaultAction}
     *
     * @implSpec This implementation calls {@code defaultAction}.
     */
    public R visitBoolean(boolean b, P p) {
        return defaultAction(b, p);
    }
    
    /**
     * {@inheritDoc}
     *
     * @param f {@inheritDoc}
     * @param p {@inheritDoc}
     *
     * @return the result of {@code defaultAction}
     *
     * @implSpec This implementation calls {@code defaultAction}.
     */
    public R visitFloat(float f, P p) {
        return defaultAction(f, p);
    }
    
    /**
     * {@inheritDoc}
     *
     * @param d {@inheritDoc}
     * @param p {@inheritDoc}
     *
     * @return the result of {@code defaultAction}
     *
     * @implSpec This implementation calls {@code defaultAction}.
     */
    public R visitDouble(double d, P p) {
        return defaultAction(d, p);
    }
    
    /**
     * {@inheritDoc}
     *
     * @param s {@inheritDoc}
     * @param p {@inheritDoc}
     *
     * @return the result of {@code defaultAction}
     *
     * @implSpec This implementation calls {@code defaultAction}.
     */
    public R visitString(String s, P p) {
        return defaultAction(s, p);
    }
    
    /**
     * {@inheritDoc}
     *
     * @param t {@inheritDoc}
     * @param p {@inheritDoc}
     *
     * @return the result of {@code defaultAction}
     *
     * @implSpec This implementation calls {@code defaultAction}.
     */
    public R visitType(TypeMirror t, P p) {
        return defaultAction(t, p);
    }
    
    /**
     * {@inheritDoc}
     *
     * @param c {@inheritDoc}
     * @param p {@inheritDoc}
     *
     * @return the result of {@code defaultAction}
     *
     * @implSpec This implementation calls {@code defaultAction}.
     */
    public R visitEnumConstant(VariableElement c, P p) {
        return defaultAction(c, p);
    }
    
    /**
     * {@inheritDoc}
     *
     * @param a {@inheritDoc}
     * @param p {@inheritDoc}
     *
     * @return the result of {@code defaultAction}
     *
     * @implSpec This implementation calls {@code defaultAction}.
     */
    public R visitAnnotation(AnnotationMirror a, P p) {
        return defaultAction(a, p);
    }
    
    /**
     * {@inheritDoc}
     *
     * @param vals {@inheritDoc}
     * @param p    {@inheritDoc}
     *
     * @return the result of {@code defaultAction}
     *
     * @implSpec This implementation calls {@code defaultAction}.
     */
    public R visitArray(List<? extends AnnotationValue> vals, P p) {
        return defaultAction(vals, p);
    }
    
    /**
     * The default action for visit methods.
     *
     * @param o the value of the annotation
     * @param p a visitor-specified parameter
     *
     * @return {@code DEFAULT_VALUE} unless overridden
     *
     * @implSpec The implementation in this class just returns {@link
     * #DEFAULT_VALUE}; subclasses will commonly override this method.
     */
    protected R defaultAction(Object o, P p) {
        return DEFAULT_VALUE;
    }
}