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package javax.lang.model.util;

import javax.lang.model.element.*;
import javax.annotation.processing.SupportedSourceVersion;
import javax.lang.model.SourceVersion;
import static javax.lang.model.SourceVersion.*;


A simple visitor of program elements with default behavior appropriate for the RELEASE_6 source version. Visit methods corresponding to RELEASE_6 language constructs call defaultAction, passing their arguments to defaultAction's corresponding parameters. For constructs introduced in RELEASE_7 and later, visitUnknown is called instead.

Methods in this class may be overridden subject to their general contract. Note that annotating methods in concrete subclasses with @Override will help ensure that methods are overridden as intended.

WARNING: The ElementVisitor 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™ programming language. Therefore, methods whose names begin with "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 "visit".

When such a new visit method is added, the default implementation in this class will be to call the visitUnknown method. A new simple element 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.

Author:Joseph D. Darcy, Scott Seligman, Peter von der Ahé
Type parameters:
  • <R> – the return type of this visitor's methods. Use Void for visitors that do not need to return results.
  • <P> – the type of the additional parameter to this visitor's methods. Use Void for visitors that do not need an additional parameter.
See Also:
Since:1.6
/** * A simple visitor of program elements with default behavior * appropriate for the {@link SourceVersion#RELEASE_6 RELEASE_6} * source version. * * Visit methods corresponding to {@code RELEASE_6} language * constructs call {@link #defaultAction defaultAction}, passing their * arguments to {@code defaultAction}'s corresponding parameters. * * For constructs introduced in {@code RELEASE_7} and later, {@code * visitUnknown} is called instead. * * <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 ElementVisitor} 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 element 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. Use {@code Void} * for visitors that do not need to return results. * @param <P> the type of the additional parameter to this visitor's methods. Use {@code Void} * for visitors that do not need an additional parameter. * * @author Joseph D. Darcy * @author Scott Seligman * @author Peter von der Ah&eacute; * * @see SimpleElementVisitor7 * @see SimpleElementVisitor8 * @see SimpleElementVisitor9 * @see SimpleElementVisitor14 * @since 1.6 */
@SupportedSourceVersion(RELEASE_6) public class SimpleElementVisitor6<R, P> extends AbstractElementVisitor6<R, P> {
Default value to be returned; defaultAction returns this value unless the method is overridden.
/** * 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 null for the default value.
Deprecated:Release 6 is obsolete; update to a visitor for a newer release level.
/** * 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 SimpleElementVisitor6(){ DEFAULT_VALUE = null; }
Constructor for concrete subclasses; uses the argument for the default value.
Params:
Deprecated:Release 6 is obsolete; update to a visitor for a newer release level.
/** * 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 SimpleElementVisitor6(R defaultValue){ DEFAULT_VALUE = defaultValue; }
The default action for visit methods.
Params:
  • e – the element to process
  • p – a visitor-specified parameter
Implementation Requirements:The implementation in this class just returns SimpleElementVisitor6<R,P>.DEFAULT_VALUE; subclasses will commonly override this method.
Returns:DEFAULT_VALUE unless overridden
/** * The default action for visit methods. * * @implSpec The implementation in this class just returns {@link * #DEFAULT_VALUE}; subclasses will commonly override this method. * * @param e the element to process * @param p a visitor-specified parameter * @return {@code DEFAULT_VALUE} unless overridden */
protected R defaultAction(Element e, P p) { return DEFAULT_VALUE; }
{@inheritDoc}
Params:
  • e – {@inheritDoc}
  • p – {@inheritDoc}
Implementation Requirements:This implementation calls defaultAction.
Returns: {@inheritDoc}
/** * {@inheritDoc} * * @implSpec This implementation calls {@code defaultAction}. * * @param e {@inheritDoc} * @param p {@inheritDoc} * @return {@inheritDoc} */
public R visitPackage(PackageElement e, P p) { return defaultAction(e, p); }
{@inheritDoc}
Params:
  • e – {@inheritDoc}
  • p – {@inheritDoc}
Implementation Requirements:This implementation calls defaultAction.
Returns: {@inheritDoc}
/** * {@inheritDoc} * * @implSpec This implementation calls {@code defaultAction}. * * @param e {@inheritDoc} * @param p {@inheritDoc} * @return {@inheritDoc} */
public R visitType(TypeElement e, P p) { return defaultAction(e, p); }
{@inheritDoc}
Params:
  • e – {@inheritDoc}
  • p – {@inheritDoc}
Implementation Requirements:This implementation calls defaultAction, unless the element is a RESOURCE_VARIABLE in which case visitUnknown is called.
Returns: {@inheritDoc}
/** * {@inheritDoc} * * @implSpec This implementation calls {@code defaultAction}, unless the * element is a {@code RESOURCE_VARIABLE} in which case {@code * visitUnknown} is called. * * @param e {@inheritDoc} * @param p {@inheritDoc} * @return {@inheritDoc} */
public R visitVariable(VariableElement e, P p) { if (e.getKind() != ElementKind.RESOURCE_VARIABLE) return defaultAction(e, p); else return visitUnknown(e, p); }
{@inheritDoc}
Params:
  • e – {@inheritDoc}
  • p – {@inheritDoc}
Implementation Requirements:This implementation calls defaultAction.
Returns: {@inheritDoc}
/** * {@inheritDoc} * * @implSpec This implementation calls {@code defaultAction}. * * @param e {@inheritDoc} * @param p {@inheritDoc} * @return {@inheritDoc} */
public R visitExecutable(ExecutableElement e, P p) { return defaultAction(e, p); }
{@inheritDoc}
Params:
  • e – {@inheritDoc}
  • p – {@inheritDoc}
Implementation Requirements:This implementation calls defaultAction.
Returns: {@inheritDoc}
/** * {@inheritDoc} * * @implSpec This implementation calls {@code defaultAction}. * * @param e {@inheritDoc} * @param p {@inheritDoc} * @return {@inheritDoc} */
public R visitTypeParameter(TypeParameterElement e, P p) { return defaultAction(e, p); } }