jdk8-mips64-public/langtools: comparison src/share/classes/javax/lang/model/util/ElementScanner6.java

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+/*
+* Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* This code is free software; you can redistribute it and/or modify it
+* under the terms of the GNU General Public License version 2 only, as
+* published by the Free Software Foundation.  Oracle designates this
+* particular file as subject to the "Classpath" exception as provided
+* by Oracle in the LICENSE file that accompanied this code.
+*
+* This code is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+* version 2 for more details (a copy is included in the LICENSE file that
+* accompanied this code).
+*
+* You should have received a copy of the GNU General Public License version
+* 2 along with this work; if not, write to the Free Software Foundation,
+* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+*
+* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+* or visit www.oracle.com if you need additional information or have any
+* questions.
+*/
+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 scanning visitor of program elements with default behavior
+* appropriate for the {@link SourceVersion#RELEASE_6 RELEASE_6}
+* source version.  The <tt>visit<i>XYZ</i></tt> methods in this
+* class scan their component elements by calling {@code scan} on
+* their {@linkplain Element#getEnclosedElements enclosed elements},
+* {@linkplain ExecutableElement#getParameters parameters}, etc., as
+* indicated in the individual method specifications.  A subclass can
+* control the order elements are visited by overriding the
+* <tt>visit<i>XYZ</i></tt> methods.  Note that clients of a scanner
+* may get the desired behavior be invoking {@code v.scan(e, p)} rather
+* than {@code v.visit(e, p)} on the root objects of interest.
+*
+* <p>When a subclass overrides a <tt>visit<i>XYZ</i></tt> method, the
+* new method can cause the enclosed elements to be scanned in the
+* default way by calling <tt>super.visit<i>XYZ</i></tt>.  In this
+* fashion, the concrete visitor can control the ordering of traversal
+* over the component elements with respect to the additional
+* processing; for example, consistently calling
+* <tt>super.visit<i>XYZ</i></tt> at the start of the overridden
+* methods will yield a preorder traversal, etc.  If the component
+* elements should be traversed in some other order, instead of
+* calling <tt>super.visit<i>XYZ</i></tt>, an overriding visit method
+* should call {@code scan} with the elements in the desired order.
+*
+* <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 element scanner 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 {@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 {@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 ElementScanner7
+* @see ElementScanner8
+* @since 1.6
+*/
+@SupportedSourceVersion(RELEASE_6)
+public class ElementScanner6<R, P> extends AbstractElementVisitor6<R, P> {
+/**
+* The specified default value.
+*/
+protected final R DEFAULT_VALUE;
+/**
+* Constructor for concrete subclasses; uses {@code null} for the
+* default value.
+*/
+protected ElementScanner6(){
+DEFAULT_VALUE = null;
+}
+/**
+* Constructor for concrete subclasses; uses the argument for the
+* default value.
+*
+* @param defaultValue the default value
+*/
+protected ElementScanner6(R defaultValue){
+DEFAULT_VALUE = defaultValue;
+}
+/**
+* Iterates over the given elements and calls {@link
+* #scan(Element, Object) scan(Element, P)} on each one.  Returns
+* the result of the last call to {@code scan} or {@code
+* DEFAULT_VALUE} for an empty iterable.
+*
+* @param iterable the elements to scan
+* @param  p additional parameter
+* @return the scan of the last element or {@code DEFAULT_VALUE} if no elements
+*/
+public final R scan(Iterable<? extends Element> iterable, P p) {
+R result = DEFAULT_VALUE;
+for(Element e : iterable)
+result = scan(e, p);
+return result;
+}
+/**
+* Processes an element by calling {@code e.accept(this, p)};
+* this method may be overridden by subclasses.
+*
+* @param e the element to scan
+* @param p a scanner-specified parameter
+* @return the result of visiting {@code e}.
+*/
+public R scan(Element e, P p) {
+return e.accept(this, p);
+}
+/**
+* Convenience method equivalent to {@code v.scan(e, null)}.
+*
+* @param e the element to scan
+* @return the result of scanning {@code e}.
+*/
+public final R scan(Element e) {
+return scan(e, null);
+}
+/**
+* {@inheritDoc} This implementation scans the enclosed elements.
+*
+* @param e  {@inheritDoc}
+* @param p  {@inheritDoc}
+* @return the result of scanning
+*/
+public R visitPackage(PackageElement e, P p) {
+return scan(e.getEnclosedElements(), p);
+}
+/**
+* {@inheritDoc} This implementation scans the enclosed elements.
+*
+* @param e  {@inheritDoc}
+* @param p  {@inheritDoc}
+* @return the result of scanning
+*/
+public R visitType(TypeElement e, P p) {
+return scan(e.getEnclosedElements(), p);
+}
+/**
+* {@inheritDoc}
+*
+* This implementation scans the enclosed elements, unless the
+* element is a {@code RESOURCE_VARIABLE} in which case {@code
+* visitUnknown} is called.
+*
+* @param e  {@inheritDoc}
+* @param p  {@inheritDoc}
+* @return the result of scanning
+*/
+public R visitVariable(VariableElement e, P p) {
+if (e.getKind() != ElementKind.RESOURCE_VARIABLE)
+return scan(e.getEnclosedElements(), p);
+else
+return visitUnknown(e, p);
+}
+/**
+* {@inheritDoc} This implementation scans the parameters.
+*
+* @param e  {@inheritDoc}
+* @param p  {@inheritDoc}
+* @return the result of scanning
+*/
+public R visitExecutable(ExecutableElement e, P p) {
+return scan(e.getParameters(), p);
+}
+/**
+* {@inheritDoc} This implementation scans the enclosed elements.
+*
+* @param e  {@inheritDoc}
+* @param p  {@inheritDoc}
+* @return the result of scanning
+*/
+public R visitTypeParameter(TypeParameterElement e, P p) {
+return scan(e.getEnclosedElements(), p);
+}
+}

Mercurial > jdk8-mips64-public > langtools / file comparison

comparison: src/share/classes/javax/lang/model/util/ElementScanner6.java

src/share/classes/javax/lang/model/util/ElementScanner6.java