duke@1: /*
ohair@554:  * Copyright (c) 2005, 2008, Oracle and/or its affiliates. All rights reserved.
duke@1:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@1:  *
duke@1:  * This code is free software; you can redistribute it and/or modify it
duke@1:  * under the terms of the GNU General Public License version 2 only, as
ohair@554:  * published by the Free Software Foundation.  Oracle designates this
duke@1:  * particular file as subject to the "Classpath" exception as provided
ohair@554:  * by Oracle in the LICENSE file that accompanied this code.
duke@1:  *
duke@1:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@1:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@1:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@1:  * version 2 for more details (a copy is included in the LICENSE file that
duke@1:  * accompanied this code).
duke@1:  *
duke@1:  * You should have received a copy of the GNU General Public License version
duke@1:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@1:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@1:  *
ohair@554:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
ohair@554:  * or visit www.oracle.com if you need additional information or have any
ohair@554:  * questions.
duke@1:  */
duke@1: 
duke@1: package com.sun.tools.javac.model;
duke@1: 
duke@1: import java.lang.annotation.Annotation;
duke@1: import java.lang.annotation.Inherited;
duke@1: import java.util.Map;
duke@1: import javax.lang.model.SourceVersion;
duke@1: import javax.lang.model.element.*;
duke@1: import javax.lang.model.type.DeclaredType;
duke@1: import javax.lang.model.util.Elements;
duke@1: import javax.tools.JavaFileObject;
duke@1: import com.sun.tools.javac.code.*;
duke@1: import com.sun.tools.javac.code.Symbol.*;
duke@1: import com.sun.tools.javac.code.TypeTags;
duke@1: import com.sun.tools.javac.comp.AttrContext;
duke@1: import com.sun.tools.javac.comp.Enter;
duke@1: import com.sun.tools.javac.comp.Env;
duke@1: import com.sun.tools.javac.main.JavaCompiler;
duke@1: import com.sun.tools.javac.processing.PrintingProcessor;
duke@1: import com.sun.tools.javac.tree.JCTree;
duke@1: import com.sun.tools.javac.tree.JCTree.*;
duke@1: import com.sun.tools.javac.tree.TreeInfo;
duke@1: import com.sun.tools.javac.tree.TreeScanner;
jjg@113: import com.sun.tools.javac.util.*;
duke@1: import com.sun.tools.javac.util.Name;
duke@1: 
duke@1: import static javax.lang.model.util.ElementFilter.methodsIn;
duke@1: 
duke@1: /**
duke@1:  * Utility methods for operating on program elements.
duke@1:  *
jjg@581:  * <p><b>This is NOT part of any supported API.
duke@1:  * If you write code that depends on this, you do so at your own
duke@1:  * risk.  This code and its internal interfaces are subject to change
duke@1:  * or deletion without notice.</b></p>
duke@1:  */
duke@1: public class JavacElements implements Elements {
duke@1: 
duke@1:     private JavaCompiler javaCompiler;
duke@1:     private Symtab syms;
jjg@113:     private Names names;
duke@1:     private Types types;
duke@1:     private Enter enter;
duke@1: 
duke@1:     public static JavacElements instance(Context context) {
jjg@706:         JavacElements instance = context.get(JavacElements.class);
jjg@706:         if (instance == null)
duke@1:             instance = new JavacElements(context);
duke@1:         return instance;
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Public for use only by JavacProcessingEnvironment
duke@1:      */
jjg@706:     protected JavacElements(Context context) {
duke@1:         setContext(context);
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Use a new context.  May be called from outside to update
duke@1:      * internal state for a new annotation-processing round.
duke@1:      */
duke@1:     public void setContext(Context context) {
jjg@706:         context.put(JavacElements.class, this);
duke@1:         javaCompiler = JavaCompiler.instance(context);
duke@1:         syms = Symtab.instance(context);
jjg@113:         names = Names.instance(context);
duke@1:         types = Types.instance(context);
duke@1:         enter = Enter.instance(context);
duke@1:     }
duke@1: 
duke@1: 
duke@1:     /**
duke@1:      * An internal-use utility that creates a reified annotation.
duke@1:      */
duke@1:     public static <A extends Annotation> A getAnnotation(Symbol annotated,
duke@1:                                                          Class<A> annoType) {
duke@1:         if (!annoType.isAnnotation())
duke@1:             throw new IllegalArgumentException("Not an annotation type: "
duke@1:                                                + annoType);
duke@1:         String name = annoType.getName();
duke@1:         for (Attribute.Compound anno : annotated.getAnnotationMirrors())
duke@1:             if (name.equals(anno.type.tsym.flatName().toString()))
duke@1:                 return AnnotationProxyMaker.generateAnnotation(anno, annoType);
duke@1:         return null;
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * An internal-use utility that creates a reified annotation.
duke@1:      * This overloaded version take annotation inheritance into account.
duke@1:      */
duke@1:     public static <A extends Annotation> A getAnnotation(ClassSymbol annotated,
duke@1:                                                          Class<A> annoType) {
duke@1:         boolean inherited = annoType.isAnnotationPresent(Inherited.class);
duke@1:         A result = null;
jjg@113:         while (annotated.name != annotated.name.table.names.java_lang_Object) {
duke@1:             result = getAnnotation((Symbol)annotated, annoType);
duke@1:             if (result != null || !inherited)
duke@1:                 break;
duke@1:             Type sup = annotated.getSuperclass();
duke@1:             if (sup.tag != TypeTags.CLASS || sup.isErroneous())
duke@1:                 break;
duke@1:             annotated = (ClassSymbol) sup.tsym;
duke@1:         }
duke@1:         return result;
duke@1:     }
duke@1: 
duke@1: 
duke@1:     public PackageSymbol getPackageElement(CharSequence name) {
duke@1:         String strName = name.toString();
duke@1:         if (strName.equals(""))
duke@1:             return syms.unnamedPackage;
duke@1:         return SourceVersion.isName(strName)
duke@1:             ? nameToSymbol(strName, PackageSymbol.class)
duke@1:             : null;
duke@1:     }
duke@1: 
duke@1:     public ClassSymbol getTypeElement(CharSequence name) {
duke@1:         String strName = name.toString();
duke@1:         return SourceVersion.isName(strName)
duke@1:             ? nameToSymbol(strName, ClassSymbol.class)
duke@1:             : null;
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Returns a symbol given the type's or packages's canonical name,
duke@1:      * or null if the name isn't found.
duke@1:      */
duke@1:     private <S extends Symbol> S nameToSymbol(String nameStr, Class<S> clazz) {
duke@1:         Name name = names.fromString(nameStr);
duke@1:         // First check cache.
duke@1:         Symbol sym = (clazz == ClassSymbol.class)
duke@1:                     ? syms.classes.get(name)
duke@1:                     : syms.packages.get(name);
duke@1: 
duke@1:         try {
duke@1:             if (sym == null)
duke@1:                 sym = javaCompiler.resolveIdent(nameStr);
duke@1: 
duke@1:             sym.complete();
duke@1: 
duke@1:             return (sym.kind != Kinds.ERR &&
duke@1:                     sym.exists() &&
duke@1:                     clazz.isInstance(sym) &&
duke@1:                     name.equals(sym.getQualifiedName()))
duke@1:                 ? clazz.cast(sym)
duke@1:                 : null;
duke@1:         } catch (CompletionFailure e) {
duke@1:             return null;
duke@1:         }
duke@1:     }
duke@1: 
duke@1:     public JavacSourcePosition getSourcePosition(Element e) {
duke@1:         Pair<JCTree, JCCompilationUnit> treeTop = getTreeAndTopLevel(e);
duke@1:         if (treeTop == null)
duke@1:             return null;
duke@1:         JCTree tree = treeTop.fst;
duke@1:         JCCompilationUnit toplevel = treeTop.snd;
duke@1:         JavaFileObject sourcefile = toplevel.sourcefile;
duke@1:         if (sourcefile == null)
duke@1:             return null;
duke@1:         return new JavacSourcePosition(sourcefile, tree.pos, toplevel.lineMap);
duke@1:     }
duke@1: 
duke@1:     public JavacSourcePosition getSourcePosition(Element e, AnnotationMirror a) {
duke@1:         Pair<JCTree, JCCompilationUnit> treeTop = getTreeAndTopLevel(e);
duke@1:         if (treeTop == null)
duke@1:             return null;
duke@1:         JCTree tree = treeTop.fst;
duke@1:         JCCompilationUnit toplevel = treeTop.snd;
duke@1:         JavaFileObject sourcefile = toplevel.sourcefile;
duke@1:         if (sourcefile == null)
duke@1:             return null;
duke@1: 
duke@1:         JCTree annoTree = matchAnnoToTree(a, e, tree);
duke@1:         if (annoTree == null)
duke@1:             return null;
duke@1:         return new JavacSourcePosition(sourcefile, annoTree.pos,
duke@1:                                        toplevel.lineMap);
duke@1:     }
duke@1: 
duke@1:     public JavacSourcePosition getSourcePosition(Element e, AnnotationMirror a,
duke@1:                                             AnnotationValue v) {
duke@1:         // TODO: better accuracy in getSourcePosition(... AnnotationValue)
duke@1:         return getSourcePosition(e, a);
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Returns the tree for an annotation given the annotated element
duke@1:      * and the element's own tree.  Returns null if the tree cannot be found.
duke@1:      */
duke@1:     private JCTree matchAnnoToTree(AnnotationMirror findme,
duke@1:                                    Element e, JCTree tree) {
duke@1:         Symbol sym = cast(Symbol.class, e);
duke@1:         class Vis extends JCTree.Visitor {
duke@1:             List<JCAnnotation> result = null;
duke@1:             public void visitTopLevel(JCCompilationUnit tree) {
duke@1:                 result = tree.packageAnnotations;
duke@1:             }
duke@1:             public void visitClassDef(JCClassDecl tree) {
duke@1:                 result = tree.mods.annotations;
duke@1:             }
duke@1:             public void visitMethodDef(JCMethodDecl tree) {
duke@1:                 result = tree.mods.annotations;
duke@1:             }
duke@1:             public void visitVarDef(JCVariableDecl tree) {
duke@1:                 result = tree.mods.annotations;
duke@1:             }
duke@1:         }
duke@1:         Vis vis = new Vis();
duke@1:         tree.accept(vis);
duke@1:         if (vis.result == null)
duke@1:             return null;
duke@1:         return matchAnnoToTree(cast(Attribute.Compound.class, findme),
duke@1:                                sym.getAnnotationMirrors(),
duke@1:                                vis.result);
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Returns the tree for an annotation given a list of annotations
duke@1:      * in which to search (recursively) and their corresponding trees.
duke@1:      * Returns null if the tree cannot be found.
duke@1:      */
duke@1:     private JCTree matchAnnoToTree(Attribute.Compound findme,
duke@1:                                    List<Attribute.Compound> annos,
duke@1:                                    List<JCAnnotation> trees) {
duke@1:         for (Attribute.Compound anno : annos) {
duke@1:             for (JCAnnotation tree : trees) {
duke@1:                 JCTree match = matchAnnoToTree(findme, anno, tree);
duke@1:                 if (match != null)
duke@1:                     return match;
duke@1:             }
duke@1:         }
duke@1:         return null;
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Returns the tree for an annotation given an Attribute to
duke@1:      * search (recursively) and its corresponding tree.
duke@1:      * Returns null if the tree cannot be found.
duke@1:      */
duke@1:     private JCTree matchAnnoToTree(final Attribute.Compound findme,
duke@1:                                    final Attribute attr,
duke@1:                                    final JCTree tree) {
duke@1:         if (attr == findme)
duke@1:             return (tree.type.tsym == findme.type.tsym) ? tree : null;
duke@1: 
duke@1:         class Vis implements Attribute.Visitor {
duke@1:             JCTree result = null;
duke@1:             public void visitConstant(Attribute.Constant value) {
duke@1:             }
duke@1:             public void visitClass(Attribute.Class clazz) {
duke@1:             }
duke@1:             public void visitCompound(Attribute.Compound anno) {
duke@1:                 for (Pair<MethodSymbol, Attribute> pair : anno.values) {
duke@1:                     JCExpression expr = scanForAssign(pair.fst, tree);
duke@1:                     if (expr != null) {
duke@1:                         JCTree match = matchAnnoToTree(findme, pair.snd, expr);
duke@1:                         if (match != null) {
duke@1:                             result = match;
duke@1:                             return;
duke@1:                         }
duke@1:                     }
duke@1:                 }
duke@1:             }
duke@1:             public void visitArray(Attribute.Array array) {
duke@1:                 if (tree.getTag() == JCTree.NEWARRAY &&
duke@1:                         types.elemtype(array.type).tsym == findme.type.tsym) {
duke@1:                     List<JCExpression> elems = ((JCNewArray) tree).elems;
duke@1:                     for (Attribute value : array.values) {
duke@1:                         if (value == findme) {
duke@1:                             result = elems.head;
duke@1:                             return;
duke@1:                         }
duke@1:                         elems = elems.tail;
duke@1:                     }
duke@1:                 }
duke@1:             }
duke@1:             public void visitEnum(Attribute.Enum e) {
duke@1:             }
duke@1:             public void visitError(Attribute.Error e) {
duke@1:             }
duke@1:         }
duke@1:         Vis vis = new Vis();
duke@1:         attr.accept(vis);
duke@1:         return vis.result;
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Scans for a JCAssign node with a LHS matching a given
duke@1:      * symbol, and returns its RHS.  Does not scan nested JCAnnotations.
duke@1:      */
duke@1:     private JCExpression scanForAssign(final MethodSymbol sym,
duke@1:                                        final JCTree tree) {
duke@1:         class TS extends TreeScanner {
duke@1:             JCExpression result = null;
duke@1:             public void scan(JCTree t) {
duke@1:                 if (t != null && result == null)
duke@1:                     t.accept(this);
duke@1:             }
duke@1:             public void visitAnnotation(JCAnnotation t) {
duke@1:                 if (t == tree)
duke@1:                     scan(t.args);
duke@1:             }
duke@1:             public void visitAssign(JCAssign t) {
duke@1:                 if (t.lhs.getTag() == JCTree.IDENT) {
duke@1:                     JCIdent ident = (JCIdent) t.lhs;
duke@1:                     if (ident.sym == sym)
duke@1:                         result = t.rhs;
duke@1:                 }
duke@1:             }
duke@1:         }
duke@1:         TS scanner = new TS();
duke@1:         tree.accept(scanner);
duke@1:         return scanner.result;
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Returns the tree node corresponding to this element, or null
duke@1:      * if none can be found.
duke@1:      */
duke@1:     public JCTree getTree(Element e) {
duke@1:         Pair<JCTree, ?> treeTop = getTreeAndTopLevel(e);
duke@1:         return (treeTop != null) ? treeTop.fst : null;
duke@1:     }
duke@1: 
duke@1:     public String getDocComment(Element e) {
duke@1:         // Our doc comment is contained in a map in our toplevel,
duke@1:         // indexed by our tree.  Find our enter environment, which gives
duke@1:         // us our toplevel.  It also gives us a tree that contains our
duke@1:         // tree:  walk it to find our tree.  This is painful.
duke@1:         Pair<JCTree, JCCompilationUnit> treeTop = getTreeAndTopLevel(e);
duke@1:         if (treeTop == null)
duke@1:             return null;
duke@1:         JCTree tree = treeTop.fst;
duke@1:         JCCompilationUnit toplevel = treeTop.snd;
duke@1:         if (toplevel.docComments == null)
duke@1:             return null;
duke@1:         return toplevel.docComments.get(tree);
duke@1:     }
duke@1: 
duke@1:     public PackageElement getPackageOf(Element e) {
duke@1:         return cast(Symbol.class, e).packge();
duke@1:     }
duke@1: 
duke@1:     public boolean isDeprecated(Element e) {
duke@1:         Symbol sym = cast(Symbol.class, e);
duke@1:         return (sym.flags() & Flags.DEPRECATED) != 0;
duke@1:     }
duke@1: 
duke@1:     public Name getBinaryName(TypeElement type) {
duke@1:         return cast(TypeSymbol.class, type).flatName();
duke@1:     }
duke@1: 
duke@1:     public Map<MethodSymbol, Attribute> getElementValuesWithDefaults(
duke@1:                                                         AnnotationMirror a) {
duke@1:         Attribute.Compound anno = cast(Attribute.Compound.class, a);
duke@1:         DeclaredType annotype = a.getAnnotationType();
duke@1:         Map<MethodSymbol, Attribute> valmap = anno.getElementValues();
duke@1: 
duke@1:         for (ExecutableElement ex :
duke@1:                  methodsIn(annotype.asElement().getEnclosedElements())) {
duke@1:             MethodSymbol meth = (MethodSymbol) ex;
duke@1:             Attribute defaultValue = meth.getDefaultValue();
duke@1:             if (defaultValue != null && !valmap.containsKey(meth)) {
duke@1:                 valmap.put(meth, defaultValue);
duke@1:             }
duke@1:         }
duke@1:         return valmap;
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * {@inheritDoc}
duke@1:      */
duke@1:     public FilteredMemberList getAllMembers(TypeElement element) {
duke@1:         Symbol sym = cast(Symbol.class, element);
duke@1:         Scope scope = sym.members().dupUnshared();
duke@1:         List<Type> closure = types.closure(sym.asType());
duke@1:         for (Type t : closure)
duke@1:             addMembers(scope, t);
duke@1:         return new FilteredMemberList(scope);
duke@1:     }
duke@1:     // where
duke@1:         private void addMembers(Scope scope, Type type) {
duke@1:             members:
duke@1:             for (Scope.Entry e = type.asElement().members().elems; e != null; e = e.sibling) {
duke@1:                 Scope.Entry overrider = scope.lookup(e.sym.getSimpleName());
duke@1:                 while (overrider.scope != null) {
duke@1:                     if (overrider.sym.kind == e.sym.kind
duke@1:                         && (overrider.sym.flags() & Flags.SYNTHETIC) == 0)
duke@1:                     {
duke@1:                         if (overrider.sym.getKind() == ElementKind.METHOD
duke@1:                         && overrides((ExecutableElement)overrider.sym, (ExecutableElement)e.sym, (TypeElement)type.asElement())) {
duke@1:                             continue members;
duke@1:                         }
duke@1:                     }
duke@1:                     overrider = overrider.next();
duke@1:                 }
duke@1:                 boolean derived = e.sym.getEnclosingElement() != scope.owner;
duke@1:                 ElementKind kind = e.sym.getKind();
duke@1:                 boolean initializer = kind == ElementKind.CONSTRUCTOR
duke@1:                     || kind == ElementKind.INSTANCE_INIT
duke@1:                     || kind == ElementKind.STATIC_INIT;
duke@1:                 if (!derived || (!initializer && e.sym.isInheritedIn(scope.owner, types)))
duke@1:                     scope.enter(e.sym);
duke@1:             }
duke@1:         }
duke@1: 
duke@1:     /**
duke@1:      * Returns all annotations of an element, whether
duke@1:      * inherited or directly present.
duke@1:      *
duke@1:      * @param e  the element being examined
duke@1:      * @return all annotations of the element
duke@1:      */
duke@1:     public List<Attribute.Compound> getAllAnnotationMirrors(Element e) {
duke@1:         Symbol sym = cast(Symbol.class, e);
duke@1:         List<Attribute.Compound> annos = sym.getAnnotationMirrors();
duke@1:         while (sym.getKind() == ElementKind.CLASS) {
duke@1:             Type sup = ((ClassSymbol) sym).getSuperclass();
duke@1:             if (sup.tag != TypeTags.CLASS || sup.isErroneous() ||
duke@1:                     sup.tsym == syms.objectType.tsym) {
duke@1:                 break;
duke@1:             }
duke@1:             sym = sup.tsym;
duke@1:             List<Attribute.Compound> oldAnnos = annos;
duke@1:             for (Attribute.Compound anno : sym.getAnnotationMirrors()) {
duke@1:                 if (isInherited(anno.type) &&
duke@1:                         !containsAnnoOfType(oldAnnos, anno.type)) {
duke@1:                     annos = annos.prepend(anno);
duke@1:                 }
duke@1:             }
duke@1:         }
duke@1:         return annos;
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Tests whether an annotation type is @Inherited.
duke@1:      */
duke@1:     private boolean isInherited(Type annotype) {
duke@1:         for (Attribute.Compound anno : annotype.tsym.getAnnotationMirrors()) {
duke@1:             if (anno.type.tsym == syms.inheritedType.tsym)
duke@1:                 return true;
duke@1:         }
duke@1:         return false;
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Tests whether a list of annotations contains an annotation
duke@1:      * of a given type.
duke@1:      */
duke@1:     private static boolean containsAnnoOfType(List<Attribute.Compound> annos,
duke@1:                                               Type type) {
duke@1:         for (Attribute.Compound anno : annos) {
duke@1:             if (anno.type.tsym == type.tsym)
duke@1:                 return true;
duke@1:         }
duke@1:         return false;
duke@1:     }
duke@1: 
duke@1:     public boolean hides(Element hiderEl, Element hideeEl) {
duke@1:         Symbol hider = cast(Symbol.class, hiderEl);
duke@1:         Symbol hidee = cast(Symbol.class, hideeEl);
duke@1: 
duke@1:         // Fields only hide fields; methods only methods; types only types.
duke@1:         // Names must match.  Nothing hides itself (just try it).
duke@1:         if (hider == hidee ||
duke@1:                 hider.kind != hidee.kind ||
duke@1:                 hider.name != hidee.name) {
duke@1:             return false;
duke@1:         }
duke@1: 
duke@1:         // Only static methods can hide other methods.
duke@1:         // Methods only hide methods with matching signatures.
duke@1:         if (hider.kind == Kinds.MTH) {
duke@1:             if (!hider.isStatic() ||
duke@1:                         !types.isSubSignature(hider.type, hidee.type)) {
duke@1:                 return false;
duke@1:             }
duke@1:         }
duke@1: 
duke@1:         // Hider must be in a subclass of hidee's class.
duke@1:         // Note that if M1 hides M2, and M2 hides M3, and M3 is accessible
duke@1:         // in M1's class, then M1 and M2 both hide M3.
duke@1:         ClassSymbol hiderClass = hider.owner.enclClass();
duke@1:         ClassSymbol hideeClass = hidee.owner.enclClass();
duke@1:         if (hiderClass == null || hideeClass == null ||
duke@1:                 !hiderClass.isSubClass(hideeClass, types)) {
duke@1:             return false;
duke@1:         }
duke@1: 
duke@1:         // Hidee must be accessible in hider's class.
duke@1:         // The method isInheritedIn is poorly named:  it checks only access.
duke@1:         return hidee.isInheritedIn(hiderClass, types);
duke@1:     }
duke@1: 
duke@1:     public boolean overrides(ExecutableElement riderEl,
duke@1:                              ExecutableElement rideeEl, TypeElement typeEl) {
duke@1:         MethodSymbol rider = cast(MethodSymbol.class, riderEl);
duke@1:         MethodSymbol ridee = cast(MethodSymbol.class, rideeEl);
duke@1:         ClassSymbol origin = cast(ClassSymbol.class, typeEl);
duke@1: 
duke@1:         return rider.name == ridee.name &&
duke@1: 
duke@1:                // not reflexive as per JLS
duke@1:                rider != ridee &&
duke@1: 
duke@1:                // we don't care if ridee is static, though that wouldn't
duke@1:                // compile
duke@1:                !rider.isStatic() &&
duke@1: 
duke@1:                // Symbol.overrides assumes the following
duke@1:                ridee.isMemberOf(origin, types) &&
duke@1: 
duke@1:                // check access and signatures; don't check return types
duke@1:                rider.overrides(ridee, origin, types, false);
duke@1:     }
duke@1: 
duke@1:     public String getConstantExpression(Object value) {
duke@1:         return Constants.format(value);
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Print a representation of the elements to the given writer in
duke@1:      * the specified order.  The main purpose of this method is for
duke@1:      * diagnostics.  The exact format of the output is <em>not</em>
duke@1:      * specified and is subject to change.
duke@1:      *
duke@1:      * @param w the writer to print the output to
duke@1:      * @param elements the elements to print
duke@1:      */
duke@1:     public void printElements(java.io.Writer w, Element... elements) {
duke@1:         for (Element element : elements)
duke@1:             (new PrintingProcessor.PrintingElementVisitor(w, this)).visit(element).flush();
duke@1:     }
duke@1: 
duke@1:     public Name getName(CharSequence cs) {
jjg@113:         return names.fromString(cs.toString());
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Returns the tree node and compilation unit corresponding to this
duke@1:      * element, or null if they can't be found.
duke@1:      */
duke@1:     private Pair<JCTree, JCCompilationUnit> getTreeAndTopLevel(Element e) {
duke@1:         Symbol sym = cast(Symbol.class, e);
duke@1:         Env<AttrContext> enterEnv = getEnterEnv(sym);
duke@1:         if (enterEnv == null)
duke@1:             return null;
duke@1:         JCTree tree = TreeInfo.declarationFor(sym, enterEnv.tree);
duke@1:         if (tree == null || enterEnv.toplevel == null)
duke@1:             return null;
duke@1:         return new Pair<JCTree,JCCompilationUnit>(tree, enterEnv.toplevel);
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Returns the best approximation for the tree node and compilation unit
duke@1:      * corresponding to the given element, annotation and value.
duke@1:      * If the element is null, null is returned.
duke@1:      * If the annotation is null or cannot be found, the tree node and
duke@1:      * compilation unit for the element is returned.
duke@1:      * If the annotation value is null or cannot be found, the tree node and
duke@1:      * compilation unit for the annotation is returned.
duke@1:      */
duke@1:     public Pair<JCTree, JCCompilationUnit> getTreeAndTopLevel(
duke@1:                       Element e, AnnotationMirror a, AnnotationValue v) {
duke@1:         if (e == null)
duke@1:             return null;
duke@1: 
duke@1:         Pair<JCTree, JCCompilationUnit> elemTreeTop = getTreeAndTopLevel(e);
duke@1:         if (elemTreeTop == null)
duke@1:             return null;
duke@1: 
duke@1:         if (a == null)
duke@1:             return elemTreeTop;
duke@1: 
duke@1:         JCTree annoTree = matchAnnoToTree(a, e, elemTreeTop.fst);
duke@1:         if (annoTree == null)
duke@1:             return elemTreeTop;
duke@1: 
duke@1:         // 6388543: if v != null, we should search within annoTree to find
duke@1:         // the tree matching v. For now, we ignore v and return the tree of
duke@1:         // the annotation.
duke@1:         return new Pair<JCTree, JCCompilationUnit>(annoTree, elemTreeTop.snd);
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Returns a symbol's enter environment, or null if it has none.
duke@1:      */
duke@1:     private Env<AttrContext> getEnterEnv(Symbol sym) {
duke@1:         // Get enclosing class of sym, or sym itself if it is a class
duke@1:         // or package.
duke@1:         TypeSymbol ts = (sym.kind != Kinds.PCK)
duke@1:                         ? sym.enclClass()
duke@1:                         : (PackageSymbol) sym;
duke@1:         return (ts != null)
duke@1:                 ? enter.getEnv(ts)
duke@1:                 : null;
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Returns an object cast to the specified type.
duke@1:      * @throws NullPointerException if the object is {@code null}
duke@1:      * @throws IllegalArgumentException if the object is of the wrong type
duke@1:      */
duke@1:     private static <T> T cast(Class<T> clazz, Object o) {
duke@1:         if (! clazz.isInstance(o))
duke@1:             throw new IllegalArgumentException(o.toString());
duke@1:         return clazz.cast(o);
duke@1:     }
duke@1: }