langtools/src/jdk.jshell/share/classes/jdk/jshell/SourceCodeAnalysisImpl.java
changeset 33362 65ec6de1d6b4
child 33715 74b1bed86932
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/src/jdk.jshell/share/classes/jdk/jshell/SourceCodeAnalysisImpl.java	Mon Oct 19 19:15:16 2015 +0200
@@ -0,0 +1,1000 @@
+/*
+ * Copyright (c) 2014, 2015, 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 jdk.jshell;
+
+import jdk.jshell.SourceCodeAnalysis.Completeness;
+import com.sun.source.tree.AssignmentTree;
+import com.sun.source.tree.CompilationUnitTree;
+import com.sun.source.tree.ErroneousTree;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.IdentifierTree;
+import com.sun.source.tree.ImportTree;
+import com.sun.source.tree.MemberSelectTree;
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.source.tree.MethodTree;
+import com.sun.source.tree.NewClassTree;
+import com.sun.source.tree.Scope;
+import com.sun.source.tree.Tree;
+import com.sun.source.tree.Tree.Kind;
+import com.sun.source.tree.VariableTree;
+import com.sun.source.util.SourcePositions;
+import com.sun.source.util.TreePath;
+import com.sun.source.util.TreePathScanner;
+import com.sun.tools.javac.api.JavacScope;
+import com.sun.tools.javac.code.Flags;
+import com.sun.tools.javac.code.Symbol.CompletionFailure;
+import com.sun.tools.javac.code.Symbol.VarSymbol;
+import com.sun.tools.javac.code.Symtab;
+import com.sun.tools.javac.code.Type;
+import com.sun.tools.javac.code.Type.ClassType;
+import com.sun.tools.javac.util.DefinedBy;
+import com.sun.tools.javac.util.DefinedBy.Api;
+import com.sun.tools.javac.util.Name;
+import com.sun.tools.javac.util.Names;
+import com.sun.tools.javac.util.Pair;
+import jdk.jshell.CompletenessAnalyzer.CaInfo;
+import jdk.jshell.TaskFactory.AnalyzeTask;
+import jdk.jshell.TaskFactory.ParseTask;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.function.Predicate;
+
+import javax.lang.model.element.Element;
+import javax.lang.model.element.ElementKind;
+import javax.lang.model.element.Modifier;
+import javax.lang.model.element.TypeElement;
+import javax.lang.model.type.DeclaredType;
+import javax.lang.model.type.TypeMirror;
+
+import static jdk.internal.jshell.debug.InternalDebugControl.DBG_COMPA;
+
+import java.io.IOException;
+import java.util.Comparator;
+import java.util.EnumSet;
+import java.util.HashSet;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import java.util.function.Function;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import static java.util.stream.Collectors.collectingAndThen;
+import static java.util.stream.Collectors.joining;
+import static java.util.stream.Collectors.toCollection;
+import static java.util.stream.Collectors.toList;
+import static java.util.stream.Collectors.toSet;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+import javax.lang.model.element.ExecutableElement;
+import javax.lang.model.element.PackageElement;
+import javax.lang.model.element.QualifiedNameable;
+import javax.lang.model.element.VariableElement;
+import javax.lang.model.type.ArrayType;
+import javax.lang.model.type.ExecutableType;
+import javax.lang.model.type.TypeKind;
+import javax.lang.model.util.ElementFilter;
+import javax.lang.model.util.Elements;
+import javax.lang.model.util.Types;
+import javax.tools.JavaFileManager.Location;
+import javax.tools.JavaFileObject;
+import javax.tools.StandardLocation;
+
+import static jdk.jshell.Util.REPL_DOESNOTMATTER_CLASS_NAME;
+
+/**
+ * The concrete implementation of SourceCodeAnalysis.
+ * @author Robert Field
+ */
+class SourceCodeAnalysisImpl extends SourceCodeAnalysis {
+    private final JShell proc;
+    private final CompletenessAnalyzer ca;
+
+    SourceCodeAnalysisImpl(JShell proc) {
+        this.proc = proc;
+        this.ca = new CompletenessAnalyzer(proc);
+    }
+
+    @Override
+    public CompletionInfo analyzeCompletion(String srcInput) {
+        MaskCommentsAndModifiers mcm = new MaskCommentsAndModifiers(srcInput, false);
+        String cleared = mcm.cleared();
+        String trimmedInput = Util.trimEnd(cleared);
+        if (trimmedInput.isEmpty()) {
+            // Just comment or empty
+            return new CompletionInfo(Completeness.EMPTY, srcInput.length(), srcInput, "");
+        }
+        CaInfo info = ca.scan(trimmedInput);
+        Completeness status = info.status;
+        int unitEndPos = info.unitEndPos;
+        if (unitEndPos > srcInput.length()) {
+            unitEndPos = srcInput.length();
+        }
+        int nonCommentNonWhiteLength = trimmedInput.length();
+        String src = srcInput.substring(0, unitEndPos);
+        switch (status) {
+            case COMPLETE:
+                if (unitEndPos == nonCommentNonWhiteLength) {
+                    // The unit is the whole non-coment/white input plus semicolon
+                    String compileSource = src
+                            + mcm.mask().substring(nonCommentNonWhiteLength);
+                    proc.debug(DBG_COMPA, "Complete: %s\n", compileSource);
+                    proc.debug(DBG_COMPA, "   nothing remains.\n");
+                    return new CompletionInfo(status, unitEndPos, compileSource, "");
+                } else {
+                    String remain = srcInput.substring(unitEndPos);
+                    proc.debug(DBG_COMPA, "Complete: %s\n", src);
+                    proc.debug(DBG_COMPA, "          remaining: %s\n", remain);
+                    return new CompletionInfo(status, unitEndPos, src, remain);
+                }
+            case COMPLETE_WITH_SEMI:
+                // The unit is the whole non-coment/white input plus semicolon
+                String compileSource = src
+                        + ";"
+                        + mcm.mask().substring(nonCommentNonWhiteLength);
+                proc.debug(DBG_COMPA, "Complete with semi: %s\n", compileSource);
+                proc.debug(DBG_COMPA, "   nothing remains.\n");
+                return new CompletionInfo(status, unitEndPos, compileSource, "");
+            case DEFINITELY_INCOMPLETE:
+                proc.debug(DBG_COMPA, "Incomplete: %s\n", srcInput);
+                return new CompletionInfo(status, unitEndPos, null, srcInput + '\n');
+            case CONSIDERED_INCOMPLETE:
+                proc.debug(DBG_COMPA, "Considered incomplete: %s\n", srcInput);
+                return new CompletionInfo(status, unitEndPos, null, srcInput + '\n');
+            case EMPTY:
+                proc.debug(DBG_COMPA, "Detected empty: %s\n", srcInput);
+                return new CompletionInfo(status, unitEndPos, srcInput, "");
+            case UNKNOWN:
+                proc.debug(DBG_COMPA, "Detected error: %s\n", srcInput);
+                return new CompletionInfo(status, unitEndPos, srcInput, "");
+        }
+        throw new InternalError();
+    }
+
+    private OuterWrap wrapInClass(Wrap guts) {
+        String imports = proc.maps.packageAndImportsExcept(null, null);
+        return OuterWrap.wrapInClass(proc.maps.packageName(), REPL_DOESNOTMATTER_CLASS_NAME, imports, "", guts);
+    }
+
+    private Tree.Kind guessKind(String code) {
+        ParseTask pt = proc.taskFactory.new ParseTask(code);
+        List<? extends Tree> units = pt.units();
+        if (units.isEmpty()) {
+            return Tree.Kind.BLOCK;
+        }
+        Tree unitTree = units.get(0);
+        proc.debug(DBG_COMPA, "Kind: %s -- %s\n", unitTree.getKind(), unitTree);
+        return unitTree.getKind();
+    }
+
+    //TODO: would be better handled through a lexer:
+    private final Pattern JAVA_IDENTIFIER = Pattern.compile("\\p{javaJavaIdentifierStart}\\p{javaJavaIdentifierPart}*");
+
+    @Override
+    public List<Suggestion> completionSuggestions(String code, int cursor, int[] anchor) {
+        code = code.substring(0, cursor);
+        Matcher m = JAVA_IDENTIFIER.matcher(code);
+        String identifier = "";
+        while (m.find()) {
+            if (m.end() == code.length()) {
+                cursor = m.start();
+                code = code.substring(0, cursor);
+                identifier = m.group();
+            }
+        }
+        code = code.substring(0, cursor);
+        if (code.trim().isEmpty()) { //TODO: comment handling
+            code += ";";
+        }
+        OuterWrap codeWrap;
+        switch (guessKind(code)) {
+            case IMPORT:
+                codeWrap = OuterWrap.wrapImport(null, Wrap.importWrap(code + "any.any"));
+                break;
+            case METHOD:
+                codeWrap = wrapInClass(Wrap.classMemberWrap(code));
+                break;
+            default:
+                codeWrap = wrapInClass(Wrap.methodWrap(code));
+                break;
+        }
+        String requiredPrefix = identifier;
+        return computeSuggestions(codeWrap, cursor, anchor).stream()
+                .filter(s -> s.continuation.startsWith(requiredPrefix) && !s.continuation.equals(REPL_DOESNOTMATTER_CLASS_NAME))
+                .sorted(Comparator.comparing(s -> s.continuation))
+                .collect(collectingAndThen(toList(), Collections::unmodifiableList));
+    }
+
+    private List<Suggestion> computeSuggestions(OuterWrap code, int cursor, int[] anchor) {
+        AnalyzeTask at = proc.taskFactory.new AnalyzeTask(code);
+        SourcePositions sp = at.trees().getSourcePositions();
+        CompilationUnitTree topLevel = at.cuTree();
+        List<Suggestion> result = new ArrayList<>();
+        TreePath tp = pathFor(topLevel, sp, code.snippetIndexToWrapIndex(cursor));
+        if (tp != null) {
+            Scope scope = at.trees().getScope(tp);
+            Predicate<Element> accessibility = createAccessibilityFilter(at, tp);
+            Predicate<Element> smartTypeFilter;
+            Predicate<Element> smartFilter;
+            Iterable<TypeMirror> targetTypes = findTargetType(at, tp);
+            if (targetTypes != null) {
+                smartTypeFilter = el -> {
+                    TypeMirror resultOf = resultTypeOf(el);
+                    return Util.stream(targetTypes)
+                            .anyMatch(targetType -> at.getTypes().isAssignable(resultOf, targetType));
+                };
+
+                smartFilter = IS_CLASS.negate()
+                                      .and(IS_INTERFACE.negate())
+                                      .and(IS_PACKAGE.negate())
+                                      .and(smartTypeFilter);
+            } else {
+                smartFilter = TRUE;
+                smartTypeFilter = TRUE;
+            }
+            switch (tp.getLeaf().getKind()) {
+                case MEMBER_SELECT: {
+                    MemberSelectTree mst = (MemberSelectTree)tp.getLeaf();
+                    if (mst.getIdentifier().contentEquals("*"))
+                        break;
+                    TreePath exprPath = new TreePath(tp, mst.getExpression());
+                    TypeMirror site = at.trees().getTypeMirror(exprPath);
+                    boolean staticOnly = isStaticContext(at, exprPath);
+                    ImportTree it = findImport(tp);
+                    boolean isImport = it != null;
+
+                    List<? extends Element> members = membersOf(at, site, staticOnly && !isImport);
+                    Predicate<Element> filter = accessibility;
+                    Function<Boolean, String> paren = DEFAULT_PAREN;
+
+                    if (isNewClass(tp)) { // new xxx.|
+                        Predicate<Element> constructorFilter = accessibility.and(IS_CONSTRUCTOR)
+                            .and(el -> {
+                                if (el.getEnclosingElement().getEnclosingElement().getKind() == ElementKind.CLASS) {
+                                    return el.getEnclosingElement().getModifiers().contains(Modifier.STATIC);
+                                }
+                                return true;
+                            });
+                        addElements(membersOf(at, members), constructorFilter, smartFilter, result);
+
+                        filter = filter.and(IS_PACKAGE);
+                    } else if (isThrowsClause(tp)) {
+                        staticOnly = true;
+                        filter = filter.and(IS_PACKAGE.or(IS_CLASS).or(IS_INTERFACE));
+                        smartFilter = IS_PACKAGE.negate().and(smartTypeFilter);
+                    } else if (isImport) {
+                        paren = NO_PAREN;
+                        if (!it.isStatic()) {
+                            filter = filter.and(IS_PACKAGE.or(IS_CLASS).or(IS_INTERFACE));
+                        }
+                    } else {
+                        filter = filter.and(IS_CONSTRUCTOR.negate());
+                    }
+
+                    filter = filter.and(staticOnly ? STATIC_ONLY : INSTANCE_ONLY);
+
+                    addElements(members, filter, smartFilter, paren, result);
+                    break;
+                }
+                case IDENTIFIER:
+                    if (isNewClass(tp)) {
+                        Function<Element, Iterable<? extends Element>> listEnclosed =
+                                el -> el.getKind() == ElementKind.PACKAGE ? Collections.singletonList(el)
+                                                                          : el.getEnclosedElements();
+                        Predicate<Element> filter = accessibility.and(IS_CONSTRUCTOR.or(IS_PACKAGE));
+                        NewClassTree newClassTree = (NewClassTree)tp.getParentPath().getLeaf();
+                        ExpressionTree enclosingExpression = newClassTree.getEnclosingExpression();
+                        if (enclosingExpression != null) { // expr.new IDENT|
+                            TypeMirror site = at.trees().getTypeMirror(new TreePath(tp, enclosingExpression));
+                            filter = filter.and(el -> el.getEnclosingElement().getKind() == ElementKind.CLASS && !el.getEnclosingElement().getModifiers().contains(Modifier.STATIC));
+                            addElements(membersOf(at, membersOf(at, site, false)), filter, smartFilter, result);
+                        } else {
+                            addScopeElements(at, scope, listEnclosed, filter, smartFilter, result);
+                        }
+                        break;
+                    }
+                    if (isThrowsClause(tp)) {
+                        Predicate<Element> accept = accessibility.and(STATIC_ONLY)
+                                .and(IS_PACKAGE.or(IS_CLASS).or(IS_INTERFACE));
+                        addScopeElements(at, scope, IDENTITY, accept, IS_PACKAGE.negate().and(smartTypeFilter), result);
+                        break;
+                    }
+                    ImportTree it = findImport(tp);
+                    if (it != null) {
+                        addElements(membersOf(at, at.getElements().getPackageElement("").asType(), false), it.isStatic() ? STATIC_ONLY.and(accessibility) : accessibility, smartFilter, result);
+                    }
+                    break;
+                case ERRONEOUS:
+                case EMPTY_STATEMENT: {
+                    boolean staticOnly = ReplResolve.isStatic(((JavacScope)scope).getEnv());
+                    Predicate<Element> accept = accessibility.and(staticOnly ? STATIC_ONLY : TRUE);
+                    addScopeElements(at, scope, IDENTITY, accept, smartFilter, result);
+
+                    Tree parent = tp.getParentPath().getLeaf();
+                    switch (parent.getKind()) {
+                        case VARIABLE:
+                            accept = ((VariableTree)parent).getType() == tp.getLeaf() ?
+                                    IS_VOID.negate() :
+                                    TRUE;
+                            break;
+                        case PARAMETERIZED_TYPE: // TODO: JEP 218: Generics over Primitive Types
+                        case TYPE_PARAMETER:
+                        case CLASS:
+                        case INTERFACE:
+                        case ENUM:
+                            accept = FALSE;
+                            break;
+                        default:
+                            accept = TRUE;
+                            break;
+                    }
+                    addElements(primitivesOrVoid(at), accept, smartFilter, result);
+                    break;
+                }
+            }
+        }
+        anchor[0] = cursor;
+        return result;
+    }
+
+    private boolean isStaticContext(AnalyzeTask at, TreePath path) {
+        switch (path.getLeaf().getKind()) {
+            case ARRAY_TYPE:
+            case PRIMITIVE_TYPE:
+                return true;
+            default:
+                Element selectEl = at.trees().getElement(path);
+                return selectEl != null && (selectEl.getKind().isClass() || selectEl.getKind().isInterface() || selectEl.getKind() == ElementKind.TYPE_PARAMETER) && selectEl.asType().getKind() != TypeKind.ERROR;
+        }
+    }
+
+    private TreePath pathFor(CompilationUnitTree topLevel, SourcePositions sp, int pos) {
+        TreePath[] deepest = new TreePath[1];
+
+        new TreePathScanner<Void, Void>() {
+            @Override @DefinedBy(Api.COMPILER_TREE)
+            public Void scan(Tree tree, Void p) {
+                if (tree == null)
+                    return null;
+
+                long start = sp.getStartPosition(topLevel, tree);
+                long end = sp.getEndPosition(topLevel, tree);
+
+                if (start <= pos && pos <= end) {
+                    deepest[0] = new TreePath(getCurrentPath(), tree);
+                    return super.scan(tree, p);
+                }
+
+                return null;
+            }
+            @Override @DefinedBy(Api.COMPILER_TREE)
+            public Void visitErroneous(ErroneousTree node, Void p) {
+                return scan(node.getErrorTrees(), null);
+            }
+        }.scan(topLevel, null);
+
+        return deepest[0];
+    }
+
+    private boolean isNewClass(TreePath tp) {
+        return tp.getParentPath() != null &&
+               tp.getParentPath().getLeaf().getKind() == Kind.NEW_CLASS &&
+               ((NewClassTree) tp.getParentPath().getLeaf()).getIdentifier() == tp.getLeaf();
+    }
+
+    private boolean isThrowsClause(TreePath tp) {
+        Tree parent = tp.getParentPath().getLeaf();
+        return parent.getKind() == Kind.METHOD &&
+                ((MethodTree)parent).getThrows().contains(tp.getLeaf());
+    }
+
+    private ImportTree findImport(TreePath tp) {
+        while (tp != null && tp.getLeaf().getKind() != Kind.IMPORT) {
+            tp = tp.getParentPath();
+        }
+        return tp != null ? (ImportTree)tp.getLeaf() : null;
+    }
+
+    private Predicate<Element> createAccessibilityFilter(AnalyzeTask at, TreePath tp) {
+        Scope scope = at.trees().getScope(tp);
+        return el -> {
+            switch (el.getKind()) {
+                case ANNOTATION_TYPE: case CLASS: case ENUM: case INTERFACE:
+                    return at.trees().isAccessible(scope, (TypeElement) el);
+                case PACKAGE:
+                case EXCEPTION_PARAMETER: case PARAMETER: case LOCAL_VARIABLE: case RESOURCE_VARIABLE:
+                    return true;
+                default:
+                    TypeMirror type = el.getEnclosingElement().asType();
+                    if (type.getKind() == TypeKind.DECLARED)
+                        return at.trees().isAccessible(scope, el, (DeclaredType) type);
+                    else
+                        return true;
+            }
+        };
+    }
+
+    private final Predicate<Element> TRUE = el -> true;
+    private final Predicate<Element> FALSE = TRUE.negate();
+    private final Predicate<Element> IS_STATIC = el -> el.getModifiers().contains(Modifier.STATIC);
+    private final Predicate<Element> IS_CONSTRUCTOR = el -> el.getKind() == ElementKind.CONSTRUCTOR;
+    private final Predicate<Element> IS_METHOD = el -> el.getKind() == ElementKind.METHOD;
+    private final Predicate<Element> IS_PACKAGE = el -> el.getKind() == ElementKind.PACKAGE;
+    private final Predicate<Element> IS_CLASS = el -> el.getKind().isClass();
+    private final Predicate<Element> IS_INTERFACE = el -> el.getKind().isInterface();
+    private final Predicate<Element> IS_VOID = el -> el.asType().getKind() == TypeKind.VOID;
+    private final Predicate<Element> STATIC_ONLY = el -> {
+        ElementKind kind = el.getKind();
+        Element encl = el.getEnclosingElement();
+        ElementKind enclKind = encl != null ? encl.getKind() : ElementKind.OTHER;
+
+        return IS_STATIC.or(IS_PACKAGE).or(IS_CLASS).or(IS_INTERFACE).test(el) || IS_PACKAGE.test(encl) ||
+                (kind == ElementKind.TYPE_PARAMETER && !enclKind.isClass() && !enclKind.isInterface());
+    };
+    private final Predicate<Element> INSTANCE_ONLY = el -> {
+        Element encl = el.getEnclosingElement();
+
+        return IS_STATIC.or(IS_CLASS).or(IS_INTERFACE).negate().test(el) ||
+                IS_PACKAGE.test(encl);
+    };
+    private final Function<Element, Iterable<? extends Element>> IDENTITY = el -> Collections.singletonList(el);
+    private final Function<Boolean, String> DEFAULT_PAREN = hasParams -> hasParams ? "(" : "()";
+    private final Function<Boolean, String> NO_PAREN = hasParams -> "";
+
+    private void addElements(Iterable<? extends Element> elements, Predicate<Element> accept, Predicate<Element> smart, List<Suggestion> result) {
+        addElements(elements, accept, smart, DEFAULT_PAREN, result);
+    }
+    private void addElements(Iterable<? extends Element> elements, Predicate<Element> accept, Predicate<Element> smart, Function<Boolean, String> paren, List<Suggestion> result) {
+        Set<String> hasParams = Util.stream(elements)
+                .filter(accept)
+                .filter(IS_CONSTRUCTOR.or(IS_METHOD))
+                .filter(c -> !((ExecutableElement)c).getParameters().isEmpty())
+                .map(this::simpleName)
+                .collect(toSet());
+
+        for (Element c : elements) {
+            if (!accept.test(c))
+                continue;
+            String simpleName = simpleName(c);
+            if (c.getKind() == ElementKind.CONSTRUCTOR || c.getKind() == ElementKind.METHOD) {
+                simpleName += paren.apply(hasParams.contains(simpleName));
+            }
+            result.add(new Suggestion(simpleName, smart.test(c)));
+        }
+    }
+
+    private String simpleName(Element el) {
+        return el.getKind() == ElementKind.CONSTRUCTOR ? el.getEnclosingElement().getSimpleName().toString()
+                                                       : el.getSimpleName().toString();
+    }
+
+    private List<? extends Element> membersOf(AnalyzeTask at, TypeMirror site, boolean shouldGenerateDotClassItem) {
+        if (site  == null)
+            return Collections.emptyList();
+
+        switch (site.getKind()) {
+            case DECLARED: {
+                TypeElement element = (TypeElement) at.getTypes().asElement(site);
+                List<Element> result = new ArrayList<>();
+                result.addAll(at.getElements().getAllMembers(element));
+                if (shouldGenerateDotClassItem) {
+                    result.add(createDotClassSymbol(at, site));
+                }
+                result.removeIf(el -> el.getKind() == ElementKind.STATIC_INIT);
+                return result;
+            }
+            case ERROR: {
+                //try current qualified name as a package:
+                TypeElement typeElement = (TypeElement) at.getTypes().asElement(site);
+                Element enclosingElement = typeElement.getEnclosingElement();
+                String parentPackageName = enclosingElement instanceof QualifiedNameable ?
+                    ((QualifiedNameable)enclosingElement).getQualifiedName().toString() :
+                    "";
+                Set<PackageElement> packages = listPackages(at, parentPackageName);
+                return packages.stream()
+                               .filter(p -> p.getQualifiedName().equals(typeElement.getQualifiedName()))
+                               .findAny()
+                               .map(p -> membersOf(at, p.asType(), false))
+                               .orElse(Collections.emptyList());
+            }
+            case PACKAGE: {
+                String packageName = site.toString()/*XXX*/;
+                List<Element> result = new ArrayList<>();
+                result.addAll(getEnclosedElements(at.getElements().getPackageElement(packageName)));
+                result.addAll(listPackages(at, packageName));
+                return result;
+            }
+            case BOOLEAN: case BYTE: case SHORT: case CHAR:
+            case INT: case FLOAT: case LONG: case DOUBLE:
+            case VOID: {
+                return shouldGenerateDotClassItem ?
+                    Collections.singletonList(createDotClassSymbol(at, site)) :
+                    Collections.emptyList();
+            }
+            case ARRAY: {
+                List<Element> result = new ArrayList<>();
+                result.add(createArrayLengthSymbol(at, site));
+                if (shouldGenerateDotClassItem)
+                    result.add(createDotClassSymbol(at, site));
+                return result;
+            }
+            default:
+                return Collections.emptyList();
+        }
+    }
+
+    private List<? extends Element> membersOf(AnalyzeTask at, List<? extends Element> elements) {
+        return elements.stream()
+                .flatMap(e -> membersOf(at, e.asType(), true).stream())
+                .collect(toList());
+    }
+
+    private List<? extends Element> getEnclosedElements(PackageElement packageEl) {
+        if (packageEl == null) {
+            return Collections.emptyList();
+        }
+        //workaround for: JDK-8024687
+        while (true) {
+            try {
+                return packageEl.getEnclosedElements()
+                                .stream()
+                                .filter(el -> el.asType() != null)
+                                .filter(el -> el.asType().getKind() != TypeKind.ERROR)
+                                .collect(toList());
+            } catch (CompletionFailure cf) {
+                //ignore...
+            }
+        }
+    }
+
+    private List<? extends Element> primitivesOrVoid(AnalyzeTask at) {
+        Types types = at.getTypes();
+        return Stream.of(
+                TypeKind.BOOLEAN, TypeKind.BYTE, TypeKind.CHAR,
+                TypeKind.DOUBLE, TypeKind.FLOAT, TypeKind.INT,
+                TypeKind.LONG, TypeKind.SHORT, TypeKind.VOID)
+                .map(tk -> (Type)(tk == TypeKind.VOID ? types.getNoType(tk) : types.getPrimitiveType(tk)))
+                .map(Type::asElement)
+                .collect(toList());
+    }
+
+    private Set<PackageElement> listPackages(AnalyzeTask at, String enclosingPackage) {
+        Set<PackageElement> packs = new HashSet<>();
+        listPackages(at, StandardLocation.PLATFORM_CLASS_PATH, enclosingPackage, packs);
+        listPackages(at, StandardLocation.CLASS_PATH, enclosingPackage, packs);
+        listPackages(at, StandardLocation.SOURCE_PATH, enclosingPackage, packs);
+        return packs;
+    }
+
+    private void listPackages(AnalyzeTask at, Location loc, String currentPackage, Set<PackageElement> packs) {
+        try {
+            MemoryFileManager fm = proc.taskFactory.fileManager();
+            for (JavaFileObject file : fm.list(loc, currentPackage, fileKinds, true)) {
+                String binaryName = fm.inferBinaryName(loc, file);
+                if (!currentPackage.isEmpty() && !binaryName.startsWith(currentPackage + "."))
+                    continue;
+                int nextDot = binaryName.indexOf('.', !currentPackage.isEmpty() ? currentPackage.length() + 1 : 0);
+                if (nextDot == (-1))
+                    continue;
+                Elements elements = at.getElements();
+                PackageElement pack =
+                        elements.getPackageElement(binaryName.substring(0, nextDot));
+                if (pack == null) {
+                    //if no types in the package have ever been seen, the package will be unknown
+                    //try to load a type, and then try to recognize the package again:
+                    elements.getTypeElement(binaryName);
+                    pack = elements.getPackageElement(binaryName.substring(0, nextDot));
+                }
+                if (pack != null)
+                    packs.add(pack);
+            }
+        } catch (IOException ex) {
+            //TODO: should log?
+        }
+    }
+    //where:
+        private final Set<JavaFileObject.Kind> fileKinds = EnumSet.of(JavaFileObject.Kind.CLASS);
+
+    private Element createArrayLengthSymbol(AnalyzeTask at, TypeMirror site) {
+        Name length = Names.instance(at.getContext()).length;
+        Type intType = Symtab.instance(at.getContext()).intType;
+
+        return new VarSymbol(Flags.PUBLIC | Flags.FINAL, length, intType, ((Type) site).tsym);
+    }
+
+    private Element createDotClassSymbol(AnalyzeTask at, TypeMirror site) {
+        Name _class = Names.instance(at.getContext())._class;
+        Type classType = Symtab.instance(at.getContext()).classType;
+        Type erasedSite = (Type)at.getTypes().erasure(site);
+        classType = new ClassType(classType.getEnclosingType(), com.sun.tools.javac.util.List.of(erasedSite), classType.asElement());
+
+        return new VarSymbol(Flags.PUBLIC | Flags.STATIC | Flags.FINAL, _class, classType, erasedSite.tsym);
+    }
+
+    private Iterable<? extends Element> scopeContent(AnalyzeTask at, Scope scope, Function<Element, Iterable<? extends Element>> elementConvertor) {
+        Iterable<Scope> scopeIterable = () -> new Iterator<Scope>() {
+            private Scope currentScope = scope;
+            @Override
+            public boolean hasNext() {
+                return currentScope != null;
+            }
+            @Override
+            public Scope next() {
+                if (!hasNext())
+                    throw new NoSuchElementException();
+                try {
+                    return currentScope;
+                } finally {
+                    currentScope = currentScope.getEnclosingScope();
+                }
+            }
+        };
+        @SuppressWarnings("unchecked")
+        List<Element> result = Util.stream(scopeIterable)
+                             .flatMap(s -> Util.stream((Iterable<Element>)s.getLocalElements()))
+                             .flatMap(el -> Util.stream((Iterable<Element>)elementConvertor.apply(el)))
+                             .collect(toCollection(ArrayList :: new));
+        result.addAll(listPackages(at, ""));
+        return result;
+    }
+
+    @SuppressWarnings("fallthrough")
+    private Iterable<TypeMirror> findTargetType(AnalyzeTask at, TreePath forPath) {
+        if (forPath.getParentPath() == null)
+            return null;
+
+        Tree current = forPath.getLeaf();
+
+        switch (forPath.getParentPath().getLeaf().getKind()) {
+            case ASSIGNMENT: {
+                AssignmentTree tree = (AssignmentTree) forPath.getParentPath().getLeaf();
+                if (tree.getExpression() == current)
+                    return Collections.singletonList(at.trees().getTypeMirror(new TreePath(forPath.getParentPath(), tree.getVariable())));
+                break;
+            }
+            case VARIABLE: {
+                VariableTree tree = (VariableTree) forPath.getParentPath().getLeaf();
+                if (tree.getInitializer()== current)
+                    return Collections.singletonList(at.trees().getTypeMirror(forPath.getParentPath()));
+                break;
+            }
+            case ERRONEOUS:
+                return findTargetType(at, forPath.getParentPath());
+            case NEW_CLASS: {
+                NewClassTree nct = (NewClassTree) forPath.getParentPath().getLeaf();
+                List<TypeMirror> actuals = computeActualInvocationTypes(at, nct.getArguments(), forPath);
+
+                if (actuals != null) {
+                    Iterable<Pair<ExecutableElement, ExecutableType>> candidateConstructors = newClassCandidates(at, forPath.getParentPath());
+
+                    return computeSmartTypesForExecutableType(at, candidateConstructors, actuals);
+                } else {
+                    return findTargetType(at, forPath.getParentPath());
+                }
+            }
+            case METHOD:
+                if (!isThrowsClause(forPath)) {
+                    break;
+                }
+                // fall through
+            case THROW:
+                return Collections.singletonList(at.getElements().getTypeElement("java.lang.Throwable").asType());
+            case METHOD_INVOCATION: {
+                MethodInvocationTree mit = (MethodInvocationTree) forPath.getParentPath().getLeaf();
+                List<TypeMirror> actuals = computeActualInvocationTypes(at, mit.getArguments(), forPath);
+
+                if (actuals == null)
+                    return null;
+
+                Iterable<Pair<ExecutableElement, ExecutableType>> candidateMethods = methodCandidates(at, forPath.getParentPath());
+
+                return computeSmartTypesForExecutableType(at, candidateMethods, actuals);
+            }
+        }
+
+        return null;
+    }
+
+    private List<TypeMirror> computeActualInvocationTypes(AnalyzeTask at, List<? extends ExpressionTree> arguments, TreePath currentArgument) {
+        if (currentArgument == null)
+            return null;
+
+        int paramIndex = arguments.indexOf(currentArgument.getLeaf());
+
+        if (paramIndex == (-1))
+            return null;
+
+        List<TypeMirror> actuals = new ArrayList<>();
+
+        for (ExpressionTree arg : arguments.subList(0, paramIndex)) {
+            actuals.add(at.trees().getTypeMirror(new TreePath(currentArgument.getParentPath(), arg)));
+        }
+
+        return actuals;
+    }
+
+    private List<Pair<ExecutableElement, ExecutableType>> filterExecutableTypesByArguments(AnalyzeTask at, Iterable<Pair<ExecutableElement, ExecutableType>> candidateMethods, List<TypeMirror> precedingActualTypes) {
+        List<Pair<ExecutableElement, ExecutableType>> candidate = new ArrayList<>();
+        int paramIndex = precedingActualTypes.size();
+
+        OUTER:
+        for (Pair<ExecutableElement, ExecutableType> method : candidateMethods) {
+            boolean varargInvocation = paramIndex >= method.snd.getParameterTypes().size();
+
+            for (int i = 0; i < paramIndex; i++) {
+                TypeMirror actual = precedingActualTypes.get(i);
+
+                if (this.parameterType(method.fst, method.snd, i, !varargInvocation)
+                        .noneMatch(formal -> at.getTypes().isAssignable(actual, formal))) {
+                    continue OUTER;
+                }
+            }
+            candidate.add(method);
+        }
+
+        return candidate;
+    }
+
+    private Stream<TypeMirror> parameterType(ExecutableElement method, ExecutableType methodType, int paramIndex, boolean allowVarArgsArray) {
+        int paramCount = methodType.getParameterTypes().size();
+        if (paramIndex >= paramCount && !method.isVarArgs())
+            return Stream.empty();
+        if (paramIndex < paramCount - 1 || !method.isVarArgs())
+            return Stream.of(methodType.getParameterTypes().get(paramIndex));
+        TypeMirror varargType = methodType.getParameterTypes().get(paramCount - 1);
+        TypeMirror elemenType = ((ArrayType) varargType).getComponentType();
+        if (paramIndex >= paramCount || !allowVarArgsArray)
+            return Stream.of(elemenType);
+        return Stream.of(varargType, elemenType);
+    }
+
+    private List<TypeMirror> computeSmartTypesForExecutableType(AnalyzeTask at, Iterable<Pair<ExecutableElement, ExecutableType>> candidateMethods, List<TypeMirror> precedingActualTypes) {
+        List<TypeMirror> candidate = new ArrayList<>();
+        int paramIndex = precedingActualTypes.size();
+
+        this.filterExecutableTypesByArguments(at, candidateMethods, precedingActualTypes)
+            .stream()
+            .flatMap(method -> parameterType(method.fst, method.snd, paramIndex, true))
+            .forEach(candidate::add);
+
+        return candidate;
+    }
+
+
+    private TypeMirror resultTypeOf(Element el) {
+        //TODO: should reflect the type of site!
+        switch (el.getKind()) {
+            case METHOD:
+                return ((ExecutableElement) el).getReturnType();
+            case CONSTRUCTOR:
+            case INSTANCE_INIT: case STATIC_INIT: //TODO: should be filtered out
+                return el.getEnclosingElement().asType();
+            default:
+                return el.asType();
+        }
+    }
+
+    private void addScopeElements(AnalyzeTask at, Scope scope, Function<Element, Iterable<? extends Element>> elementConvertor, Predicate<Element> filter, Predicate<Element> smartFilter, List<Suggestion> result) {
+        addElements(scopeContent(at, scope, elementConvertor), filter, smartFilter, result);
+    }
+
+    private Iterable<Pair<ExecutableElement, ExecutableType>> methodCandidates(AnalyzeTask at, TreePath invocation) {
+        MethodInvocationTree mit = (MethodInvocationTree) invocation.getLeaf();
+        ExpressionTree select = mit.getMethodSelect();
+        List<Pair<ExecutableElement, ExecutableType>> result = new ArrayList<>();
+        Predicate<Element> accessibility = createAccessibilityFilter(at, invocation);
+
+        switch (select.getKind()) {
+            case MEMBER_SELECT:
+                MemberSelectTree mst = (MemberSelectTree) select;
+                TreePath tp = new TreePath(new TreePath(invocation, select), mst.getExpression());
+                TypeMirror site = at.trees().getTypeMirror(tp);
+
+                if (site == null || site.getKind() != TypeKind.DECLARED)
+                    break;
+
+                Element siteEl = at.getTypes().asElement(site);
+
+                if (siteEl == null)
+                    break;
+
+                if (isStaticContext(at, tp)) {
+                    accessibility = accessibility.and(STATIC_ONLY);
+                }
+
+                for (ExecutableElement ee : ElementFilter.methodsIn(membersOf(at, siteEl.asType(), false))) {
+                    if (ee.getSimpleName().contentEquals(mst.getIdentifier())) {
+                        if (accessibility.test(ee)) {
+                            result.add(Pair.of(ee, (ExecutableType) at.getTypes().asMemberOf((DeclaredType) site, ee)));
+                        }
+                    }
+                }
+                break;
+            case IDENTIFIER:
+                IdentifierTree it = (IdentifierTree) select;
+                for (ExecutableElement ee : ElementFilter.methodsIn(scopeContent(at, at.trees().getScope(invocation), IDENTITY))) {
+                    if (ee.getSimpleName().contentEquals(it.getName())) {
+                        if (accessibility.test(ee)) {
+                            result.add(Pair.of(ee, (ExecutableType) ee.asType())); //XXX: proper site
+                        }
+                    }
+                }
+                break;
+            default:
+                break;
+        }
+
+        return result;
+    }
+
+    private Iterable<Pair<ExecutableElement, ExecutableType>> newClassCandidates(AnalyzeTask at, TreePath newClassPath) {
+        NewClassTree nct = (NewClassTree) newClassPath.getLeaf();
+        Element type = at.trees().getElement(new TreePath(newClassPath.getParentPath(), nct.getIdentifier()));
+        TypeMirror targetType = at.trees().getTypeMirror(newClassPath);
+        if (targetType == null || targetType.getKind() != TypeKind.DECLARED) {
+            Iterable<TypeMirror> targetTypes = findTargetType(at, newClassPath);
+            if (targetTypes == null)
+                targetTypes = Collections.emptyList();
+            targetType =
+                    StreamSupport.stream(targetTypes.spliterator(), false)
+                                 .filter(t -> at.getTypes().asElement(t) == type)
+                                 .findAny()
+                                 .orElse(at.getTypes().erasure(type.asType()));
+        }
+        List<Pair<ExecutableElement, ExecutableType>> candidateConstructors = new ArrayList<>();
+        Predicate<Element> accessibility = createAccessibilityFilter(at, newClassPath);
+
+        if (targetType != null &&
+            targetType.getKind() == TypeKind.DECLARED &&
+            type != null &&
+            (type.getKind().isClass() || type.getKind().isInterface())) {
+            for (ExecutableElement constr : ElementFilter.constructorsIn(type.getEnclosedElements())) {
+                if (accessibility.test(constr)) {
+                    ExecutableType constrType =
+                            (ExecutableType) at.getTypes().asMemberOf((DeclaredType) targetType, constr);
+                    candidateConstructors.add(Pair.of(constr, constrType));
+                }
+            }
+        }
+
+        return candidateConstructors;
+    }
+
+    @Override
+    public String documentation(String code, int cursor) {
+        code = code.substring(0, cursor);
+        if (code.trim().isEmpty()) { //TODO: comment handling
+            code += ";";
+        }
+
+        if (guessKind(code) == Kind.IMPORT)
+            return null;
+
+        OuterWrap codeWrap = wrapInClass(Wrap.methodWrap(code));
+        AnalyzeTask at = proc.taskFactory.new AnalyzeTask(codeWrap);
+        SourcePositions sp = at.trees().getSourcePositions();
+        CompilationUnitTree topLevel = at.cuTree();
+        TreePath tp = pathFor(topLevel, sp, codeWrap.snippetIndexToWrapIndex(cursor));
+
+        if (tp == null)
+            return null;
+
+        TreePath prevPath = null;
+        while (tp != null && tp.getLeaf().getKind() != Kind.METHOD_INVOCATION && tp.getLeaf().getKind() != Kind.NEW_CLASS) {
+            prevPath = tp;
+            tp = tp.getParentPath();
+        }
+
+        if (tp == null)
+            return null;
+
+        Iterable<Pair<ExecutableElement, ExecutableType>> candidates;
+        List<? extends ExpressionTree> arguments;
+
+        if (tp.getLeaf().getKind() == Kind.METHOD_INVOCATION) {
+            MethodInvocationTree mit = (MethodInvocationTree) tp.getLeaf();
+            candidates = methodCandidates(at, tp);
+            arguments = mit.getArguments();
+        } else {
+            NewClassTree nct = (NewClassTree) tp.getLeaf();
+            candidates = newClassCandidates(at, tp);
+            arguments = nct.getArguments();
+        }
+
+        if (!isEmptyArgumentsContext(arguments)) {
+            List<TypeMirror> actuals = computeActualInvocationTypes(at, arguments, prevPath);
+            List<TypeMirror> fullActuals = actuals != null ? actuals : Collections.emptyList();
+
+            candidates =
+                    this.filterExecutableTypesByArguments(at, candidates, fullActuals)
+                        .stream()
+                        .filter(method -> parameterType(method.fst, method.snd, fullActuals.size(), true).findAny().isPresent())
+                        .collect(Collectors.toList());
+        }
+
+        return Util.stream(candidates)
+                .map(method -> Util.expunge(element2String(method.fst)))
+                .collect(joining("\n"));
+    }
+
+    private boolean isEmptyArgumentsContext(List<? extends ExpressionTree> arguments) {
+        if (arguments.size() == 1) {
+            Tree firstArgument = arguments.get(0);
+            return firstArgument.getKind() == Kind.ERRONEOUS;
+        }
+        return false;
+    }
+
+    private String element2String(Element el) {
+        switch (el.getKind()) {
+            case ANNOTATION_TYPE: case CLASS: case ENUM: case INTERFACE:
+                return ((TypeElement) el).getQualifiedName().toString();
+            case FIELD:
+                return element2String(el.getEnclosingElement()) + "." + el.getSimpleName() + ":" + el.asType();
+            case ENUM_CONSTANT:
+                return element2String(el.getEnclosingElement()) + "." + el.getSimpleName();
+            case EXCEPTION_PARAMETER: case LOCAL_VARIABLE: case PARAMETER: case RESOURCE_VARIABLE:
+                return el.getSimpleName() + ":" + el.asType();
+            case CONSTRUCTOR: case METHOD:
+                StringBuilder header = new StringBuilder();
+                header.append(element2String(el.getEnclosingElement()));
+                if (el.getKind() == ElementKind.METHOD) {
+                    header.append(".");
+                    header.append(el.getSimpleName());
+                }
+                header.append("(");
+                String sep = "";
+                ExecutableElement method = (ExecutableElement) el;
+                for (Iterator<? extends VariableElement> i = method.getParameters().iterator(); i.hasNext();) {
+                    VariableElement p = i.next();
+                    header.append(sep);
+                    if (!i.hasNext() && method.isVarArgs()) {
+                        header.append(unwrapArrayType(p.asType()));
+                        header.append("...");
+
+                    } else {
+                        header.append(p.asType());
+                    }
+                    header.append(" ");
+                    header.append(p.getSimpleName());
+                    sep = ", ";
+                }
+                header.append(")");
+                return header.toString();
+           default:
+                return el.toString();
+        }
+    }
+    private TypeMirror unwrapArrayType(TypeMirror arrayType) {
+        if (arrayType.getKind() == TypeKind.ARRAY) {
+            return ((ArrayType)arrayType).getComponentType();
+        }
+        return arrayType;
+    }
+}