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Java example source code file (DPrinter.java)

This example Java source code file (DPrinter.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

decl_in_progress, decl_not_started, details, dprinter, file, handler, jctree, list, object, override, reflection, string, symbol, treescanner, util, void

The DPrinter.java Java example source code

/*
 * Copyright (c) 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.
 *
 * 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.
 */

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.EnumSet;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;

import javax.lang.model.element.Name;
import javax.lang.model.element.TypeElement;
import javax.tools.FileObject;
import javax.tools.JavaCompiler;
import javax.tools.JavaFileObject;
import javax.tools.StandardJavaFileManager;
import javax.tools.StandardLocation;
import javax.tools.ToolProvider;

import com.sun.source.util.JavacTask;
import com.sun.source.util.TaskEvent;
import com.sun.source.util.TaskListener;
import com.sun.source.util.Trees;
import com.sun.tools.javac.api.JavacTrees;
import com.sun.tools.javac.code.SymbolMetadata;
import com.sun.tools.javac.code.Attribute;
import com.sun.tools.javac.code.Flags;
import com.sun.tools.javac.code.Kinds;
import com.sun.tools.javac.code.Printer;
import com.sun.tools.javac.code.Scope;
import com.sun.tools.javac.code.Scope.CompoundScope;
import com.sun.tools.javac.code.Symbol;
import com.sun.tools.javac.code.Symbol.*;
import com.sun.tools.javac.code.Type;
import com.sun.tools.javac.code.Type.*;
import com.sun.tools.javac.code.TypeTag;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.tree.JCTree.*;
import com.sun.tools.javac.tree.Pretty;
import com.sun.tools.javac.tree.TreeInfo;
import com.sun.tools.javac.tree.TreeScanner;
import com.sun.tools.javac.util.Assert;
import com.sun.tools.javac.util.Context;
import com.sun.tools.javac.util.Log;


/**
 * Debug printer for javac internals, for when toString() just isn't enough.
 *
 * <p>
 * The printer provides an API to generate structured views of javac objects,
 * such as AST nodes, symbol, types and annotations. Various aspects of the
 * output can be configured, such as whether to show nulls, empty lists, or
 * a compressed representation of the source code. Visitors are used to walk
 * object hierarchies, and can be replaced with custom visitors if the default
 * visitors are not flexible enough.
 *
 * <p>
 * In general, nodes are printed with an initial line identifying the node
 * followed by indented lines for the child nodes. Currently, graphs are
 * represented by printing a spanning subtree.
 *
 * <p>
 * The printer can be accessed via a simple command-line utility,
 * which makes it easy to see the internal representation of source code,
 * such as simple test programs, during the compilation pipeline.
 *
 *  <p>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 */

public class DPrinter {
    protected final PrintWriter out;
    protected final Trees trees;
    protected Printer printer;
    protected boolean showEmptyItems = true;
    protected boolean showNulls = true;
    protected boolean showPositions = false;
    protected boolean showSrc;
    protected boolean showTreeSymbols;
    protected boolean showTreeTypes;
    protected int maxSrcLength = 32;
    protected Locale locale = Locale.getDefault();
    protected static final String NULL = "#null";

    // <editor-fold defaultstate="collapsed" desc="Configuration">

    public static DPrinter instance(Context context) {
        DPrinter dp = context.get(DPrinter.class);
        if (dp == null) {
            dp = new DPrinter(context);
        }
        return dp;

    }

    protected DPrinter(Context context) {
        context.put(DPrinter.class, this);
        out = context.get(Log.outKey);
        trees = JavacTrees.instance(context);
    }

    public DPrinter(PrintWriter out, Trees trees) {
        this.out = out;
        this.trees = trees;
    }

    public DPrinter emptyItems(boolean showEmptyItems) {
        this.showEmptyItems = showEmptyItems;
        return this;
    }

    public DPrinter nulls(boolean showNulls) {
        this.showNulls = showNulls;
        return this;
    }

    public DPrinter positions(boolean showPositions) {
        this.showPositions = showPositions;
        return this;
    }

    public DPrinter source(boolean showSrc) {
        this.showSrc = showSrc;
        return this;
    }

    public DPrinter source(int maxSrcLength) {
        this.showSrc = true;
        this.maxSrcLength = maxSrcLength;
        return this;
    }

    public DPrinter treeSymbols(boolean showTreeSymbols) {
        this.showTreeSymbols = showTreeSymbols;
        return this;
    }

    public DPrinter treeTypes(boolean showTreeTypes) {
        this.showTreeTypes = showTreeTypes;
        return this;
    }

    public DPrinter typeSymbolPrinter(Printer p) {
        printer = p;
        return this;
    }

    // </editor-fold>

    // <editor-fold defaultstate="collapsed" desc="Printing">

    protected enum Details {
        /** A one-line non-recursive summary */
        SUMMARY,
        /** Multi-line, possibly recursive. */
        FULL
    };

    public void printAnnotations(String label, SymbolMetadata annotations) {
        printAnnotations(label, annotations, Details.FULL);
    }

    protected void printAnnotations(String label, SymbolMetadata annotations, Details details) {
        if (annotations == null) {
            printNull(label);
        } else {
            // no SUMMARY format currently available to use

            // use reflection to get at private fields
            Object DECL_NOT_STARTED = getField(null, SymbolMetadata.class, "DECL_NOT_STARTED");
            Object DECL_IN_PROGRESS = getField(null, SymbolMetadata.class, "DECL_IN_PROGRESS");
            Object attributes = getField(annotations, SymbolMetadata.class, "attributes");
            Object type_attributes = getField(annotations, SymbolMetadata.class, "type_attributes");

            if (!showEmptyItems) {
                if (attributes instanceof List && ((List) attributes).isEmpty()
                        && attributes != DECL_NOT_STARTED
                        && attributes != DECL_IN_PROGRESS
                        && type_attributes instanceof List && ((List) type_attributes).isEmpty())
                    return;
            }

            printString(label, hashString(annotations));

            indent(+1);
            if (attributes == DECL_NOT_STARTED)
                printString("attributes", "DECL_NOT_STARTED");
            else if (attributes == DECL_IN_PROGRESS)
                printString("attributes", "DECL_IN_PROGRESS");
            else if (attributes instanceof List)
                printList("attributes", (List) attributes);
            else
                printObject("attributes", attributes, Details.SUMMARY);

            if (attributes instanceof List)
                printList("type_attributes", (List) type_attributes);
            else
                printObject("type_attributes", type_attributes, Details.SUMMARY);
            indent(-1);
        }
    }

    public void printAttribute(String label, Attribute attr) {
        if (attr == null) {
            printNull(label);
        } else {
            printString(label, attr.getClass().getSimpleName());

            indent(+1);
            attr.accept(attrVisitor);
            indent(-1);
        }
    }

    public void printFileObject(String label, FileObject fo) {
        if (fo == null) {
            printNull(label);
        } else {
            printString(label, fo.getName());
        }
    }

    protected <T> void printImplClass(T item, Class stdImplClass) {
        if (item.getClass() != stdImplClass)
            printString("impl", item.getClass().getName());
    }

    public void printInt(String label, int i) {
        printString(label, String.valueOf(i));
    }

    public void printList(String label, List<?> list) {
        if (list == null) {
             printNull(label);
        } else if (!list.isEmpty() || showEmptyItems) {
            printString(label, "[" + list.size() + "]");

            indent(+1);
            int i = 0;
            for (Object item: list) {
                printObject(String.valueOf(i++), item, Details.FULL);
            }
            indent(-1);
        }
    }

    public void printName(String label, Name name) {
        if (name == null) {
            printNull(label);
        } else {
            printString(label, name.toString());
        }
    }

    public void printNull(String label) {
        if (showNulls)
            printString(label, NULL);
    }

    protected void printObject(String label, Object item, Details details) {
        if (item == null) {
            printNull(label);
        } else if (item instanceof Attribute) {
            printAttribute(label, (Attribute) item);
        } else if (item instanceof Symbol) {
            printSymbol(label, (Symbol) item, details);
        } else if (item instanceof Type) {
            printType(label, (Type) item, details);
        } else if (item instanceof JCTree) {
            printTree(label, (JCTree) item);
        } else if (item instanceof List) {
            printList(label, (List) item);
        } else if (item instanceof Name) {
            printName(label, (Name) item);
        } else {
            printString(label, String.valueOf(item));
        }
    }

    public void printScope(String label, Scope scope) {
        printScope(label, scope, Details.FULL);
    }

    public void printScope(String label, Scope scope, Details details) {
        if (scope == null) {
            printNull(label);
        } else {
            switch (details) {
                case SUMMARY: {
                    indent();
                    out.print(label);
                    out.print(": [");
                    String sep = "";
                    for (Symbol sym: scope.getElements()) {
                        out.print(sep);
                        out.print(sym.name);
                        sep = ",";
                    }
                    out.println("]");
                    break;
                }

                case FULL: {
                    indent();
                    out.println(label);

                    indent(+1);
                    printImplClass(scope, Scope.class);
                    printSymbol("owner", scope.owner, Details.SUMMARY);
                    printScope("next", scope.next, Details.SUMMARY);
                    printObject("shared", getField(scope, Scope.class, "shared"), Details.SUMMARY);
                    if (scope instanceof CompoundScope) {
                        printObject("subScopes",
                                getField(scope, CompoundScope.class, "subScopes"),
                                Details.FULL);
                    } else {
                        for (Symbol sym : scope.getElements()) {
                            printSymbol(sym.name.toString(), sym, Details.SUMMARY);
                        }
                    }
                    indent(-1);
                    break;
                }
            }
        }
    }

    public void printSource(String label, JCTree tree) {
        printString(label, Pretty.toSimpleString(tree, maxSrcLength));
    }

    public void printString(String label, String text) {
        indent();
        out.print(label);
        out.print(": ");
        out.print(text);
        out.println();
    }

    public void printSymbol(String label, Symbol symbol) {
        printSymbol(label, symbol, Details.FULL);
    }

    protected void printSymbol(String label, Symbol sym, Details details) {
        if (sym == null) {
            printNull(label);
        } else {
            switch (details) {
            case SUMMARY:
                printString(label, toString(sym));
                break;

            case FULL:
                indent();
                out.print(label);
                out.println(": " +
                        info(sym.getClass(),
                            String.format("0x%x--%s", sym.kind, Kinds.kindName(sym)),
                            sym.getKind())
                        + " " + sym.name
                        + " " + hashString(sym));

                indent(+1);
                if (showSrc) {
                    JCTree tree = (JCTree) trees.getTree(sym);
                    if (tree != null)
                        printSource("src", tree);
                }
                printString("flags", String.format("0x%x--%s",
                        sym.flags_field, Flags.toString(sym.flags_field)));
                printObject("completer", sym.completer, Details.SUMMARY); // what if too long?
                printSymbol("owner", sym.owner, Details.SUMMARY);
                printType("type", sym.type, Details.SUMMARY);
                printType("erasure", sym.erasure_field, Details.SUMMARY);
                sym.accept(symVisitor, null);
                printAnnotations("annotations", sym.getAnnotations(), Details.SUMMARY);
                indent(-1);
            }
        }
    }

    protected String toString(Symbol sym) {
        return (printer != null) ? printer.visit(sym, locale) : String.valueOf(sym);
    }

    protected void printTree(String label, JCTree tree) {
        if (tree == null) {
            printNull(label);
        } else {
            indent();
            String ext;
            try {
                ext = tree.getKind().name();
            } catch (Throwable t) {
                ext = "n/a";
            }
            out.print(label + ": " + info(tree.getClass(), tree.getTag(), ext));
            if (showPositions) {
                // We can always get start position, but to get end position
                // and/or line+offset, we would need a JCCompilationUnit
                out.print(" pos:" + tree.pos);
            }
            if (showTreeTypes && tree.type != null)
                out.print(" type:" + toString(tree.type));
            Symbol sym;
            if (showTreeSymbols && (sym = TreeInfo.symbolFor(tree)) != null)
                out.print(" sym:" + toString(sym));
            out.println();

            indent(+1);
            if (showSrc) {
                indent();
                out.println("src: " + Pretty.toSimpleString(tree, maxSrcLength));
            }
            tree.accept(treeVisitor);
            indent(-1);
        }
    }

    public void printType(String label, Type type) {
        printType(label, type, Details.FULL);
    }

    protected void printType(String label, Type type, Details details) {
        if (type == null)
            printNull(label);
        else {
            switch (details) {
                case SUMMARY:
                    printString(label, toString(type));
                    break;

                case FULL:
                    indent();
                    out.print(label);
                    out.println(": " + info(type.getClass(), type.getTag(), type.getKind())
                            + " " + hashString(type));

                    indent(+1);
                    printSymbol("tsym", type.tsym, Details.SUMMARY);
                    printObject("constValue", type.constValue(), Details.SUMMARY);
                    printObject("annotations", type.getAnnotationMirrors(), Details.SUMMARY);
                    type.accept(typeVisitor, null);
                    indent(-1);
            }
        }
    }

    protected String toString(Type type) {
        return (printer != null) ? printer.visit(type, locale) : String.valueOf(type);
    }

    protected String hashString(Object obj) {
        return String.format("#%x", obj.hashCode());
    }

    protected String info(Class<?> clazz, Object internal, Object external) {
        return String.format("%s,%s,%s", clazz.getSimpleName(), internal, external);
    }

    private int indent = 0;

    protected void indent() {
        for (int i = 0; i < indent; i++) {
            out.print("  ");
        }
    }

    protected void indent(int n) {
        indent += n;
    }

    protected Object getField(Object o, Class<?> clazz, String name) {
        try {
            Field f = clazz.getDeclaredField(name);
            boolean prev = f.isAccessible();
            f.setAccessible(true);
            try {
                return f.get(o);
            } finally {
                f.setAccessible(prev);
            }
        } catch (ReflectiveOperationException e) {
            return e;
        } catch (SecurityException e) {
            return e;
        }
    }

    // </editor-fold>

    // <editor-fold defaultstate="collapsed" desc="JCTree visitor methods">

    protected JCTree.Visitor treeVisitor = new TreeVisitor();

    /**
     * Default visitor class for JCTree (AST) objects.
     */
    public class TreeVisitor extends JCTree.Visitor {
        @Override
        public void visitTopLevel(JCCompilationUnit tree) {
            printList("packageAnnotations", tree.packageAnnotations);
            printTree("pid", tree.pid);
            printList("defs", tree.defs);
        }

        @Override
        public void visitImport(JCImport tree) {
            printTree("qualid", tree.qualid);
        }

        @Override
        public void visitClassDef(JCClassDecl tree) {
            printName("name", tree.name);
            printTree("mods", tree.mods);
            printList("typarams", tree.typarams);
            printTree("extending", tree.extending);
            printList("implementing", tree.implementing);
            printList("defs", tree.defs);
        }

        @Override
        public void visitMethodDef(JCMethodDecl tree) {
            printName("name", tree.name);
            printTree("mods", tree.mods);
            printTree("restype", tree.restype);
            printList("typarams", tree.typarams);
            printTree("recvparam", tree.recvparam);
            printList("params", tree.params);
            printList("thrown", tree.thrown);
            printTree("defaultValue", tree.defaultValue);
            printTree("body", tree.body);
        }

        @Override
        public void visitVarDef(JCVariableDecl tree) {
            printName("name", tree.name);
            printTree("mods", tree.mods);
            printTree("vartype", tree.vartype);
            printTree("init", tree.init);
        }

        @Override
        public void visitSkip(JCSkip tree) {
        }

        @Override
        public void visitBlock(JCBlock tree) {
            printList("stats", tree.stats);
        }

        @Override
        public void visitDoLoop(JCDoWhileLoop tree) {
            printTree("body", tree.body);
            printTree("cond", tree.cond);
        }

        @Override
        public void visitWhileLoop(JCWhileLoop tree) {
            printTree("cond", tree.cond);
            printTree("body", tree.body);
        }

        @Override
        public void visitForLoop(JCForLoop tree) {
            printList("init", tree.init);
            printTree("cond", tree.cond);
            printList("step", tree.step);
            printTree("body", tree.body);
        }

        @Override
        public void visitForeachLoop(JCEnhancedForLoop tree) {
            printTree("var", tree.var);
            printTree("expr", tree.expr);
            printTree("body", tree.body);
        }

        @Override
        public void visitLabelled(JCLabeledStatement tree) {
            printTree("body", tree.body);
        }

        @Override
        public void visitSwitch(JCSwitch tree) {
            printTree("selector", tree.selector);
            printList("cases", tree.cases);
        }

        @Override
        public void visitCase(JCCase tree) {
            printTree("pat", tree.pat);
            printList("stats", tree.stats);
        }

        @Override
        public void visitSynchronized(JCSynchronized tree) {
            printTree("lock", tree.lock);
            printTree("body", tree.body);
        }

        @Override
        public void visitTry(JCTry tree) {
            printList("resources", tree.resources);
            printTree("body", tree.body);
            printList("catchers", tree.catchers);
            printTree("finalizer", tree.finalizer);
        }

        @Override
        public void visitCatch(JCCatch tree) {
            printTree("param", tree.param);
            printTree("body", tree.body);
        }

        @Override
        public void visitConditional(JCConditional tree) {
            printTree("cond", tree.cond);
            printTree("truepart", tree.truepart);
            printTree("falsepart", tree.falsepart);
        }

        @Override
        public void visitIf(JCIf tree) {
            printTree("cond", tree.cond);
            printTree("thenpart", tree.thenpart);
            printTree("elsepart", tree.elsepart);
        }

        @Override
        public void visitExec(JCExpressionStatement tree) {
            printTree("expr", tree.expr);
        }

        @Override
        public void visitBreak(JCBreak tree) {
            printName("label", tree.label);
        }

        @Override
        public void visitContinue(JCContinue tree) {
            printName("label", tree.label);
        }

        @Override
        public void visitReturn(JCReturn tree) {
            printTree("expr", tree.expr);
        }

        @Override
        public void visitThrow(JCThrow tree) {
            printTree("expr", tree.expr);
        }

        @Override
        public void visitAssert(JCAssert tree) {
            printTree("cond", tree.cond);
            printTree("detail", tree.detail);
        }

        @Override
        public void visitApply(JCMethodInvocation tree) {
            printList("typeargs", tree.typeargs);
            printTree("meth", tree.meth);
            printList("args", tree.args);
        }

        @Override
        public void visitNewClass(JCNewClass tree) {
            printTree("encl", tree.encl);
            printList("typeargs", tree.typeargs);
            printTree("clazz", tree.clazz);
            printList("args", tree.args);
            printTree("def", tree.def);
        }

        @Override
        public void visitNewArray(JCNewArray tree) {
            printList("annotations", tree.annotations);
            printTree("elemtype", tree.elemtype);
            printList("dims", tree.dims);
            printList("dimAnnotations", tree.dimAnnotations);
            printList("elems", tree.elems);
        }

        @Override
        public void visitLambda(JCLambda tree) {
            printTree("body", tree.body);
            printList("params", tree.params);
        }

        @Override
        public void visitParens(JCParens tree) {
            printTree("expr", tree.expr);
        }

        @Override
        public void visitAssign(JCAssign tree) {
            printTree("lhs", tree.lhs);
            printTree("rhs", tree.rhs);
        }

        @Override
        public void visitAssignop(JCAssignOp tree) {
            printTree("lhs", tree.lhs);
            printTree("rhs", tree.rhs);
        }

        @Override
        public void visitUnary(JCUnary tree) {
            printTree("arg", tree.arg);
        }

        @Override
        public void visitBinary(JCBinary tree) {
            printTree("lhs", tree.lhs);
            printTree("rhs", tree.rhs);
        }

        @Override
        public void visitTypeCast(JCTypeCast tree) {
            printTree("clazz", tree.clazz);
            printTree("expr", tree.expr);
        }

        @Override
        public void visitTypeTest(JCInstanceOf tree) {
            printTree("expr", tree.expr);
            printTree("clazz", tree.clazz);
        }

        @Override
        public void visitIndexed(JCArrayAccess tree) {
            printTree("indexed", tree.indexed);
            printTree("index", tree.index);
        }

        @Override
        public void visitSelect(JCFieldAccess tree) {
            printTree("selected", tree.selected);
        }

        @Override
        public void visitReference(JCMemberReference tree) {
            printTree("expr", tree.expr);
            printList("typeargs", tree.typeargs);
        }

        @Override
        public void visitIdent(JCIdent tree) {
            printName("name", tree.name);
        }

        @Override
        public void visitLiteral(JCLiteral tree) {
            printString("value", Pretty.toSimpleString(tree, 32));
        }

        @Override
        public void visitTypeIdent(JCPrimitiveTypeTree tree) {
            printString("typetag", tree.typetag.name());
        }

        @Override
        public void visitTypeArray(JCArrayTypeTree tree) {
            printTree("elemtype", tree.elemtype);
        }

        @Override
        public void visitTypeApply(JCTypeApply tree) {
            printTree("clazz", tree.clazz);
            printList("arguments", tree.arguments);
        }

        @Override
        public void visitTypeUnion(JCTypeUnion tree) {
            printList("alternatives", tree.alternatives);
        }

        @Override
        public void visitTypeIntersection(JCTypeIntersection tree) {
            printList("bounds", tree.bounds);
        }

        @Override
        public void visitTypeParameter(JCTypeParameter tree) {
            printName("name", tree.name);
            printList("annotations", tree.annotations);
            printList("bounds", tree.bounds);
        }

        @Override
        public void visitWildcard(JCWildcard tree) {
            printTree("kind", tree.kind);
            printTree("inner", tree.inner);
        }

        @Override
        public void visitTypeBoundKind(TypeBoundKind tree) {
            printString("kind", tree.kind.name());
        }

        @Override
        public void visitModifiers(JCModifiers tree) {
            printList("annotations", tree.annotations);
            printString("flags", String.valueOf(Flags.asFlagSet(tree.flags)));
        }

        @Override
        public void visitAnnotation(JCAnnotation tree) {
            printTree("annotationType", tree.annotationType);
            printList("args", tree.args);
        }

        @Override
        public void visitAnnotatedType(JCAnnotatedType tree) {
            printList("annotations", tree.annotations);
            printTree("underlyingType", tree.underlyingType);
        }

        @Override
        public void visitErroneous(JCErroneous tree) {
            printList("errs", tree.errs);
        }

        @Override
        public void visitLetExpr(LetExpr tree) {
            printList("defs", tree.defs);
            printTree("expr", tree.expr);
        }

        @Override
        public void visitTree(JCTree tree) {
            Assert.error();
        }
    }

    // </editor-fold>

    // <editor-fold defaultstate="collapsed" desc="Symbol visitor">

    protected Symbol.Visitor<Void,Void> symVisitor = new SymbolVisitor();

    /**
     * Default visitor class for Symbol objects.
     * Note: each visitXYZ method ends by calling the corresponding
     * visit method for its superclass.
     */
    class SymbolVisitor implements Symbol.Visitor<Void,Void> {
        @Override
        public Void visitClassSymbol(ClassSymbol sym, Void ignore) {
            printName("fullname", sym.fullname);
            printName("flatname", sym.flatname);
            printScope("members", sym.members_field);
            printFileObject("sourcefile", sym.sourcefile);
            printFileObject("classfile", sym.classfile);
            // trans-local?
            // pool?
            return visitTypeSymbol(sym, null);
        }

        @Override
        public Void visitMethodSymbol(MethodSymbol sym, Void ignore) {
            // code
            printList("params", sym.params);
            printList("savedParameterNames", sym.savedParameterNames);
            return visitSymbol(sym, null);
        }

        @Override
        public Void visitPackageSymbol(PackageSymbol sym, Void ignore) {
            printName("fullname", sym.fullname);
            printScope("members", sym.members_field);
            printSymbol("package-info", sym.package_info, Details.SUMMARY);
            return visitTypeSymbol(sym, null);
        }

        @Override
        public Void visitOperatorSymbol(OperatorSymbol sym, Void ignore) {
            printInt("opcode", sym.opcode);
            return visitMethodSymbol(sym, null);
        }

        @Override
        public Void visitVarSymbol(VarSymbol sym, Void ignore) {
            printInt("pos", sym.pos);
            printInt("adm", sym.adr);
            // data is a private field, and the standard accessors may
            // mutate it as part of lazy evaluation. Therefore, use
            // reflection to get the raw data.
            printObject("data", getField(sym, VarSymbol.class, "data"), Details.SUMMARY);
            return visitSymbol(sym, null);
        }

        @Override
        public Void visitTypeSymbol(TypeSymbol sym, Void ignore) {
            return visitSymbol(sym, null);
        }

        @Override
        public Void visitSymbol(Symbol sym, Void ignore) {
            return null;
        }
    }

    // </editor-fold>

    // <editor-fold defaultstate="collapsed" desc="Type visitor">

    protected Type.Visitor<Void,Void> typeVisitor = new TypeVisitor();

    /**
     * Default visitor class for Type objects.
     * Note: each visitXYZ method ends by calling the corresponding
     * visit method for its superclass.
     */
    public class TypeVisitor implements Type.Visitor<Void,Void> {
        public Void visitAnnotatedType(AnnotatedType type, Void ignore) {
            printList("typeAnnotations", type.getAnnotationMirrors());
            printType("underlyingType", type.unannotatedType(), Details.FULL);
            return visitType(type, null);
        }

        public Void visitArrayType(ArrayType type, Void ignore) {
            printType("elemType", type.elemtype, Details.FULL);
            return visitType(type, null);
        }

        public Void visitCapturedType(CapturedType type, Void ignore) {
            printType("wildcard", type.wildcard, Details.FULL);
            return visitTypeVar(type, null);
        }

        public Void visitClassType(ClassType type, Void ignore) {
            printType("outer", type.getEnclosingType(), Details.SUMMARY);
            printList("typarams", type.typarams_field);
            printList("allparams", type.allparams_field);
            printType("supertype", type.supertype_field, Details.SUMMARY);
            printList("interfaces", type.interfaces_field);
            printList("allinterfaces", type.all_interfaces_field);
            return visitType(type, null);
        }

        public Void visitErrorType(ErrorType type, Void ignore) {
            printType("originalType", type.getOriginalType(), Details.FULL);
            return visitClassType(type, null);
        }

        public Void visitForAll(ForAll type, Void ignore) {
            printList("tvars", type.tvars);
            return visitDelegatedType(type);
        }

        public Void visitMethodType(MethodType type, Void ignore) {
            printList("argtypes", type.argtypes);
            printType("restype", type.restype, Details.FULL);
            printList("thrown", type.thrown);
            return visitType(type, null);
        }

        public Void visitPackageType(PackageType type, Void ignore) {
            return visitType(type, null);
        }

        public Void visitTypeVar(TypeVar type, Void ignore) {
            // For TypeVars (and not subtypes), the bound should always be
            // null or bot. So, only print the bound for subtypes of TypeVar,
            // or if the bound is (erroneously) not null or bot.
            if (!type.hasTag(TypeTag.TYPEVAR)
                    || !(type.bound == null || type.bound.hasTag(TypeTag.BOT))) {
                printType("bound", type.bound, Details.FULL);
            }
            printType("lower", type.lower, Details.FULL);
            return visitType(type, null);
        }

        public Void visitUndetVar(UndetVar type, Void ignore) {
            for (UndetVar.InferenceBound ib: UndetVar.InferenceBound.values())
                printList("bounds." + ib, type.getBounds(ib));
            printInt("declaredCount", type.declaredCount);
            printType("inst", type.inst, Details.SUMMARY);
            return visitDelegatedType(type);
        }

        public Void visitWildcardType(WildcardType type, Void ignore) {
            printType("type", type.type, Details.SUMMARY);
            printString("kind", type.kind.name());
            printType("bound", type.bound, Details.SUMMARY);
            return visitType(type, null);
        }

        protected Void visitDelegatedType(DelegatedType type) {
            printType("qtype", type.qtype, Details.FULL);
            return visitType(type, null);
        }

        public Void visitType(Type type, Void ignore) {
            return null;
        }
    }

    // </editor-fold>

    // <editor-fold defaultstate="collapsed" desc="Attribute (annotations) visitor">

    protected Attribute.Visitor attrVisitor = new AttributeVisitor();

    /**
     * Default visitor class for Attribute (annotation) objects.
     */
    public class AttributeVisitor implements Attribute.Visitor {

        public void visitConstant(Attribute.Constant a) {
            printObject("value", a.value, Details.SUMMARY);
            visitAttribute(a);
        }

        public void visitClass(Attribute.Class a) {
            printObject("classType", a.classType, Details.SUMMARY);
            visitAttribute(a);
        }

        public void visitCompound(Attribute.Compound a) {
            if (a instanceof Attribute.TypeCompound) {
                Attribute.TypeCompound ta = (Attribute.TypeCompound) a;
                // consider a custom printer?
                printObject("position", ta.position, Details.SUMMARY);
            }
            printObject("synthesized", a.isSynthesized(), Details.SUMMARY);
            printList("values", a.values);
            visitAttribute(a);
        }

        public void visitArray(Attribute.Array a) {
            printList("values", Arrays.asList(a.values));
            visitAttribute(a);
        }

        public void visitEnum(Attribute.Enum a) {
            printSymbol("value", a.value, Details.SUMMARY);
            visitAttribute(a);
        }

        public void visitError(Attribute.Error a) {
            visitAttribute(a);
        }

        public void visitAttribute(Attribute a) {
            printType("type", a.type, Details.SUMMARY);
        }

    }
    // </editor-fold>

    // <editor-fold defaultstate="collapsed" desc="Utility front end">

    /**
     * Utility class to invoke DPrinter from the command line.
     */
    static class Main {
        public static void main(String... args) throws IOException {
            Main m = new Main();
            PrintWriter out = new PrintWriter(System.out);
            try {
                if (args.length == 0)
                    m.usage(out);
                else
                    m.run(out, args);
            } finally {
                out.flush();
            }
        }

        void usage(PrintWriter out) {
            out.println("Usage:");
            out.println("  java " + Main.class.getName() + " mode [options] [javac-options]");
            out.print("where mode is one of: ");
            String sep = "";
            for (Handler h: getHandlers().values()) {
                out.print(sep);
                out.print(h.name);
                sep = ", ";
            }
            out.println();
            out.println("and where options include:");
            out.println("  -before PARSE|ENTER|ANALYZE|GENERATE|ANNOTATION_PROCESSING|ANNOTATION_PROCESSING_ROUND");
            out.println("  -after PARSE|ENTER|ANALYZE|GENERATE|ANNOTATION_PROCESSING|ANNOTATION_PROCESSING_ROUND");
            out.println("  -showPositions");
            out.println("  -showSource");
            out.println("  -showTreeSymbols");
            out.println("  -showTreeTypes");
            out.println("  -hideEmptyItems");
            out.println("  -hideNulls");
        }

        void run(PrintWriter out, String... args) throws IOException {
            JavaCompiler c = ToolProvider.getSystemJavaCompiler();
            StandardJavaFileManager fm = c.getStandardFileManager(null, null, null);

            // DPrinter options
            final Set<TaskEvent.Kind> before = EnumSet.noneOf(TaskEvent.Kind.class);
            final Set<TaskEvent.Kind> after = EnumSet.noneOf(TaskEvent.Kind.class);
            boolean showPositions = false;
            boolean showSource = false;
            boolean showTreeSymbols = false;
            boolean showTreeTypes = false;
            boolean showEmptyItems = true;
            boolean showNulls = true;

            // javac options
            Collection<String> options = new ArrayList();
            Collection<File> files = new ArrayList();
            String classpath = null;
            String classoutdir = null;

            final Handler h = getHandlers().get(args[0]);
            if (h == null)
                throw new IllegalArgumentException(args[0]);

            for (int i = 1; i < args.length; i++) {
                String arg = args[i];
                if (arg.equals("-before") && i + 1 < args.length) {
                    before.add(getKind(args[++i]));
                } else if (arg.equals("-after") && i + 1 < args.length) {
                    after.add(getKind(args[++i]));
                } else if (arg.equals("-showPositions")) {
                    showPositions = true;
                } else if (arg.equals("-showSource")) {
                    showSource = true;
                } else if (arg.equals("-showTreeSymbols")) {
                    showTreeSymbols = true;
                } else if (arg.equals("-showTreeTypes")) {
                    showTreeTypes = true;
                } else if (arg.equals("-hideEmptyLists")) {
                    showEmptyItems = false;
                } else if (arg.equals("-hideNulls")) {
                    showNulls = false;
                } else if (arg.equals("-classpath") && i + 1 < args.length) {
                    classpath = args[++i];
                } else if (arg.equals("-d") && i + 1 < args.length) {
                    classoutdir = args[++i];
                } else if (arg.startsWith("-")) {
                    int n = c.isSupportedOption(arg);
                    if (n < 0) throw new IllegalArgumentException(arg);
                    options.add(arg);
                    while (n > 0) options.add(args[++i]);
                } else if (arg.endsWith(".java")) {
                    files.add(new File(arg));
                }
            }

            if (classoutdir != null) {
                fm.setLocation(StandardLocation.CLASS_OUTPUT, Arrays.asList(new File(classoutdir)));
            }

            if (classpath != null) {
                Collection<File> path = new ArrayList();
                for (String p: classpath.split(File.pathSeparator)) {
                    if (p.isEmpty()) continue;
                    File f = new File(p);
                    if (f.exists()) path.add(f);
                }
                fm.setLocation(StandardLocation.CLASS_PATH, path);
            }
            Iterable<? extends JavaFileObject> fos = fm.getJavaFileObjectsFromFiles(files);

            JavacTask task = (JavacTask) c.getTask(out, fm, null, options, null, fos);
            final Trees trees = Trees.instance(task);

            final DPrinter dprinter = new DPrinter(out, trees);
            dprinter.source(showSource)
                    .emptyItems(showEmptyItems)
                    .nulls(showNulls)
                    .positions(showPositions)
                    .treeSymbols(showTreeSymbols)
                    .treeTypes(showTreeTypes);

            if (before.isEmpty() && after.isEmpty()) {
                if (h.name.equals("trees") && !showTreeSymbols && !showTreeTypes)
                    after.add(TaskEvent.Kind.PARSE);
                else
                    after.add(TaskEvent.Kind.ANALYZE);
            }

            task.addTaskListener(new TaskListener() {
                public void started(TaskEvent e) {
                    if (before.contains(e.getKind()))
                        handle(e);
                }

                public void finished(TaskEvent e) {
                    if (after.contains(e.getKind()))
                        handle(e);
                }

                private void handle(TaskEvent e) {
                     switch (e.getKind()) {
                         case PARSE:
                         case ENTER:
                             h.handle(e.getSourceFile().getName(),
                                     (JCTree) e.getCompilationUnit(),
                                     dprinter);
                             break;

                         default:
                             TypeElement elem = e.getTypeElement();
                             h.handle(elem.toString(),
                                     (JCTree) trees.getTree(elem),
                                     dprinter);
                             break;
                     }
                }
            });

            task.call();
        }

        TaskEvent.Kind getKind(String s) {
            return TaskEvent.Kind.valueOf(s.toUpperCase());
        }

        static protected abstract class Handler {
            final String name;
            Handler(String name) {
                this.name = name;
            }
            abstract void handle(String label, JCTree tree, DPrinter dprinter);
        }

        Map<String,Handler> getHandlers() {
            Map<String,Handler> map = new HashMap();
            for (Handler h: defaultHandlers) {
                map.put(h.name, h);
            }
            return map;
        }

        protected final Handler[] defaultHandlers = {
            new Handler("trees") {
                @Override
                void handle(String name, JCTree tree, DPrinter dprinter) {
                    dprinter.printTree(name, tree);
                    dprinter.out.println();
                }
            },

            new Handler("symbols") {
                @Override
                void handle(String name, JCTree tree, final DPrinter dprinter) {
                    TreeScanner ds = new TreeScanner() {
                        @Override
                        public void visitClassDef(JCClassDecl tree) {
                            visitDecl(tree, tree.sym);
                            super.visitClassDef(tree);
                        }

                        @Override
                        public void visitMethodDef(JCMethodDecl tree) {
                            visitDecl(tree, tree.sym);
                            super.visitMethodDef(tree);
                        }

                        @Override
                        public void visitVarDef(JCVariableDecl tree) {
                            visitDecl(tree, tree.sym);
                            super.visitVarDef(tree);
                        }

                        void visitDecl(JCTree tree, Symbol sym) {
                            dprinter.printSymbol(sym.name.toString(), sym);
                            dprinter.out.println();
                        }
                    };
                    ds.scan(tree);
                }
            },

            new Handler("types") {
                @Override
                void handle(String name, JCTree tree, final DPrinter dprinter) {
                    TreeScanner ts = new TreeScanner() {
                        @Override
                        public void scan(JCTree tree) {
                            if (tree == null) {
                                return;
                            }
                            if (tree.type != null) {
                                String label = Pretty.toSimpleString(tree);
                                dprinter.printType(label, tree.type);
                                dprinter.out.println();
                            }
                            super.scan(tree);
                        }
                    };
                    ts.scan(tree);
                }
            }
        };
    }

    // </editor-fold>

}

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