1 /*

     2  * Copyright 2010 Sun Microsystems, Inc.  All Rights Reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  */

    23 

    24 import java.awt.BorderLayout;

    25 import java.awt.Color;

    26 import java.awt.Dimension;

    27 import java.awt.EventQueue;

    28 import java.awt.Font;

    29 import java.awt.GridBagConstraints;

    30 import java.awt.GridBagLayout;

    31 import java.awt.Rectangle;

    32 import java.awt.event.ActionEvent;

    33 import java.awt.event.ActionListener;

    34 import java.awt.event.MouseAdapter;

    35 import java.awt.event.MouseEvent;

    36 import java.io.File;

    37 import java.io.IOException;

    38 import java.io.PrintStream;

    39 import java.io.PrintWriter;

    40 import java.io.StringWriter;

    41 import java.lang.reflect.Field;

    42 import java.lang.reflect.Modifier;

    43 import java.nio.charset.Charset;

    44 import java.util.ArrayList;

    45 import java.util.Collections;

    46 import java.util.HashMap;

    47 import java.util.HashSet;

    48 import java.util.Iterator;

    49 import java.util.List;

    50 import java.util.Map;

    51 import java.util.Set;

    52 import javax.swing.DefaultComboBoxModel;

    53 import javax.swing.JComboBox;

    54 import javax.swing.JComponent;

    55 import javax.swing.JFrame;

    56 import javax.swing.JLabel;

    57 import javax.swing.JPanel;

    58 import javax.swing.JScrollPane;

    59 import javax.swing.JTextArea;

    60 import javax.swing.JTextField;

    61 import javax.swing.SwingUtilities;

    62 import javax.swing.event.CaretEvent;

    63 import javax.swing.event.CaretListener;

    64 import javax.swing.text.BadLocationException;

    65 import javax.swing.text.DefaultHighlighter;

    66 import javax.swing.text.Highlighter;

    67 import javax.tools.Diagnostic;

    68 import javax.tools.DiagnosticListener;

    69 import javax.tools.JavaFileObject;

    70 import javax.tools.StandardJavaFileManager;

    71 

    72 import com.sun.source.tree.CompilationUnitTree;

    73 import com.sun.source.util.JavacTask;

    74 import com.sun.tools.javac.api.JavacTool;

    75 import com.sun.tools.javac.code.Flags;

    76 import com.sun.tools.javac.tree.JCTree;

    77 import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;

    78 import com.sun.tools.javac.tree.JCTree.JCNewClass;

    79 import com.sun.tools.javac.tree.JCTree.JCVariableDecl;

    80 import com.sun.tools.javac.tree.TreeInfo;

    81 import com.sun.tools.javac.tree.TreeScanner;

    82 

    83 import static com.sun.tools.javac.util.Position.NOPOS;

    84 

    85 /**

    86  * Utility and test program to check validity of tree positions for tree nodes.

    87  * The program can be run standalone, or as a jtreg test.  In standalone mode,

    88  * errors can be displayed in a gui viewer. For info on command line args,

    89  * run program with no args.

    90  *

    91  * <p>

    92  * jtreg: Note that by using the -r switch in the test description below, this test

    93  * will process all java files in the langtools/test directory, thus implicitly

    94  * covering any new language features that may be tested in this test suite.

    95  */

    96 

    97 /*

    98  * @test

    99  * @bug 6919889

   100  * @summary assorted position errors in compiler syntax trees

   101  * @run main TreePosTest -q -r -ef ./tools/javac/typeAnnotations .

   102  */

   103 public class TreePosTest {

   104     /**

   105      * Main entry point.

   106      * If test.src is set, program runs in jtreg mode, and will throw an Error

   107      * if any errors arise, otherwise System.exit will be used, unless the gui

   108      * viewer is being used. In jtreg mode, the default base directory for file

   109      * args is the value of ${test.src}. In jtreg mode, the -r option can be

   110      * given to change the default base directory to the root test directory.

   111      */

   112     public static void main(String... args) {

   113         String testSrc = System.getProperty("test.src");

   114         File baseDir = (testSrc == null) ? null : new File(testSrc);

   115         boolean ok = new TreePosTest().run(baseDir, args);

   116         if (!ok) {

   117             if (testSrc != null)  // jtreg mode

   118                 throw new Error("failed");

   119             else

   120                 System.exit(1);

   121         }

   122     }

   123 

   124     /**

   125      * Run the program. A base directory can be provided for file arguments.

   126      * In jtreg mode, the -r option can be given to change the default base

   127      * directory to the test root directory. For other options, see usage().

   128      * @param baseDir base directory for any file arguments.

   129      * @param args command line args

   130      * @return true if successful or in gui mode

   131      */

   132     boolean run(File baseDir, String... args) {

   133         if (args.length == 0) {

   134             usage(System.out);

   135             return true;

   136         }

   137 

   138         List<File> files = new ArrayList<File>();

   139         for (int i = 0; i < args.length; i++) {

   140             String arg = args[i];

   141             if (arg.equals("-encoding") && i + 1 < args.length)

   142                 encoding = args[++i];

   143             else if (arg.equals("-gui"))

   144                 gui = true;

   145             else if (arg.equals("-q"))

   146                 quiet = true;

   147             else if (arg.equals("-v"))

   148                 verbose = true;

   149             else if (arg.equals("-t") && i + 1 < args.length)

   150                 tags.add(args[++i]);

   151             else if (arg.equals("-ef") && i + 1 < args.length)

   152                 excludeFiles.add(new File(baseDir, args[++i]));

   153             else if (arg.equals("-r")) {

   154                 if (excludeFiles.size() > 0)

   155                     throw new Error("-r must be used before -ef");

   156                 File d = baseDir;

   157                 while (!new File(d, "TEST.ROOT").exists()) {

   158                     d = d.getParentFile();

   159                     if (d == null)

   160                         throw new Error("cannot find TEST.ROOT");

   161                 }

   162                 baseDir = d;

   163             }

   164             else if (arg.startsWith("-"))

   165                 throw new Error("unknown option: " + arg);

   166             else {

   167                 while (i < args.length)

   168                     files.add(new File(baseDir, args[i++]));

   169             }

   170         }

   171 

   172         for (File file: files) {

   173             if (file.exists())

   174                 test(file);

   175             else

   176                 error("File not found: " + file);

   177         }

   178 

   179         if (fileCount != 1)

   180             System.err.println(fileCount + " files read");

   181         if (errors > 0)

   182             System.err.println(errors + " errors");

   183 

   184         return (gui || errors == 0);

   185     }

   186 

   187     /**

   188      * Print command line help.

   189      * @param out output stream

   190      */

   191     void usage(PrintStream out) {

   192         out.println("Usage:");

   193         out.println("  java TreePosTest options... files...");

   194         out.println("");

   195         out.println("where options include:");

   196         out.println("-gui      Display returns in a GUI viewer");

   197         out.println("-q        Quiet: don't report on inapplicable files");

   198         out.println("-v        Verbose: report on files as they are being read");

   199         out.println("-t tag    Limit checks to tree nodes with this tag");

   200         out.println("          Can be repeated if desired");

   201         out.println("-ef file  Exclude file or directory");

   202         out.println("");

   203         out.println("files may be directories or files");

   204         out.println("directories will be scanned recursively");

   205         out.println("non java files, or java files which cannot be parsed, will be ignored");

   206         out.println("");

   207     }

   208 

   209     /**

   210      * Test a file. If the file is a directory, it will be recursively scanned

   211      * for java files.

   212      * @param file the file or directory to test

   213      */

   214     void test(File file) {

   215         if (excludeFiles.contains(file)) {

   216             if (!quiet)

   217                 error("File " + file + " excluded");

   218             return;

   219         }

   220 

   221         if (file.isDirectory()) {

   222             for (File f: file.listFiles()) {

   223                 test(f);

   224             }

   225             return;

   226         }

   227 

   228         if (file.isFile() && file.getName().endsWith(".java")) {

   229             try {

   230                 if (verbose)

   231                     System.err.println(file);

   232                 fileCount++;

   233                 PosTester p = new PosTester();

   234                 p.test(read(file));

   235             } catch (ParseException e) {

   236                 if (!quiet) {

   237                     error("Error parsing " + file + "\n" + e.getMessage());

   238                 }

   239             } catch (IOException e) {

   240                 error("Error reading " + file + ": " + e);

   241             }

   242             return;

   243         }

   244 

   245         if (!quiet)

   246             error("File " + file + " ignored");

   247     }

   248 

   249     /**

   250      * Read a file.

   251      * @param file the file to be read

   252      * @return the tree for the content of the file

   253      * @throws IOException if any IO errors occur

   254      * @throws TreePosTest.ParseException if any errors occur while parsing the file

   255      */

   256     JCCompilationUnit read(File file) throws IOException, ParseException {

   257         StringWriter sw = new StringWriter();

   258         PrintWriter pw = new PrintWriter(sw);

   259         Reporter r = new Reporter(pw);

   260         JavacTool tool = JavacTool.create();

   261         Charset cs = (encoding == null ? null : Charset.forName(encoding));

   262         StandardJavaFileManager fm = tool.getStandardFileManager(r, null, null);

   263         Iterable<? extends JavaFileObject> files = fm.getJavaFileObjects(file);

   264         JavacTask task = tool.getTask(pw, fm, r, Collections.<String>emptyList(), null, files);

   265         Iterable<? extends CompilationUnitTree> trees = task.parse();

   266         pw.flush();

   267         if (r.errors > 0)

   268             throw new ParseException(sw.toString());

   269         Iterator<? extends CompilationUnitTree> iter = trees.iterator();

   270         if (!iter.hasNext())

   271             throw new Error("no trees found");

   272         JCCompilationUnit t = (JCCompilationUnit) iter.next();

   273         if (iter.hasNext())

   274             throw new Error("too many trees found");

   275         return t;

   276     }

   277 

   278     /**

   279      * Report an error. When the program is complete, the program will either

   280      * exit or throw an Error if any errors have been reported.

   281      * @param msg the error message

   282      */

   283     void error(String msg) {

   284         System.err.println(msg);

   285         errors++;

   286     }

   287 

   288     /** Number of files that have been analyzed. */

   289     int fileCount;

   290     /** Number of errors reported. */

   291     int errors;

   292     /** Flag: don't report irrelevant files. */

   293     boolean quiet;

   294     /** Flag: report files as they are processed. */

   295     boolean verbose;

   296     /** Flag: show errors in GUI viewer. */

   297     boolean gui;

   298     /** Option: encoding for test files. */

   299     String encoding;

   300     /** The GUI viewer for errors. */

   301     Viewer viewer;

   302     /** The set of tags for tree nodes to be analyzed; if empty, all tree nodes

   303      * are analyzed. */

   304     Set<String> tags = new HashSet<String>();

   305     /** Set of files and directories to be excluded from analysis. */

   306     Set<File> excludeFiles = new HashSet<File>();

   307     /** Table of printable names for tree tag values. */

   308     TagNames tagNames = new TagNames();

   309 

   310     /**

   311      * Main class for testing assertions concerning tree positions for tree nodes.

   312      */

   313     private class PosTester extends TreeScanner {

   314         void test(JCCompilationUnit tree) {

   315             sourcefile = tree.sourcefile;

   316             endPosTable = tree.endPositions;

   317             encl = new Info();

   318             tree.accept(this);

   319         }

   320 

   321         @Override

   322         public void scan(JCTree tree) {

   323             if (tree == null)

   324                 return;

   325 

   326             Info self = new Info(tree, endPosTable);

   327             if (check(self)) {

   328                 // Modifiers nodes are present throughout the tree even where

   329                 // there is no corresponding source text.

   330                 // Redundant semicolons in a class definition can cause empty

   331                 // initializer blocks with no positions.

   332                 if ((self.tag == JCTree.MODIFIERS || self.tag == JCTree.BLOCK)

   333                         && self.pos == NOPOS) {

   334                     // If pos is NOPOS, so should be the start and end positions

   335                     check("start == NOPOS", encl, self, self.start == NOPOS);

   336                     check("end == NOPOS", encl, self, self.end == NOPOS);

   337                 } else {

   338                     // For this node, start , pos, and endpos should be all defined

   339                     check("start != NOPOS", encl, self, self.start != NOPOS);

   340                     check("pos != NOPOS", encl, self, self.pos != NOPOS);

   341                     check("end != NOPOS", encl, self, self.end != NOPOS);

   342                     // The following should normally be ordered

   343                     // encl.start <= start <= pos <= end <= encl.end

   344                     // In addition, the position of the enclosing node should be

   345                     // within this node.

   346                     // The primary exceptions are for array type nodes, because of the

   347                     // need to support legacy syntax:

   348                     //    e.g.    int a[];    int[] b[];    int f()[] { return null; }

   349                     // and because of inconsistent nesting of left and right of

   350                     // array declarations:

   351                     //    e.g.    int[][] a = new int[2][];

   352                     check("encl.start <= start", encl, self, encl.start <= self.start);

   353                     check("start <= pos", encl, self, self.start <= self.pos);

   354                     if (!(self.tag == JCTree.TYPEARRAY

   355                             && (encl.tag == JCTree.VARDEF || encl.tag == JCTree.TYPEARRAY))) {

   356                         check("encl.pos <= start || end <= encl.pos",

   357                                 encl, self, encl.pos <= self.start || self.end <= encl.pos);

   358                     }

   359                     check("pos <= end", encl, self, self.pos <= self.end);

   360                     if (!(self.tag == JCTree.TYPEARRAY && encl.tag == JCTree.TYPEARRAY)) {

   361                         check("end <= encl.end", encl, self, self.end <= encl.end);

   362                     }

   363                 }

   364             }

   365 

   366             Info prevEncl = encl;

   367             encl = self;

   368             tree.accept(this);

   369             encl = prevEncl;

   370         }

   371 

   372         @Override

   373         public void visitVarDef(JCVariableDecl tree) {

   374             // enum member declarations are desugared in the parser and have

   375             // ill-defined semantics for tree positions, so for now, we

   376             // skip the synthesized bits and just check parts which came from

   377             // the original source text

   378             if ((tree.mods.flags & Flags.ENUM) != 0) {

   379                 scan(tree.mods);

   380                 if (tree.init != null) {

   381                     if (tree.init.getTag() == JCTree.NEWCLASS) {

   382                         JCNewClass init = (JCNewClass) tree.init;

   383                         if (init.args != null && init.args.nonEmpty()) {

   384                             scan(init.args);

   385                         }

   386                         if (init.def != null && init.def.defs != null) {

   387                             scan(init.def.defs);

   388                         }

   389                     }

   390                 }

   391             } else

   392                 super.visitVarDef(tree);

   393         }

   394 

   395         boolean check(Info x) {

   396             return tags.size() == 0 || tags.contains(tagNames.get(x.tag));

   397         }

   398 

   399         void check(String label, Info encl, Info self, boolean ok) {

   400             if (!ok) {

   401                 if (gui) {

   402                     if (viewer == null)

   403                         viewer = new Viewer();

   404                     viewer.addEntry(sourcefile, label, encl, self);

   405                 }

   406 

   407                 String s = self.tree.toString();

   408                 String msg = sourcefile.getName() + ": " + label + ": " +

   409                         "encl:" + encl + " this:" + self + "\n" +

   410                         s.substring(0, Math.min(80, s.length())).replaceAll("[\r\n]+", " ");

   411                 error(msg);

   412             }

   413         }

   414 

   415         JavaFileObject sourcefile;

   416         Map<JCTree, Integer> endPosTable;

   417         Info encl;

   418 

   419     }

   420 

   421     /**

   422      * Utility class providing easy access to position and other info for a tree node.

   423      */

   424     private class Info {

   425         Info() {

   426             tree = null;

   427             tag = JCTree.ERRONEOUS;

   428             start = 0;

   429             pos = 0;

   430             end = Integer.MAX_VALUE;

   431         }

   432 

   433         Info(JCTree tree, Map<JCTree, Integer> endPosTable) {

   434             this.tree = tree;

   435             tag = tree.getTag();

   436             start = TreeInfo.getStartPos(tree);

   437             pos = tree.pos;

   438             end = TreeInfo.getEndPos(tree, endPosTable);

   439         }

   440 

   441         @Override

   442         public String toString() {

   443             return tagNames.get(tree.getTag()) + "[start:" + start + ",pos:" + pos + ",end:" + end + "]";

   444         }

   445 

   446         final JCTree tree;

   447         final int tag;

   448         final int start;

   449         final int pos;

   450         final int end;

   451     }

   452 

   453     /**

   454      * Names for tree tags.

   455      * javac does not provide an API to convert tag values to strings, so this class uses

   456      * reflection to determine names of public static final int values in JCTree.

   457      */

   458     private static class TagNames {

   459         String get(int tag) {

   460             if (map == null) {

   461                 map = new HashMap<Integer, String>();

   462                 Class c = JCTree.class;

   463                 for (Field f : c.getDeclaredFields()) {

   464                     if (f.getType().equals(int.class)) {

   465                         int mods = f.getModifiers();

   466                         if (Modifier.isPublic(mods) && Modifier.isStatic(mods) && Modifier.isFinal(mods)) {

   467                             try {

   468                                 map.put(f.getInt(null), f.getName());

   469                             } catch (IllegalAccessException e) {

   470                             }

   471                         }

   472                     }

   473                 }

   474             }

   475             String name = map.get(tag);

   476             return (name == null) ? "??" : name;

   477         }

   478 

   479         private Map<Integer, String> map;

   480     }

   481 

   482     /**

   483      * Thrown when errors are found parsing a java file.

   484      */

   485     private static class ParseException extends Exception {

   486         ParseException(String msg) {

   487             super(msg);

   488         }

   489     }

   490 

   491     /**

   492      * DiagnosticListener to report diagnostics and count any errors that occur.

   493      */

   494     private static class Reporter implements DiagnosticListener<JavaFileObject> {

   495         Reporter(PrintWriter out) {

   496             this.out = out;

   497         }

   498 

   499         public void report(Diagnostic<? extends JavaFileObject> diagnostic) {

   500             out.println(diagnostic);

   501             switch (diagnostic.getKind()) {

   502                 case ERROR:

   503                     errors++;

   504             }

   505         }

   506         int errors;

   507         PrintWriter out;

   508     }

   509 

   510     /**

   511      * GUI viewer for issues found by TreePosTester. The viewer provides a drop

   512      * down list for selecting error conditions, a header area providing details

   513      * about an error, and a text area with the ranges of text highlighted as

   514      * appropriate.

   515      */

   516     private class Viewer extends JFrame {

   517         /**

   518          * Create a viewer.

   519          */

   520         Viewer() {

   521             initGUI();

   522         }

   523 

   524         /**

   525          * Add another entry to the list of errors.

   526          * @param file The file containing the error

   527          * @param check The condition that was being tested, and which failed

   528          * @param encl the enclosing tree node

   529          * @param self the tree node containing the error

   530          */

   531         void addEntry(JavaFileObject file, String check, Info encl, Info self) {

   532             Entry e = new Entry(file, check, encl, self);

   533             DefaultComboBoxModel m = (DefaultComboBoxModel) entries.getModel();

   534             m.addElement(e);

   535             if (m.getSize() == 1)

   536                 entries.setSelectedItem(e);

   537         }

   538 

   539         /**

   540          * Initialize the GUI window.

   541          */

   542         private void initGUI() {

   543             JPanel head = new JPanel(new GridBagLayout());

   544             GridBagConstraints lc = new GridBagConstraints();

   545             GridBagConstraints fc = new GridBagConstraints();

   546             fc.anchor = GridBagConstraints.WEST;

   547             fc.fill = GridBagConstraints.HORIZONTAL;

   548             fc.gridwidth = GridBagConstraints.REMAINDER;

   549 

   550             entries = new JComboBox();

   551             entries.addActionListener(new ActionListener() {

   552                 public void actionPerformed(ActionEvent e) {

   553                     showEntry((Entry) entries.getSelectedItem());

   554                 }

   555             });

   556             fc.insets.bottom = 10;

   557             head.add(entries, fc);

   558             fc.insets.bottom = 0;

   559             head.add(new JLabel("check:"), lc);

   560             head.add(checkField = createTextField(80), fc);

   561             fc.fill = GridBagConstraints.NONE;

   562             head.add(setBackground(new JLabel("encl:"), enclColor), lc);

   563             head.add(enclPanel = new InfoPanel(), fc);

   564             head.add(setBackground(new JLabel("self:"), selfColor), lc);

   565             head.add(selfPanel = new InfoPanel(), fc);

   566             add(head, BorderLayout.NORTH);

   567 

   568             body = new JTextArea();

   569             body.setFont(Font.decode(Font.MONOSPACED));

   570             body.addCaretListener(new CaretListener() {

   571                 public void caretUpdate(CaretEvent e) {

   572                     int dot = e.getDot();

   573                     int mark = e.getMark();

   574                     if (dot == mark)

   575                         statusText.setText("dot: " + dot);

   576                     else

   577                         statusText.setText("dot: " + dot + ", mark:" + mark);

   578                 }

   579             });

   580             JScrollPane p = new JScrollPane(body,

   581                     JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,

   582                     JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);

   583             p.setPreferredSize(new Dimension(640, 480));

   584             add(p, BorderLayout.CENTER);

   585 

   586             statusText = createTextField(80);

   587             add(statusText, BorderLayout.SOUTH);

   588 

   589             pack();

   590             setLocationRelativeTo(null); // centered on screen

   591             setVisible(true);

   592             setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

   593         }

   594 

   595         /** Show an entry that has been selected. */

   596         private void showEntry(Entry e) {

   597             try {

   598                 // update simple fields

   599                 setTitle(e.file.getName());

   600                 checkField.setText(e.check);

   601                 enclPanel.setInfo(e.encl);

   602                 selfPanel.setInfo(e.self);

   603                 // show file text with highlights

   604                 body.setText(e.file.getCharContent(true).toString());

   605                 Highlighter highlighter = body.getHighlighter();

   606                 highlighter.removeAllHighlights();

   607                 addHighlight(highlighter, e.encl, enclColor);

   608                 addHighlight(highlighter, e.self, selfColor);

   609                 scroll(body, getMinPos(enclPanel.info, selfPanel.info));

   610             } catch (IOException ex) {

   611                 body.setText("Cannot read " + e.file.getName() + ": " + e);

   612             }

   613         }

   614 

   615         /** Create a test field. */

   616         private JTextField createTextField(int width) {

   617             JTextField f = new JTextField(width);

   618             f.setEditable(false);

   619             f.setBorder(null);

   620             return f;

   621         }

   622 

   623         /** Add a highlighted region based on the positions in an Info object. */

   624         private void addHighlight(Highlighter h, Info info, Color c) {

   625             int start = info.start;

   626             int end = info.end;

   627             if (start == -1 && end == -1)

   628                 return;

   629             if (start == -1)

   630                 start = end;

   631             if (end == -1)

   632                 end = start;

   633             try {

   634                 h.addHighlight(info.start, info.end,

   635                         new DefaultHighlighter.DefaultHighlightPainter(c));

   636                 if (info.pos != -1) {

   637                     Color c2 = new Color(c.getRed(), c.getGreen(), c.getBlue(), (int)(.4f * 255)); // 40%

   638                     h.addHighlight(info.pos, info.pos + 1,

   639                         new DefaultHighlighter.DefaultHighlightPainter(c2));

   640                 }

   641             } catch (BadLocationException e) {

   642                 e.printStackTrace();

   643             }

   644         }

   645 

   646         /** Get the minimum valid position in a set of info objects. */

   647         private int getMinPos(Info... values) {

   648             int i = Integer.MAX_VALUE;

   649             for (Info info: values) {

   650                 if (info.start >= 0) i = Math.min(i, info.start);

   651                 if (info.pos   >= 0) i = Math.min(i, info.pos);

   652                 if (info.end   >= 0) i = Math.min(i, info.end);

   653             }

   654             return (i == Integer.MAX_VALUE) ? 0 : i;

   655         }

   656 

   657         /** Set the background on a component. */

   658         private JComponent setBackground(JComponent comp, Color c) {

   659             comp.setOpaque(true);

   660             comp.setBackground(c);

   661             return comp;

   662         }

   663 

   664         /** Scroll a text area to display a given position near the middle of the visible area. */

   665         private void scroll(final JTextArea t, final int pos) {

   666             // Using invokeLater appears to give text a chance to sort itself out

   667             // before the scroll happens; otherwise scrollRectToVisible doesn't work.

   668             // Maybe there's a better way to sync with the text...

   669             EventQueue.invokeLater(new Runnable() {

   670                 public void run() {

   671                     try {

   672                         Rectangle r = t.modelToView(pos);

   673                         JScrollPane p = (JScrollPane) SwingUtilities.getAncestorOfClass(JScrollPane.class, t);

   674                         r.y = Math.max(0, r.y - p.getHeight() * 2 / 5);

   675                         r.height += p.getHeight() * 4 / 5;

   676                         t.scrollRectToVisible(r);

   677                     } catch (BadLocationException ignore) {

   678                     }

   679                 }

   680             });

   681         }

   682 

   683         private JComboBox entries;

   684         private JTextField checkField;

   685         private InfoPanel enclPanel;

   686         private InfoPanel selfPanel;

   687         private JTextArea body;

   688         private JTextField statusText;

   689 

   690         private Color selfColor = new Color(0.f, 1.f, 0.f, 0.2f); // 20% green

   691         private Color enclColor = new Color(1.f, 0.f, 0.f, 0.2f); // 20% red

   692 

   693         /** Panel to display an Info object. */

   694         private class InfoPanel extends JPanel {

   695             InfoPanel() {

   696                 add(tagName = createTextField(20));

   697                 add(new JLabel("start:"));

   698                 add(addListener(start = createTextField(6)));

   699                 add(new JLabel("pos:"));

   700                 add(addListener(pos = createTextField(6)));

   701                 add(new JLabel("end:"));

   702                 add(addListener(end = createTextField(6)));

   703             }

   704 

   705             void setInfo(Info info) {

   706                 this.info = info;

   707                 tagName.setText(tagNames.get(info.tag));

   708                 start.setText(String.valueOf(info.start));

   709                 pos.setText(String.valueOf(info.pos));

   710                 end.setText(String.valueOf(info.end));

   711             }

   712 

   713             JTextField addListener(final JTextField f) {

   714                 f.addMouseListener(new MouseAdapter() {

   715                     @Override

   716                     public void mouseClicked(MouseEvent e) {

   717                         body.setCaretPosition(Integer.valueOf(f.getText()));

   718                         body.getCaret().setVisible(true);

   719                     }

   720                 });

   721                 return f;

   722             }

   723 

   724             Info info;

   725             JTextField tagName;

   726             JTextField start;

   727             JTextField pos;

   728             JTextField end;

   729         }

   730 

   731         /** Object to record information about an error to be displayed. */

   732         private class Entry {

   733             Entry(JavaFileObject file, String check, Info encl, Info self) {

   734                 this.file = file;

   735                 this.check = check;

   736                 this.encl = encl;

   737                 this.self= self;

   738             }

   739 

   740             @Override

   741             public String toString() {

   742                 return file.getName() + " " + check + " " + getMinPos(encl, self);

   743             }

   744 

   745             final JavaFileObject file;

   746             final String check;

   747             final Info encl;

   748             final Info self;

   749         }

   750     }

   751 }

   752