Java TreeScanner类代码示例

import com.sun.tools.javac.tree.TreeScanner; //导入依赖的package包/类
@Override
public List<JCTree> translateTopLevelClass(Env<AttrContext> env, JCTree cdef, TreeMaker make) {
    List<JCTree> result = super.translateTopLevelClass(env, cdef, make);

    new TreeScanner() {
        @Override
        public void visitBinary(JCBinary tree) {
            hasNullCheck |= tree.operator.getSimpleName().contentEquals("!=") &&
                            "resource".equals(String.valueOf(TreeInfo.name(tree.lhs))) &&
                            TreeInfo.isNull(tree.rhs);
            super.visitBinary(tree);
        }
    }.scan(result);

    return result;
}
 

import com.sun.tools.javac.tree.TreeScanner; //导入依赖的package包/类
void run() throws Exception {
    Context context = new Context();
    JavacFileManager.preRegister(context);
    final JavaCompiler tool = ToolProvider.getSystemJavaCompiler();
    JavacTask ct = (JavacTask)tool.getTask(null, null, null, null, null, Arrays.asList(new JavaSource()));
    Iterable<? extends CompilationUnitTree> elements = ct.parse();
    ct.analyze();
    Assert.check(elements.iterator().hasNext());
    JCTree topLevel = (JCTree)elements.iterator().next();
    new TreeScanner() {
        @Override
        public void visitReference(JCMemberReference tree) {
            Assert.check(tree.getOverloadKind() != null);
        }
    }.scan(topLevel);
}
 

import com.sun.tools.javac.tree.TreeScanner; //导入依赖的package包/类
@Override
public List<JCTree> translateTopLevelClass(Env<AttrContext> env, JCTree cdef, TreeMaker make) {
    List<JCTree> result = super.translateTopLevelClass(env, cdef, make);
    Map<Symbol, JCMethodDecl> declarations = new HashMap<>();
    Set<Symbol> toDump = new TreeSet<>(symbolComparator);

    new TreeScanner() {
        @Override
        public void visitMethodDef(JCMethodDecl tree) {
            if (tree.name.toString().startsWith("dump")) {
                toDump.add(tree.sym);
            }
            declarations.put(tree.sym, tree);
            super.visitMethodDef(tree);
        }
    }.scan(result);

    for (Symbol d : toDump) {
        dump(d, declarations, new HashSet<>());
    }

    return result;
}
 

import com.sun.tools.javac.tree.TreeScanner; //导入依赖的package包/类
protected void compile(TreeScanner scanner, JavaFileObject fileObject) {
  JavaCompiler compiler = JavacTool.create();
  DiagnosticCollector<JavaFileObject> diagnosticsCollector =
      new DiagnosticCollector<JavaFileObject>();
  StandardJavaFileManager fileManager = 
      compiler.getStandardFileManager(diagnosticsCollector, Locale.ENGLISH, UTF_8);
  JavacTaskImpl task = (JavacTaskImpl) compiler.getTask(CharStreams.nullWriter(), 
      fileManager,
      diagnosticsCollector,
      ImmutableList.<String>of(),
      null,
      ImmutableList.of(fileObject));
  try {
    this.sourceFile = SourceFile.create(fileObject);
    Iterable<? extends CompilationUnitTree> trees = task.parse();
    task.analyze();
    for (CompilationUnitTree tree : trees) {
      scanner.scan((JCCompilationUnit) tree);
    }
  } catch (IOException e) {
    throw new RuntimeException(e);
  }
  this.context = task.getContext();
}
 

import com.sun.tools.javac.tree.TreeScanner; //导入依赖的package包/类
private boolean isStringConcat(ExpressionTree first) {
    final boolean[] stringLiteral = {true};
    final boolean[] formatString = {false};
    new TreeScanner() {
        @Override
        public void scan(JCTree tree) {
            if (tree == null) {
                return;
            }
            switch (tree.getKind()) {
                case STRING_LITERAL:
                    break;
                case PLUS:
                    super.scan(tree);
                    break;
                default:
                    stringLiteral[0] = false;
                    break;
            }
            if (tree.getKind() == STRING_LITERAL) {
                Object value = ((LiteralTree) tree).getValue();
                if (value instanceof String && FORMAT_SPECIFIER.matcher(value.toString()).find()) {
                    formatString[0] = true;
                }
            }
        }
    }.scan((JCTree) first);
    return stringLiteral[0] && formatString[0];
}
 

import com.sun.tools.javac.tree.TreeScanner; //导入依赖的package包/类
static void test(boolean genEndPos) throws IOException {
    Context context = new Context();

    Options options = Options.instance(context);
    options.put("diags", "%b:%s/%o/%e:%_%t%m|%p%m");

    Log log = Log.instance(context);
    log.multipleErrors = true;

    JavacFileManager.preRegister(context);
    ParserFactory pfac = ParserFactory.instance(context);

    final String text =
          "public class Foo {\n"
        + "  public static void main(String[] args) {\n"
        + "    if (args.length == 0)\n"
        + "      System.out.println(\"no args\");\n"
        + "    else\n"
        + "      System.out.println(args.length + \" args\");\n"
        + "  }\n"
        + "}\n";
    JavaFileObject fo = new StringJavaFileObject("Foo", text);
    log.useSource(fo);

    CharSequence cs = fo.getCharContent(true);
    Parser parser = pfac.newParser(cs, false, genEndPos, false);
    JCTree.JCCompilationUnit tree = parser.parseCompilationUnit();
    log.setEndPosTable(fo, tree.endPositions);

    TreeScanner ts = new LogTester(log, tree.endPositions);
    ts.scan(tree);

    check(log.nerrors, 4, "errors");
    check(log.nwarnings, 4, "warnings");
}
 

import com.sun.tools.javac.tree.TreeScanner; //导入依赖的package包/类
static void test(boolean genEndPos) throws IOException {
    Context context = new Context();

    Options options = Options.instance(context);
    options.put("diags", "%b:%s/%o/%e:%_%t%m|%p%m");

    Log log = Log.instance(context);
    log.multipleErrors = true;

    JavacFileManager.preRegister(context);
    Scanner.Factory sfac = Scanner.Factory.instance(context);
    Parser.Factory pfac = Parser.Factory.instance(context);

    final String text =
          "public class Foo {\n"
        + "  public static void main(String[] args) {\n"
        + "    if (args.length == 0)\n"
        + "      System.out.println(\"no args\");\n"
        + "    else\n"
        + "      System.out.println(args.length + \" args\");\n"
        + "  }\n"
        + "}\n";
    JavaFileObject fo = new StringJavaFileObject("Foo", text);
    log.useSource(fo);

    Scanner s = sfac.newScanner(fo.getCharContent(true));
    Parser parser = pfac.newParser(s, false, genEndPos);
    JCTree.JCCompilationUnit tree = parser.compilationUnit();
    log.setEndPosTable(fo, tree.endPositions);

    TreeScanner ts = new LogTester(log, tree.endPositions);
    ts.scan(tree);

    check(log.nerrors, 4, "errors");
    check(log.nwarnings, 4, "warnings");
}
 

import com.sun.tools.javac.tree.TreeScanner; //导入依赖的package包/类
static SuggestedFix renameTypeVariable(
    TypeParameterTree typeParameter,
    Tree owningTree,
    String typeVarReplacement,
    VisitorState state) {

  Symbol typeVariableSymbol = ASTHelpers.getSymbol(typeParameter);

  // replace only the type parameter name (and not any upper bounds)
  String name = typeParameter.getName().toString();
  int pos = ((JCTree) typeParameter).getStartPosition();
  SuggestedFix.Builder fixBuilder =
      SuggestedFix.builder().replace(pos, pos + name.length(), typeVarReplacement);

  ((JCTree) owningTree)
      .accept(
          new TreeScanner() {
            @Override
            public void visitIdent(JCTree.JCIdent tree) {
              Symbol identSym = ASTHelpers.getSymbol(tree);
              if (Objects.equal(identSym, typeVariableSymbol)) {
                // Lambda parameters can be desugared early, so we need to make sure the source
                // is there. In the example below, we would try to suggest replacing the node 't'
                // with T2, since the compiler desugars to g((T t) -> false). The extra condition
                // prevents us from doing that.

                // Foo<T> {
                //   <G> void g(Predicate<G> p) {},
                //   <T> void blah() {
                //     g(t -> false);
                //   }
                // }
                if (Objects.equal(state.getSourceForNode(tree), name)) {
                  fixBuilder.replace(tree, typeVarReplacement);
                }
              }
            }
          });
  return fixBuilder.build();
}
 

import com.sun.tools.javac.tree.TreeScanner; //导入依赖的package包/类
protected void compile(TreeScanner scanner, JavaFileObject fileObject) {
  JavaCompiler compiler = JavacTool.create();
  DiagnosticCollector<JavaFileObject> diagnosticsCollector =
      new DiagnosticCollector<JavaFileObject>();
  StandardJavaFileManager fileManager =
      compiler.getStandardFileManager(diagnosticsCollector, Locale.ENGLISH, UTF_8);
  JavacTaskImpl task =
      (JavacTaskImpl)
          compiler.getTask(
              CharStreams.nullWriter(),
              fileManager,
              diagnosticsCollector,
              ImmutableList.<String>of(),
              null,
              ImmutableList.of(fileObject));
  try {
    this.sourceFile = SourceFile.create(fileObject);
    Iterable<? extends CompilationUnitTree> trees = task.parse();
    task.analyze();
    for (CompilationUnitTree tree : trees) {
      scanner.scan((JCCompilationUnit) tree);
    }
  } catch (IOException e) {
    throw new RuntimeException(e);
  }
  this.context = task.getContext();
}
 

import com.sun.tools.javac.tree.TreeScanner; //导入依赖的package包/类
/**
 * Records the super type closure of all class declarations in the given compilation unit. Called
 * after attribute is complete for a compilation unit.
 */
public void postAttribute(Env<AttrContext> result) {
  result.toplevel.accept(
      new TreeScanner() {
        @Override
        public void visitClassDef(JCClassDecl tree) {
          recordSuperClosure(tree.sym);
          super.visitClassDef(tree);
        }
      });
}
 

import com.sun.tools.javac.tree.TreeScanner; //导入依赖的package包/类
static void test(boolean genEndPos) throws Exception {
    Context context = new Context();

    Options options = Options.instance(context);
    options.put("diags", "%b:%s/%o/%e:%_%t%m|%p%m");

    Log log = Log.instance(context);
    Factory diagnosticFactory = JCDiagnostic.Factory.instance(context);
    Field defaultErrorFlagsField =
            JCDiagnostic.Factory.class.getDeclaredField("defaultErrorFlags");

    defaultErrorFlagsField.setAccessible(true);

    Set<DiagnosticFlag> defaultErrorFlags =
            (Set<DiagnosticFlag>) defaultErrorFlagsField.get(diagnosticFactory);

    defaultErrorFlags.add(DiagnosticFlag.MULTIPLE);

    JavacFileManager.preRegister(context);
    ParserFactory pfac = ParserFactory.instance(context);

    final String text =
          "public class Foo {\n"
        + "  public static void main(String[] args) {\n"
        + "    if (args.length == 0)\n"
        + "      System.out.println(\"no args\");\n"
        + "    else\n"
        + "      System.out.println(args.length + \" args\");\n"
        + "  }\n"
        + "}\n";
    JavaFileObject fo = new StringJavaFileObject("Foo", text);
    log.useSource(fo);

    CharSequence cs = fo.getCharContent(true);
    Parser parser = pfac.newParser(cs, false, genEndPos, false);
    JCTree.JCCompilationUnit tree = parser.parseCompilationUnit();
    log.setEndPosTable(fo, tree.endPositions);

    TreeScanner ts = new LogTester(log, tree.endPositions);
    ts.scan(tree);

    check(log.nerrors, 4, "errors");
    check(log.nwarnings, 4, "warnings");
}