private void updatePackageStatement(
     CompilationUnit astCU, String[] pkgName, ASTRewrite rewriter, ICompilationUnit cu)
     throws JavaModelException {
   boolean defaultPackage = pkgName.length == 0;
   AST ast = astCU.getAST();
   if (defaultPackage) {
     // remove existing package statement
     PackageDeclaration pkg = astCU.getPackage();
     if (pkg != null) {
       int pkgStart;
       Javadoc javadoc = pkg.getJavadoc();
       if (javadoc != null) {
         pkgStart = javadoc.getStartPosition() + javadoc.getLength() + 1;
       } else {
         pkgStart = pkg.getStartPosition();
       }
       int extendedStart = astCU.getExtendedStartPosition(pkg);
       if (pkgStart != extendedStart) {
         // keep the comments associated with package declaration
         // see https://bugs.eclipse.org/bugs/show_bug.cgi?id=247757
         String commentSource = cu.getSource().substring(extendedStart, pkgStart);
         ASTNode comment =
             rewriter.createStringPlaceholder(commentSource, ASTNode.PACKAGE_DECLARATION);
         rewriter.set(astCU, CompilationUnit.PACKAGE_PROPERTY, comment, null);
       } else {
         rewriter.set(astCU, CompilationUnit.PACKAGE_PROPERTY, null, null);
       }
     }
   } else {
     org.eclipse.jdt.core.dom.PackageDeclaration pkg = astCU.getPackage();
     if (pkg != null) {
       // rename package statement
       Name name = ast.newName(pkgName);
       rewriter.set(pkg, PackageDeclaration.NAME_PROPERTY, name, null);
     } else {
       // create new package statement
       pkg = ast.newPackageDeclaration();
       pkg.setName(ast.newName(pkgName));
       rewriter.set(astCU, CompilationUnit.PACKAGE_PROPERTY, pkg, null);
     }
   }
 }
  protected ISourceLocation getSourceLocation(ASTNode node) {
    try {
      int nodeLength = compilUnit.getExtendedLength(node);

      if (nodeLength > 0) {
        int start = compilUnit.getExtendedStartPosition(node);
        int end = start + nodeLength - 1;

        if (end < start && ((node.getFlags() & 9) > 0)) {
          insert(
              messages,
              values.constructor(
                  DATATYPE_RASCAL_MESSAGE_ERROR_NODE_TYPE,
                  values.string("Recovered/Malformed node, guessing the length"),
                  values.sourceLocation(loc, 0, 0)));

          nodeLength = node.toString().length();
          end = start + nodeLength - 1;
        }

        return values.sourceLocation(
            loc,
            start,
            nodeLength,
            compilUnit.getLineNumber(start),
            compilUnit.getLineNumber(end),
            // TODO: only adding 1 at the end seems to work, need to test.
            compilUnit.getColumnNumber(start),
            compilUnit.getColumnNumber(end) + 1);
      }
    } catch (IllegalArgumentException e) {
      insert(
          messages,
          values.constructor(
              DATATYPE_RASCAL_MESSAGE_ERROR_NODE_TYPE,
              values.string("Most probably missing dependency"),
              values.sourceLocation(loc, 0, 0)));
    }
    return values.sourceLocation(loc, 0, 0, 0, 0, 0, 0);
  }
  private void createTryCatchStatement(org.eclipse.jdt.core.IBuffer buffer, String lineDelimiter)
      throws CoreException {
    List<Statement> result = new ArrayList<>(1);
    TryStatement tryStatement = getAST().newTryStatement();
    ITypeBinding[] exceptions = fAnalyzer.getExceptions();
    ImportRewriteContext context =
        new ContextSensitiveImportRewriteContext(
            fAnalyzer.getEnclosingBodyDeclaration(), fImportRewrite);

    if (!fIsMultiCatch) {
      for (int i = 0; i < exceptions.length; i++) {
        ITypeBinding exception = exceptions[i];
        CatchClause catchClause = getAST().newCatchClause();
        tryStatement.catchClauses().add(catchClause);
        SingleVariableDeclaration decl = getAST().newSingleVariableDeclaration();
        String varName = StubUtility.getExceptionVariableName(fCUnit.getJavaProject());

        String name = fScope.createName(varName, false);
        decl.setName(getAST().newSimpleName(name));
        Type type = fImportRewrite.addImport(exception, getAST(), context);
        decl.setType(type);
        catchClause.setException(decl);
        Statement st = getCatchBody(ASTNodes.getQualifiedTypeName(type), name, lineDelimiter);
        if (st != null) {
          catchClause.getBody().statements().add(st);
        }
        fLinkedProposalModel
            .getPositionGroup(GROUP_EXC_TYPE + i, true)
            .addPosition(fRewriter.track(decl.getType()), i == 0);
        fLinkedProposalModel
            .getPositionGroup(GROUP_EXC_NAME + i, true)
            .addPosition(fRewriter.track(decl.getName()), false);
      }
    } else {
      List<ITypeBinding> filteredExceptions = filterSubtypeExceptions(exceptions);
      CatchClause catchClause = getAST().newCatchClause();
      SingleVariableDeclaration decl = getAST().newSingleVariableDeclaration();
      String varName = StubUtility.getExceptionVariableName(fCUnit.getJavaProject());
      String name = fScope.createName(varName, false);
      decl.setName(getAST().newSimpleName(name));

      UnionType unionType = getAST().newUnionType();
      List<Type> types = unionType.types();
      int i = 0;
      for (ITypeBinding exception : filteredExceptions) {
        Type type = fImportRewrite.addImport(exception, getAST(), context);
        types.add(type);
        fLinkedProposalModel
            .getPositionGroup(GROUP_EXC_TYPE + i, true)
            .addPosition(fRewriter.track(type), i == 0);
        i++;
      }

      decl.setType(unionType);
      catchClause.setException(decl);
      fLinkedProposalModel
          .getPositionGroup(GROUP_EXC_NAME + 0, true)
          .addPosition(fRewriter.track(decl.getName()), false);
      Statement st = getCatchBody("Exception", name, lineDelimiter); // $NON-NLS-1$
      if (st != null) {
        catchClause.getBody().statements().add(st);
      }
      tryStatement.catchClauses().add(catchClause);
    }
    List<ASTNode> variableDeclarations = getSpecialVariableDeclarationStatements();
    ListRewrite statements =
        fRewriter.getListRewrite(tryStatement.getBody(), Block.STATEMENTS_PROPERTY);
    boolean selectedNodeRemoved = false;
    ASTNode expressionStatement = null;
    for (int i = 0; i < fSelectedNodes.length; i++) {
      ASTNode node = fSelectedNodes[i];
      if (node instanceof VariableDeclarationStatement && variableDeclarations.contains(node)) {
        AST ast = getAST();
        VariableDeclarationStatement statement = (VariableDeclarationStatement) node;
        // Create a copy and remove the initializer
        VariableDeclarationStatement copy =
            (VariableDeclarationStatement) ASTNode.copySubtree(ast, statement);
        List<IExtendedModifier> modifiers = copy.modifiers();
        for (Iterator<IExtendedModifier> iter = modifiers.iterator(); iter.hasNext(); ) {
          IExtendedModifier modifier = iter.next();
          if (modifier.isModifier()
              && Modifier.isFinal(((Modifier) modifier).getKeyword().toFlagValue())) {
            iter.remove();
          }
        }
        List<VariableDeclarationFragment> fragments = copy.fragments();
        for (Iterator<VariableDeclarationFragment> iter = fragments.iterator(); iter.hasNext(); ) {
          VariableDeclarationFragment fragment = iter.next();
          fragment.setInitializer(null);
        }
        CompilationUnit root = (CompilationUnit) statement.getRoot();
        int extendedStart = root.getExtendedStartPosition(statement);
        // we have a leading comment and the comment is covered by the selection
        if (extendedStart != statement.getStartPosition()
            && extendedStart >= fSelection.getOffset()) {
          String commentToken =
              buffer.getText(extendedStart, statement.getStartPosition() - extendedStart);
          commentToken = Strings.trimTrailingTabsAndSpaces(commentToken);
          Type type = statement.getType();
          String typeName = buffer.getText(type.getStartPosition(), type.getLength());
          copy.setType(
              (Type)
                  fRewriter.createStringPlaceholder(commentToken + typeName, type.getNodeType()));
        }
        result.add(copy);
        // convert the fragments into expression statements
        fragments = statement.fragments();
        if (!fragments.isEmpty()) {
          List<ExpressionStatement> newExpressionStatements = new ArrayList<>();
          for (Iterator<VariableDeclarationFragment> iter = fragments.iterator();
              iter.hasNext(); ) {
            VariableDeclarationFragment fragment = iter.next();
            Expression initializer = fragment.getInitializer();
            if (initializer != null) {
              Assignment assignment = ast.newAssignment();
              assignment.setLeftHandSide(
                  (Expression) fRewriter.createCopyTarget(fragment.getName()));
              assignment.setRightHandSide((Expression) fRewriter.createCopyTarget(initializer));
              newExpressionStatements.add(ast.newExpressionStatement(assignment));
            }
          }
          if (!newExpressionStatements.isEmpty()) {
            if (fSelectedNodes.length == 1) {
              expressionStatement =
                  fRewriter.createGroupNode(
                      newExpressionStatements.toArray(new ASTNode[newExpressionStatements.size()]));
            } else {
              fRewriter.replace(
                  statement,
                  fRewriter.createGroupNode(
                      newExpressionStatements.toArray(new ASTNode[newExpressionStatements.size()])),
                  null);
            }
          } else {
            fRewriter.remove(statement, null);
            selectedNodeRemoved = true;
          }
        } else {
          fRewriter.remove(statement, null);
          selectedNodeRemoved = true;
        }
      }
    }
    result.add(tryStatement);
    ASTNode replacementNode;
    if (result.size() == 1) {
      replacementNode = result.get(0);
    } else {
      replacementNode = fRewriter.createGroupNode(result.toArray(new ASTNode[result.size()]));
    }
    if (fSelectedNodes.length == 1) {
      ASTNode selectedNode = fSelectedNodes[0];

      if (selectedNode instanceof MethodReference) {
        MethodReference methodReference = (MethodReference) selectedNode;
        IMethodBinding functionalMethod =
            QuickAssistProcessor.getFunctionalMethodForMethodReference(methodReference);
        // functionalMethod is non-null and non-generic. See
        // ExceptionAnalyzer.handleMethodReference(MethodReference node).
        Assert.isTrue(functionalMethod != null && !functionalMethod.isGenericMethod());
        LambdaExpression lambda =
            QuickAssistProcessor.convertMethodRefernceToLambda(
                methodReference, functionalMethod, fRootNode, fRewriter, null, true);
        ASTNode statementInBlock = (ASTNode) ((Block) lambda.getBody()).statements().get(0);
        fRewriter.replace(statementInBlock, replacementNode, null);
        statements.insertLast(statementInBlock, null);
        return;
      }

      LambdaExpression enclosingLambda = ASTResolving.findEnclosingLambdaExpression(selectedNode);
      if (enclosingLambda != null
          && selectedNode.getLocationInParent() == LambdaExpression.BODY_PROPERTY
          && enclosingLambda.resolveMethodBinding() != null) {
        QuickAssistProcessor.changeLambdaBodyToBlock(enclosingLambda, getAST(), fRewriter);
        Block blockBody = (Block) fRewriter.get(enclosingLambda, LambdaExpression.BODY_PROPERTY);
        ASTNode statementInBlock = (ASTNode) blockBody.statements().get(0);
        fRewriter.replace(statementInBlock, replacementNode, null);
        statements.insertLast(statementInBlock, null);
        return;
      }

      if (expressionStatement != null) {
        statements.insertLast(expressionStatement, null);
      } else {
        if (!selectedNodeRemoved)
          statements.insertLast(fRewriter.createMoveTarget(selectedNode), null);
      }
      fRewriter.replace(selectedNode, replacementNode, null);
    } else {
      ListRewrite source =
          fRewriter.getListRewrite(
              fSelectedNodes[0].getParent(),
              (ChildListPropertyDescriptor) fSelectedNodes[0].getLocationInParent());
      ASTNode toMove =
          source.createMoveTarget(
              fSelectedNodes[0], fSelectedNodes[fSelectedNodes.length - 1], replacementNode, null);
      statements.insertLast(toMove, null);
    }
  }