private void parse()

in apm-agent-plugin-sdk/src/main/java/co/elastic/apm/agent/sdk/internal/db/signature/SignatureParser.java [72:173]
97 lines of code
31 McCabe index (conditional complexity)

    private void parse(Scanner scanner, String query, StringBuilder signature, @Nullable StringBuilder dbLink) {
        final Scanner.Token firstToken = scanner.scanWhile(Scanner.Token.COMMENT);
        switch (firstToken) {
            case CALL:
                signature.append("CALL");
                if (scanner.scanUntil(Scanner.Token.IDENT)) {
                    appendIdentifiers(scanner, signature, dbLink);
                }
                return;
            case DELETE:
                signature.append("DELETE");
                if (scanner.scanUntil(Scanner.Token.FROM) && scanner.scanUntil(Scanner.Token.IDENT)) {
                    signature.append(" FROM");
                    appendIdentifiers(scanner, signature, dbLink);
                }
                return;
            case INSERT:
            case REPLACE:
                signature.append(firstToken.name());
                if (scanner.scanUntil(Scanner.Token.INTO) && scanner.scanUntil(Scanner.Token.IDENT)) {
                    signature.append(" INTO");
                    appendIdentifiers(scanner, signature, dbLink);
                }
                return;
            case SELECT:
                signature.append("SELECT");
                int level = 0;
                for (Scanner.Token t = scanner.scan(); t != Scanner.Token.EOF; t = scanner.scan()) {
                    if (t == Scanner.Token.LPAREN) {
                        level++;
                    } else if (t == Scanner.Token.RPAREN) {
                        level--;
                    } else if (t == Scanner.Token.FROM) {
                        if (level == 0) {
                            if (scanner.scanToken(Scanner.Token.IDENT)) {
                                signature.append(" FROM");
                                appendIdentifiers(scanner, signature, dbLink);
                            } else {
                                return;
                            }
                        }
                    }
                }
                return;
            case UPDATE:
                signature.append("UPDATE");
                // Scan for the table name
                boolean hasPeriod = false, hasFirstPeriod = false, isDbLink = false;
                if (scanner.scanToken(Scanner.Token.IDENT)) {
                    signature.append(' ');
                    scanner.appendCurrentTokenText(signature);
                    for (Scanner.Token t = scanner.scan(); t != Scanner.Token.EOF; t = scanner.scan()) {
                        switch (t) {
                            case IDENT:
                                if (hasPeriod) {
                                    scanner.appendCurrentTokenText(signature);
                                    hasPeriod = false;
                                }
                                if (!hasFirstPeriod) {
                                    // Some dialects allow option keywords before the table name
                                    // example: UPDATE IGNORE foo.bar
                                    signature.setLength(0);
                                    signature.append("UPDATE ");
                                    scanner.appendCurrentTokenText(signature);
                                } else if (isDbLink) {
                                    if (dbLink != null) {
                                        scanner.appendCurrentTokenText(dbLink);
                                    }
                                    isDbLink = false;
                                }
                                // Two adjacent identifiers found after the first period.
                                // Ignore the secondary ones, in case they are unknown keywords.
                                break;
                            case PERIOD:
                                hasFirstPeriod = true;
                                hasPeriod = true;
                                signature.append('.');
                                break;
                            default:
                                if ("@".equals(scanner.text())) {
                                    isDbLink = true;
                                    break;
                                } else {
                                    return;
                                }
                        }
                    }
                }
                return;
            case MERGE:
                signature.append("MERGE");
                if (scanner.scanToken(Scanner.Token.INTO) && scanner.scanUntil(Scanner.Token.IDENT)) {
                    signature.append(" INTO");
                    appendIdentifiers(scanner, signature, dbLink);
                }
                return;
            default:
                query = query.trim();
                final int indexOfWhitespace = query.indexOf(' ');
                signature.append(query, 0, indexOfWhitespace > 0 ? indexOfWhitespace : query.length());
        }
    }