sqlparser.java

第三方的SQL Server and Sybase的jdbc dirver,速度更快

                    break;
                case ')':
                    parenCnt--;
                    out[d++] = c; s++;
                    break;
                default:
                    out[d++] = c; s++;
                    break;
            }
        }

        String args = String.valueOf(out, argStart, d - argStart).trim();

        d = argStart;
        mustbe(')', false);
        terminator = tc;
        skipWhiteSpace();

        //
        // Process convert scalar function.
        // Arguments need to be reversed and the data type
        // argument converted to an SQL server type
        //
        if (name.equals("convert") && arg2Start < args.length() - 1) {
            String arg2 = args.substring(arg2Start + 1).trim().toLowerCase();
            String dataType = (String) cvMap.get(arg2);

            if (dataType == null) {
                // Will get server error if invalid type passed
                dataType = arg2;
            }

            copyLiteral("convert(");
            copyLiteral(dataType);
            out[d++] = ',';
            copyLiteral(args.substring(0, arg2Start));
            out[d++] = ')';

            return;
        }

        //
        // See if function mapped
        //
        String fn;
        if (connection.getServerType() == Driver.SQLSERVER) {
            fn = (String) msFnMap.get(name);
            if (fn == null) {
                fn = (String) fnMap.get(name);
            }
        } else {
            fn = (String) fnMap.get(name);
        }
        if (fn == null) {
            // Not mapped so assume simple case
            copyLiteral(name);
            out[d++] = '(';
            copyLiteral(args);
            out[d++] = ')';
            return;
        }
        //
        // Process timestamp interval constants
        //
        if (args.length() > 8
            && args.substring(0, 8).equalsIgnoreCase("sql_tsi_")) {
            args = args.substring(8);
            if (args.length() > 11
                && args.substring(0, 11).equalsIgnoreCase("frac_second")) {
                args = "millisecond" + args.substring(11);
            }
        }
        //
        // Substitute mapped function name and arguments
        //
        final int len = fn.length();
        for (int i = 0; i < len; i++) {
            final char c = fn.charAt(i);
            if (c == '$') {
                // Substitute arguments
                copyLiteral(args);
            } else {
                out[d++] = c;
            }
        }
    }

    /**
     * Processes the JDBC escape {escape 'X'}.
     *
     * @throws SQLException
     */
    private void likeEscape() throws SQLException {
        copyLiteral("escape ");
        skipWhiteSpace();

        if (in[s] == '\'' || in[s] == '"') {
            copyString();
        } else {
            mustbe('\'', true);
        }

        skipWhiteSpace();
    }

    /**
     * Processes the JDBC escape sequences.
     *
     * @throws SQLException
     */
    private void escape() throws SQLException {
        char tc = terminator;
        terminator = '}';
        StringBuffer escBuf = new StringBuffer();
        s++;
        skipWhiteSpace();

        if (in[s] == '?') {
            copyParam("@return_status", -1);
            skipWhiteSpace();
            mustbe('=', false);
            skipWhiteSpace();

            while (Character.isLetter(in[s])) {
                escBuf.append(Character.toLowerCase(in[s++]));
            }

            skipWhiteSpace();
            String esc = escBuf.toString();

            if (esc.equals("call")) {
                callEscape();
            } else {
                throw new SQLException(
                        Messages.get("error.parsesql.syntax",
                                "call",
                                String.valueOf(s)),
                        "22019");
            }
        } else {
            while (Character.isLetter(in[s])) {
                escBuf.append(Character.toLowerCase(in[s++]));
            }

            skipWhiteSpace();
            String esc = escBuf.toString();

            if (esc.equals("call")) {
                callEscape();
            } else if (esc.equals("t")) {
                if (!getDateTimeField(timeMask)) {
                    throw new SQLException(
                            Messages.get("error.parsesql.syntax",
                                         "time",
                                         String.valueOf(s)),
                            "22019");
                }
            } else if (esc.equals("d")) {
                if (!getDateTimeField(dateMask)) {
                    throw new SQLException(
                            Messages.get("error.parsesql.syntax",
                                         "date",
                                         String.valueOf(s)),
                            "22019");
                }
            } else if (esc.equals("ts")) {
                if (!getDateTimeField(timestampMask)) {
                    throw new SQLException(
                            Messages.get("error.parsesql.syntax",
                                         "timestamp",
                                         String.valueOf(s)),
                            "22019");
                }
            } else if (esc.equals("oj")) {
                outerJoinEscape();
            } else if (esc.equals("fn")) {
                functionEscape();
            } else if (esc.equals("escape")) {
                likeEscape();
            } else {
                throw new SQLException(
                        Messages.get("error.parsesql.badesc",
                                esc,
                                String.valueOf(s)),
                        "22019");
            }
        }

        mustbe('}', false);
        terminator = tc;
    }

    /**
     * Extracts the first table name following the keyword FROM.
     *
     * @return the table name as a <code>String</code>
     */
    private String getTableName() throws SQLException {
        StringBuffer name = new StringBuffer(128);
        copyWhiteSpace();
        char c = (s < len) ? in[s] : ' ';
        if (c == '{') {
            // Start of {oj ... } we can assume that there is
            // more than one table in select and therefore
            // it would not be updateable.
            return "";
        }
        //
        // Skip any leading comments before first table name
        //
        while (c == '/' || c == '-' && s + 1 < len) {
            if (c == '/') {
                if (in[s + 1] == '*') {
                    skipMultiComments();
                } else {
                    break;
                }
            } else {
                if (in[s + 1] == '-') {
                    skipSingleComments();
                } else {
                    break;
                }
            }
            copyWhiteSpace();
            c = (s < len) ? in[s] : ' ';
        }

        if (c == '{') {
            // See comment above
            return "";
        }
        //
        // Now process table name
        //
        while (s < len) {
            if (c == '[' || c == '"') {
                int start = d;
                copyString();
                name.append(String.valueOf(out, start, d - start));
                copyWhiteSpace();
                c = (s < len) ? in[s] : ' ';
            } else {
                int start = d;
                c = (s < len) ? in[s++] : ' ';
                while ((isIdentifier(c))
                       && c != '.'
                       && c != ',') {
                    out[d++] = c;
                    c = (s < len) ? in[s++] : ' ';
                }
                name.append(String.valueOf(out, start, d - start));
                s--;
                copyWhiteSpace();
                c = (s < len) ? in[s] : ' ';
            }
            if (c != '.') {
                break;
            }
            name.append(c);
            out[d++] = c; s++;
            copyWhiteSpace();
            c = (s < len) ? in[s] : ' ';
        }
        return name.toString();
    }

    /**
     * Parses the SQL statement processing JDBC escapes and parameter markers.
     *
     * @param extractTable true to return the first table name in the FROM clause of a select
     * @return The processed SQL statement, any procedure name, the first
     * SQL keyword and (optionally) the first table name as elements 0 1, 2 and 3 of the
     * returned <code>String[]</code>.
     * @throws SQLException
     */
    String[] parse(boolean extractTable) throws SQLException {
        boolean isSelect   = false;
        boolean isModified = false;
        boolean isSlowScan = true;
        try {
            while (s < len) {
                final char c = in[s];

                switch (c) {
                    case '{':
                        escape();
                        isModified = true;
                        break;
                    case '[':
                    case '"':
                    case '\'':
                        copyString();
                        break;
                    case '?':
                        copyParam(null, d);
                        break;
                    case '/':
                        if (s+1 < len && in[s+1] == '*') {
                            skipMultiComments();
                        } else {
                            out[d++] = c; s++;
                        }
                        break;
                    case '-':
                        if (s+1 < len && in[s+1] == '-') {
                            skipSingleComments();
                        } else {
                            out[d++] = c; s++;
                        }
                        break;
                    default:
                        if (isSlowScan && Character.isLetter(c)) {
                            if (keyWord == null) {
                                keyWord = copyKeyWord();
                                if (keyWord.equals("select")) {
                                    isSelect = true;
                                }
                                isSlowScan = extractTable && isSelect;
                                break;
                            }
                            if (extractTable && isSelect) {
                                String sqlWord = copyKeyWord();
                                if (sqlWord.equals("from")) {
                                    // Ensure only first 'from' is processed
                                    isSlowScan = false;
                                    tableName = getTableName();
                                }
                                break;
                            }
                        }

                        out[d++] = c; s++;
                        break;
                }
            }

            //
            // Impose a reasonable maximum limit on the number of parameters
            // unless the connection is sending statements unprepared (i.e. by
            // building a plain query) and this is not a procedure call.
            //
            if (params != null && params.size() > 255
                    && connection.getPrepareSql() != TdsCore.UNPREPARED
                    && procName != null) {
                int limit = 255; // SQL 6.5 and Sybase < 12.50
                if (connection.getServerType() == Driver.SYBASE) {
                    if (connection.getDatabaseMajorVersion() > 12 ||
                            connection.getDatabaseMajorVersion() == 12 &&
                            connection.getDatabaseMinorVersion() >= 50) {
                        limit = 2000; // Actually 2048 but allow some head room
                    }
                } else {
                    if (connection.getDatabaseMajorVersion() == 7) {
                        limit = 1000; // Actually 1024
                    } else
                    if (connection.getDatabaseMajorVersion() > 7) {
                        limit = 2000; // Actually 2100
                    }

                }
                if (params.size() > limit) {
                    throw new SQLException(
                        Messages.get("error.parsesql.toomanyparams",
                                Integer.toString(limit)),
                        "22025");
                }
            }
            String result[] = new String[4];

            // return sql and procname
            result[0] = (isModified) ? new String(out, 0, d) : sql;
            result[1] = procName;
            result[2] = (keyWord == null) ? "" : keyWord;
            result[3] = tableName;
            return result;
        } catch (IndexOutOfBoundsException e) {
            // Should only come here if string is invalid in some way.
            throw new SQLException(
                    Messages.get("error.parsesql.missing",
                            String.valueOf(terminator)),
                    "22025");
        }
    }
}