escapeprocessor.java

基于java的oa系统

/*
 Copyright (C) 2002-2004 MySQL AB

 This program is free software; you can redistribute it and/or modify
 it under the terms of version 2 of the GNU General Public License as
 published by the Free Software Foundation.
 

 There are special exceptions to the terms and conditions of the GPL 
 as it is applied to this software. View the full text of the 
 exception exception in file EXCEPTIONS-CONNECTOR-J in the directory of this 
 software distribution.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

/**
 * EscapeProcessor performs all escape code processing as outlined
 * in the JDBC spec by JavaSoft.
 *
 * @author Mark Matthews
 * @version $Id: EscapeProcessor.java,v 1.9.2.12 2004/11/02 04:26:14 mmatthew Exp $
 */
package com.mysql.jdbc;

import java.sql.SQLException;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.StringTokenizer;


class EscapeProcessor {
    /**
     * Escape process one string
     *
     * @param SQL the SQL to escape process.
     * @param serverSupportsConvertFn does the server support CONVERT() or CAST()?
     * 
     * @return the SQL after it has been escape processed.
     */
    public static final String escapeSQL(String sql, boolean serverSupportsConvertFn)
        throws java.sql.SQLException {
        boolean replaceEscapeSequence = false;
        String escapeSequence = null;
       
        if (sql == null) {
            return null;
        }

        /*
         * Short circuit this code if we don't have a matching pair of
         * "{}". - Suggested by Ryan Gustafason
         */
        int beginBrace = sql.indexOf('{');
        int nextEndBrace = (beginBrace == -1) ? (-1)
                                              : sql.indexOf('}', beginBrace);

        if (nextEndBrace == -1) {
            return sql;
        }

        StringBuffer newSql = new StringBuffer();

        EscapeTokenizer escapeTokenizer = new EscapeTokenizer(sql);

        while (escapeTokenizer.hasMoreTokens()) {
            String token = escapeTokenizer.nextToken();

            if (token.startsWith("{")) { // It's an escape code

                if (!token.endsWith("}")) {
                    throw new java.sql.SQLException(
                        "Not a valid escape sequence: " + token);
                }

                if (token.length() > 2) {
                    int nestedBrace = token.indexOf('{', 2);

                    if (nestedBrace != -1) {
                        StringBuffer buf = new StringBuffer(token.substring(0, 1));

                        String remaining = escapeSQL(token.substring(1,
                                    token.length() - 1), serverSupportsConvertFn);

                        buf.append(remaining);

                        buf.append('}');

                        token = buf.toString();
                    }
                }
                 // nested escape code

				// Compare to tokens with _no_ whitespace
				String collapsedToken = removeWhitespace(token);
				
                /*
                 * Process the escape code
                 */
                if (StringUtils.startsWithIgnoreCase(collapsedToken, "{escape")) {
                    try {
                        StringTokenizer st = new StringTokenizer(token, " '");
                        st.nextToken(); // eat the "escape" token
                        escapeSequence = st.nextToken();

                        if (escapeSequence.length() < 3) {
                            throw new java.sql.SQLException(
                                "Syntax error for escape sequence '" + token
                                + "'", SQLError.SQL_STATE_SYNTAX_ERROR);
                        }

                        escapeSequence = escapeSequence.substring(1,
                                escapeSequence.length() - 1);
                        replaceEscapeSequence = true;
                    } catch (java.util.NoSuchElementException e) {
                        throw new java.sql.SQLException(
                            "Syntax error for escape sequence '" + token + "'",
                            SQLError.SQL_STATE_SYNTAX_ERROR);
                    }
                } else if (StringUtils.startsWithIgnoreCase(collapsedToken, "{fn")) {
                	
                	
                    
                    int startPos = token.toLowerCase().indexOf("fn ") + 3;
                    int endPos = token.length() - 1; // no }
                    
                    String fnToken = token.substring(startPos, endPos);
                    
                    // We need to handle 'convert' by ourselves
                    
                    if (StringUtils.startsWithIgnoreCaseAndWs(fnToken, "convert")) {
                    	newSql.append(processConvertToken(fnToken, serverSupportsConvertFn));
                    } else {
                    	// just pass functions right to the DB
                    	newSql.append(fnToken);
                    }
                } else if (StringUtils.startsWithIgnoreCase(collapsedToken, "{d")) {
                    int startPos = token.indexOf('\'') + 1;
                    int endPos = token.lastIndexOf('\''); // no }

                    if ((startPos == -1) || (endPos == -1)) {
                        throw new java.sql.SQLException(
                            "Syntax error for DATE escape sequence '" + token
                            + "'", SQLError.SQL_STATE_SYNTAX_ERROR);
                    }

                    String argument = token.substring(startPos, endPos);

                    try {
                        StringTokenizer st = new StringTokenizer(argument, " -");
                        String year4 = st.nextToken();
                        String month2 = st.nextToken();
                        String day2 = st.nextToken();
                        String dateString = "'" + year4 + "-" + month2 + "-"
                            + day2 + "'";
                        newSql.append(dateString);
                    } catch (java.util.NoSuchElementException e) {
                        throw new java.sql.SQLException(
                            "Syntax error for DATE escape sequence '"
                            + argument + "'", SQLError.SQL_STATE_SYNTAX_ERROR);
                    }
                } else if (StringUtils.startsWithIgnoreCase(collapsedToken, "{ts")) {
                    int startPos = token.indexOf('\'') + 1;
                    int endPos = token.lastIndexOf('\''); // no }

                    if ((startPos == -1) || (endPos == -1)) {
                        throw new java.sql.SQLException(
                            "Syntax error for TIMESTAMP escape sequence '"
                            + token + "'", SQLError.SQL_STATE_SYNTAX_ERROR);
                    }

                    String argument = token.substring(startPos, endPos);

                    try {
                        StringTokenizer st = new StringTokenizer(argument,
                                " .-:");
                        String year4 = st.nextToken();
                        String month2 = st.nextToken();
                        String day2 = st.nextToken();
                        String hour = st.nextToken();
                        String minute = st.nextToken();
                        String second = st.nextToken();

                        /*
                         * For now, we get the fractional seconds
                         * part, but we don't use it, as MySQL doesn't
                         * support it in it's TIMESTAMP data type
                         *
                        String fractionalSecond = "";

                        if (st.hasMoreTokens()) {
                            fractionalSecond = st.nextToken();
                        }
                        */
                        /*
                         * Use the full format because number format
                         * will not work for "between" clauses.
                         *
                         * Ref. Mysql Docs
                         *
                         * You can specify DATETIME, DATE and TIMESTAMP values
                         * using any of a common set of formats:
                         *
                         * As a string in either 'YYYY-MM-DD HH:MM:SS' or
                         * 'YY-MM-DD HH:MM:SS' format.
                         *
                         * Thanks to Craig Longman for pointing out this bug
                         */
                        newSql.append("'").append(year4).append("-")
                              .append(month2).append("-").append(day2)
                              .append(" ").append(hour).append(":")
                              .append(minute).append(":").append(second).append("'");
                    } catch (java.util.NoSuchElementException e) {
                        throw new java.sql.SQLException(
                            "Syntax error for TIMESTAMP escape sequence '"
                            + argument + "'", SQLError.SQL_STATE_SYNTAX_ERROR);
                    }
                } else if (StringUtils.startsWithIgnoreCase(collapsedToken, "{t")) {
                    int startPos = token.indexOf('\'') + 1;
                    int endPos = token.lastIndexOf('\''); // no }