library.java

一个用java写的开源的数据库系统

        return s.substring(0, ((i < 0) ? 0
                                       : (i < s.length()) ? i
                                                          : s.length()));
    }

// fredt@users - 20020819 - patch 595854 by thomasm@users

    /**
     *  Method declaration
     *
     *
     *  @param s
     *
     *  @return
     */
    public static Integer length(String s) {
        return s == null ? null
                         : new Integer(s.length());
    }

    /**
     * Method declaration
     *
     *
     * @param search
     * @param s
     * @param start
     *
     * @return
     */
    public static int locate(String search, String s, Integer start) {

        if (s == null || search == null) {
            return 0;
        }

        int i = (start == null) ? 0
                                : start.intValue() - 1;

        return s.indexOf(search, (i < 0) ? 0
                                         : i) + 1;
    }

    /**
     * Method declaration
     *
     *
     * @param s
     *
     * @return
     */
    public static String ltrim(String s) {

        if (s == null) {
            return s;
        }

        int len = s.length(),
            i   = 0;

        while (i < len && s.charAt(i) <= ' ') {
            i++;
        }

        return (i == 0) ? s
                        : s.substring(i);
    }

    /**
     * Method declaration
     *
     *
     * @param s
     *
     * @return
     */
    public static String rawToHex(String s) {

        char         from[] = s.toCharArray();
        String       hex;
        StringBuffer to = new StringBuffer();

        for (int i = 0; i < from.length; i++) {
            hex = Integer.toHexString(from[i] & 0xffff);

            for (int j = hex.length(); j < 4; j++) {
                to.append('0');
            }

            to.append(hex);
        }

        return (to.toString());
    }

    /**
     * Method declaration
     *
     *
     * @param s
     * @param i
     *
     * @return
     */
    public static String repeat(String s, Integer count) {

        if (s == null || count == null || count.intValue() < 0) {
            return null;
        }

        int          i = count.intValue();
        StringBuffer b = new StringBuffer(s.length() * i);

        while (i-- > 0) {
            b.append(s);
        }

        return b.toString();
    }

// fredt@users - 20020903 - patch 1.7.1 - bug fix to allow multiple replaces

    /**
     * Method declaration
     *
     *
     * @param s
     * @param replace
     * @param with
     *
     * @return
     */
    public static String replace(String s, String replace, String with) {

        if (s == null || replace == null) {
            return s;
        }

        if (with == null) {
            with = "";
        }

        StringBuffer b          = new StringBuffer();
        int          start      = 0;
        int          lenreplace = replace.length();

        while (true) {
            int i = s.indexOf(replace, start);

            if (i == -1) {
                b.append(s.substring(start));

                break;
            }

            b.append(s.substring(start, i));
            b.append(with);

            start = i + lenreplace;
        }

        return b.toString();
    }

    /**
     * Method declaration
     *
     *
     * @param s
     * @param i
     *
     * @return
     */
    public static String right(String s, int i) {

        if (s == null) {
            return null;
        }

        i = s.length() - i;

        return s.substring((i < 0) ? 0
                                   : (i < s.length()) ? i
                                                      : s.length());
    }

// fredt@users 20020530 - patch 1.7.0 fredt - trim only the space character

    /**
     * Method declaration
     *
     *
     * @param s
     *
     * @return
     */
    public static String rtrim(String s) {

        if (s == null) {
            return s;
        }

        int endindex = s.length() - 1;
        int i        = endindex;

        for (; i >= 0 && s.charAt(i) == ' '; i--) {}

        return i == endindex ? s
                             : s.substring(0, i + 1);
    }

// fredt@users 20011010 - patch 460907 by fredt - soundex

    /**
     * code was rewritten by fredt@users to comply with description at
     * http://www.nara.gov/genealogy/coding.html
     * non ASCCI characters in string are ignored
     *
     * @param s
     *
     * @return
     */
    public static String soundex(String s) {

        if (s == null) {
            return s;
        }

        s = s.toUpperCase();

        int  len       = s.length();
        char b[]       = new char[] {
            '0', '0', '0', '0'
        };
        char lastdigit = '0';

        for (int i = 0, j = 0; i < len && j < 4; i++) {
            char c = s.charAt(i);
            char newdigit;

            if ("AEIOUY".indexOf(c) != -1) {
                newdigit = '7';
            } else if (c == 'H' || c == 'W') {
                newdigit = '8';
            } else if ("BFPV".indexOf(c) != -1) {
                newdigit = '1';
            } else if ("CGJKQSXZ".indexOf(c) != -1) {
                newdigit = '2';
            } else if (c == 'D' || c == 'T') {
                newdigit = '3';
            } else if (c == 'L') {
                newdigit = '4';
            } else if (c == 'M' || c == 'N') {
                newdigit = '5';
            } else if (c == 'R') {
                newdigit = '6';
            } else {
                continue;
            }

            if (j == 0) {
                b[j++]    = c;
                lastdigit = newdigit;
            } else if (newdigit <= '6') {
                if (newdigit != lastdigit) {
                    b[j++]    = newdigit;
                    lastdigit = newdigit;
                }
            } else if (newdigit == '7') {
                lastdigit = newdigit;
            }
        }

        return new String(b, 0, 4);
    }

    /**
     * Method declaration
     *
     *
     * @param i
     *
     * @return
     */
    public static String space(int i) {

        if (i < 0) {
            return null;
        }

        char c[] = new char[i];

        while (i > 0) {
            c[--i] = ' ';
        }

        return new String(c);
    }

    /**
     * Method declaration
     *
     *
     * @param s
     * @param start
     * @param length
     *
     * @return
     */

// fredt@users 20020210 - patch 500767 by adjbirch@users - modified
    public static String substring(String s, int start, Integer length) {

        if (s == null) {
            return null;
        }

        int len = s.length();

        start--;

        start = (start > len) ? len
                              : start;

        int l = len;

        if (length != null) {
            l = length.intValue();
        }

        if (start + l > len) {
            l = len - start;
        }

        return s.substring(start, start + l);
    }

    /**
     * Method declaration
     *
     *
     * @param s
     *
     * @return
     */
    public static String ucase(String s) {
        return (s == null) ? null
                           : s.toUpperCase();
    }

    // TIME AND DATE

    /**
     * Method declaration
     *
     *
     * @return
     */
    public static java.sql.Date curdate() {
        return new java.sql.Date(System.currentTimeMillis());
    }

    /**
     * Method declaration
     *
     *
     * @return
     */
    public static java.sql.Time curtime() {
        return new java.sql.Time(System.currentTimeMillis());
    }

    /**
     * Method declaration
     *
     *
     * @param d
     *
     * @return
     */
    public static String dayname(java.sql.Date d) {

        SimpleDateFormat f = new SimpleDateFormat("EEEE");

        return f.format(d).toString();
    }

    /**
     * Method declaration
     *
     *
     * @param d
     * @param part
     *
     * @return
     */
    private static int getDateTimePart(java.util.Date d, int part) {

        Calendar c = new GregorianCalendar();

        c.setTime(d);

        return c.get(part);
    }

    /**
     * Method declaration
     *
     *
     * @param t
     * @param part
     *
     * @return
     */
    private static int getTimePart(java.sql.Time t, int part) {

        Calendar c = new GregorianCalendar();

        c.setTime(t);

        return c.get(part);
    }

    /**
     * Method declaration
     *
     *
     * @param d
     *
     * @return
     */
    public static int dayofmonth(java.sql.Date d) {
        return getDateTimePart(d, Calendar.DAY_OF_MONTH);
    }

    /**
     * Method declaration
     *
     *
     * @param d
     *
     * @return
     */
    public static int dayofweek(java.sql.Date d) {
        return getDateTimePart(d, Calendar.DAY_OF_WEEK);
    }

    /**
     * Method declaration
     *
     *
     * @param d
     *
     * @return
     */
    public static int dayofyear(java.sql.Date d) {
        return getDateTimePart(d, Calendar.DAY_OF_YEAR);
    }

    /**
     * Method declaration
     *
     *
     * @param t
     *
     * @return
     */

// fredt@users 20020210 - patch 513005 by sqlbob@users (RMP) - hour
    public static int hour(java.sql.Time t) {
        return getDateTimePart(t, Calendar.HOUR_OF_DAY);
    }

    /**
     * Method declaration
     *
     *
     * @param t
     *
     * @return
     */
    public static int minute(java.sql.Time t) {
        return getDateTimePart(t, Calendar.MINUTE);
    }

// fredt@users 20020130 - patch 418017 by deforest@users - made optional
    private static int     sql_month     = 0;
    private static boolean sql_month_set = false;

    static void setSqlMonth(boolean value) {

        if (sql_month_set == false) {
            sql_month     = value ? 1
                                  : 0;
            sql_month_set = true;
        }
    }

    /**
     * Method declaration
     *
     *
     * @param d
     *
     * @return
     */
    public static int month(java.sql.Date d) {
        return getDateTimePart(d, Calendar.MONTH) + sql_month;
    }

    /**
     * Method declaration
     *
     *
     * @param d
     *
     * @return
     */
    public static String monthname(java.sql.Date d) {

        SimpleDateFormat f = new SimpleDateFormat("MMMM");

        return f.format(d).toString();
    }

    /**
     * Method declaration
     *
     *
     * @return
     */
    public static Timestamp now() {
        return new Timestamp(System.currentTimeMillis());
    }

    /**
     * Method declaration
     *
     *
     * @param d
     *
     * @return
     */
    public static int quarter(java.sql.Date d) {
        return (getDateTimePart(d, Calendar.MONTH) / 3) + 1;
    }

    /**
     * Method declaration
     *
     *
     * @param d
     *
     * @return
     */
    public static int second(java.sql.Time d) {
        return getDateTimePart(d, Calendar.SECOND);
    }

    /**
     * Method declaration
     *
     *
     * @param d
     *
     * @return
     */
    public static int week(java.sql.Date d) {
        return getDateTimePart(d, Calendar.WEEK_OF_YEAR);
    }

    /**
     * Method declaration
     *
     *
     * @param d
     *
     * @return
     */
    public static int year(java.sql.Date d) {
        return getDateTimePart(d, Calendar.YEAR);
    }

    // SYSTEM

    /**
     * Method declaration
     *
     *
     * @param conn
     *
     * @return
     *
     * @throws SQLException
     */
    public static String database(Connection conn) throws SQLException {

        Statement stat = conn.createStatement();
        String s =
            "SELECT Value FROM SYSTEM_CONNECTIONINFO WHERE KEY='DATABASE'";
        ResultSet r = stat.executeQuery(s);

        r.next();

        return r.getString(1);
    }

    /**
     * Method declaration
     *
     *
     * @param conn
     *
     * @return
     *
     * @throws SQLException
     */
    public static String user(Connection conn) throws SQLException {

        Statement stat = conn.createStatement();
        String s = "SELECT Value FROM SYSTEM_CONNECTIONINFO WHERE KEY='USER'";
        ResultSet r    = stat.executeQuery(s);

        r.next();

        return r.getString(1);
    }

    /**
     * As of 1.7.1 this is a dummy function. The return value is supplied
     * by Function.java
     *
     * @return 0
     *
     * @throws SQLException
     */
    public static int identity() throws SQLException {
        return 0;
    }

    public static boolean getAutoCommit(Connection c) {

        // hsql always creates an INTERNAL connection for
        // such calls to Library, so this is garanteed
        // to return the value contained by the
        // connection's Session, for local or remote connections
        try {
            return c.getAutoCommit();
        } catch (SQLException e) {
            return false;
        }
    }
/*
// test for soundex
    public static void main (String argv[]){
        String [] names = {"Yyhiokkk","Washington","Lee","Gutierrez","Pfister","Jackson","Tymczak","Ashcraft","VanDeusen","Deusen","Van Deusen"};
        for (int i = 0 ; i < names.length; i++ ){
            System.out.print( names[i] + " : " + soundex(names[i] + "\n"));
        }
    }
*/
}