library.java

hsqldb是100％java实现的数据库,是一个开放源代码的JAVA数据库 l 具有标准的SQL语法和JAVA接口 l HSQLDB可以自由使用和分发 l 非常简洁和快速的

            return s1;
        }

        if (start + length > len1) {
            length = len1 - start;
        }

        return s1.substring(0, start) + s2 + s1.substring(start + length);
    }

    /**
     * Returns a copy of the given <code>String</code>, with all upper case
     * characters converted to lower case. This uses the default Java String
     * conversion.
     * @param s the <code>String</code> from which to produce a lower case
     *      version
     * @return a lower case version of <code>s</code>
     */
    public static String lcase(String s) {
        return (s == null) ? null
                           : s.toLowerCase();
    }

    /**
     * Returns the leftmost <code>count</code> characters from the given
     * <code>String</code>. <p>
     *
     * <b>Note:</b> boundry conditions are handled in the following order of
     * precedence:
     *
     * <UL>
     *  <LI> if <code>s</code> is <code>null</code>, then <code>null</code>
     *      is returned
     *  <LI> if <code>count</code> is less than 1, then a zero-length
     *       <code>String</code> is returned
     *  <LI> if <code>count</code> is greater than the length of <code>s</code>,
     *      then a copy of <code>s</code> is returned
     * </UL>
     * @param s the <code>String</code> from which to retrieve the leftmost
     *      characters
     * @param count the count of leftmost characters to retrieve
     * @return the leftmost <code>count</code> characters of <code>s</code>
     */
    public static String left(String s, int count) {

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

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

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

    /**
     * Returns the number of characters in the given <code>String</code>.
     * This includes trailing blanks.
     *
     * @param s the <code>String</code> for which to determine length
     * @return the length of <code>s</code>, including trailing blanks
     */
    public static Integer length(String s) {
        return s == null ? null
                         : ValuePool.getInt(s.length());
    }

    /**
     * Returns the number of bytes in the given <code>String</code>.
     * This includes trailing blanks.
     *
     * @param s the <code>String</code> for which to determine the octet length
     * @return the octet length of <code>s</code>, including trailing blanks
     * @since 1.7.2
     */
    public static Integer octetLength(String s) {
        return s == null ? null
                         : ValuePool.getInt(s.length() * 2);
    }

    /**
     * Returns the number of bits in the given <code>String</code>.
     * This includes trailing blanks.
     *
     * @param s the <code>String</code> for which to determine the bit length
     * @return the bit length of <code>s</code>, including trailing blanks
     * @since 1.7.2
     */
    public static Integer bitLength(String s) {
        return s == null ? null
                         : ValuePool.getInt(s.length() * 16);
    }

    /**
     * Returns the starting position of the first occurrence of
     * the given <code>search</code> <code>String</code> object within
     * the given <code>String</code> object, <code>s</code>.
     *
     * The search for the first occurrence of <code>search</code> begins with
     * the first character position in <code>s</code>, unless the optional
     * argument, <code>start</code>, is specified (non-null). If
     * <code>start</code> is specified, the search begins with the character
     * position indicated by the value of <code>start</code>, where the
     * first character position in <code>s</code> is indicated by the value 1.
     * If <code>search</code> is not found within <code>s</code>, the
     * value 0 is returned.
     * @param search the <code>String</code> occurence to find in <code>s</code>
     * @param s the <code>String</code> within which to find the first
     *      occurence of <code>search</code>
     * @param start the optional character position from which to start
     *      looking in <code>s</code>
     * @return the one-based starting position of the first occurrence of
     *      <code>search</code> within <code>s</code>, or 0 if not found
     */
    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;
    }

    /**
     * As locate but from start position l. <p>
     *
     * @param search the <code>String</code> occurence to find in <code>s</code>
     * @param s the <code>String</code> within which to find the first
     *      occurence of <code>search</code>
     * @return the one-based starting position of the first occurrence of
     *      <code>search</code> within <code>s</code>, or 0 if not found
     */
    public static int position(String search, String s) {
        return locate(search, s, null);
    }

    /**
     * Returns the characters of the given <code>String</code>, with the
     * leading spaces removed. Characters such as TAB are not removed.
     *
     * @param s the <code>String</code> from which to remove the leading blanks
     * @return the characters of the given <code>String</code>, with the leading
     *      spaces removed
     */
    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);
    }

    /**
     * Converts a raw binary value, as represented by the given
     * <code>String</code>, to the equivalent <code>String</code>
     * of hexidecimal digit characters. <p>
     *
     * This conversion has the effect of expanding the character count 1:4.
     *
     * @param s the raw binary value, as a <code>String</code>
     * @return an equivalent <code>String</code> of hexidecimal digit characters
     */
    public static String rawToHex(String s) {

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

        char[]       from = s.toCharArray();
        String       hex;
        StringBuffer to = new StringBuffer(4 * s.length());

        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());
    }

    /**
     * Returns a <code>String</code> composed of the given <code>String</code>,
     * repeated  <code>count</code> times.
     *
     * @param s the <code>String</code> to repeat
     * @param count the number of repetitions
     * @return the given <code>String</code>, repeated <code>count</code> times
     */
    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

    /**
     * Replaces all occurrences of <code>replace</code> in <code>s</code>
     * with the <code>String</code> object: <code>with</code>
     * @param s the target for replacement
     * @param replace the substring(s), if any, in <code>s</code> to replace
     * @param with the value to substitute for <code>replace</code>
     * @return <code>s</code>, with all occurences of <code>replace</code>
     *      replaced by <code>with</code>
     */
    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();
    }

    /**
     * Returns the rightmost <code>count</code> characters of the given
     * <code>String</code>, <code>s</code>. <p>
     *
     * <b>Note:</b> boundry conditions are handled in the following order of
     * precedence: <p>
     *
     * <UL>
     *  <LI> if <code>s</code> is <code>null</code>, <code>null</code> is returned
     *  <LI> if <code>count</code> is less than one, a zero-length
     *      <code>String</code> is returned
     *  <LI> if <code>count</code> is greater than the length of <code>s</code>,
     *      a copy of <code>s</code> is returned
     * </UL>
     * @param s the <code>String</code> from which to retrieve the rightmost
     *      <code>count</code> characters
     * @param count the number of rightmost characters to retrieve
     * @return the rightmost <code>count</code> characters of <code>s</code>
     */
    public static String right(String s, int count) {

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

        count = s.length() - count;

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

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

    /**
     * Returns the characters of the given <code>String</code>, with trailing
     * spaces removed.
     * @param s the <code>String</code> from which to remove the trailing blanks
     * @return the characters of the given <code>String</code>, with the
     * trailing spaces removed
     */
    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);
    }

    /**
     * Returns the character sequence <code>s</code>, with the leading,
     * trailing or both the leading and trailing occurences of the first
     * character of the character sequence <code>trimstr</code> removed. <p>
     *
     * This method is in support of the standard SQL String function TRIM.
     * Ordinarily, the functionality of this method is accessed from SQL using
     * the following syntax: <p>
     *
     * <pre class="SqlCodeExample">
     * &lt;trim function&gt; ::= TRIM &lt;left paren&gt; &lt;trim operands&gt; &lt;right paren&gt;
     * &lt;trim operands&gt; ::= [ [ &lt;trim specification&gt; ] [ &lt;trim character&gt; ] FROM ] &lt;trim source&gt;
     * &lt;trim source&gt; ::= &lt;character value expression&gt;
     * &lt;trim specification&gt; ::= LEADING | TRAILING | BOTH
     * &lt;trim character&gt; ::= &lt;character value expression&gt;
     * </pre>
     *
     * @param s the string to trim
     * @param trimstr the character whose occurences will be removed
     * @param leading if true, remove leading occurences
     * @param trailing if true, remove trailing occurences
     * @return s, with the leading, trailing or both the leading and trailing
     *      occurences of the first character of <code>trimstr</code> removed
     * @since 1.7.2
     */
    public static String trim(String s, String trimstr, boolean leading,
                              boolean trailing) {

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

        int trim     = trimstr.charAt(0);
        int endindex = s.length();

        if (trailing) {
            for (--endindex; endindex >= 0 && s.charAt(endindex) == trim;
                    endindex--) {}

            endindex++;
        }

        if (endindex == 0) {
            return "";
        }

        int startindex = 0;

        if (leading) {
            while (startindex < endindex && s.charAt(startindex) == trim) {
                startindex++;
            }
        }

        if (startindex == 0 && endindex == s.length()) {
            return s;
        } else {
            return s.substring(startindex, endindex);