java.util.FormattableFlags#LEFT_JUSTIFY源码实例Demo

/**
 * Returns a string representation of the user supplied formattable, accounting for any possible
 * runtime exceptions.
 *
 * @param value the value to be formatted.
 * @return a best-effort string representation of the given value, even if exceptions were thrown.
 */
private static void safeFormatTo(Formattable value, StringBuilder out, FormatOptions options) {
  // Only care about 3 specific flags for Formattable.
  int formatFlags = options.getFlags() & (FLAG_LEFT_ALIGN | FLAG_UPPER_CASE | FLAG_SHOW_ALT_FORM);
  if (formatFlags != 0) {
    // TODO: Maybe re-order the options flags to make this step easier or use a lookup table.
    // Note that reordering flags would require a rethink of how they are parsed.
    formatFlags = ((formatFlags & FLAG_LEFT_ALIGN) != 0 ? FormattableFlags.LEFT_JUSTIFY : 0)
        | ((formatFlags & FLAG_UPPER_CASE) != 0 ? FormattableFlags.UPPERCASE : 0)
        | ((formatFlags & FLAG_SHOW_ALT_FORM) != 0 ? FormattableFlags.ALTERNATE : 0);
  }
  // We may need to undo an arbitrary amount of appending if there is an error.
  int originalLength = out.length();
  Formatter formatter = new Formatter(out, FORMAT_LOCALE);
  try {
    value.formatTo(formatter, formatFlags, options.getWidth(), options.getPrecision());
  } catch (RuntimeException e) {
    out.setLength(originalLength);
    // We only use a StringBuilder to create the Formatter instance.
    try {
      formatter.out().append(getErrorString(value, e));
    } catch (IOException impossible) { }
  }
}
 

@Override
public void formatTo(Formatter formatter, int flags, int width, int precision) {
    final boolean alt = (flags & FormattableFlags.ALTERNATE) == FormattableFlags.ALTERNATE;
    final boolean upper = (flags & FormattableFlags.UPPERCASE) == FormattableFlags.UPPERCASE;
    final boolean leftJustified = (flags & FormattableFlags.LEFT_JUSTIFY) == FormattableFlags.LEFT_JUSTIFY;

    String out;
    if (!alt) {
        out = getAsMention();
    } else if (upper) {
        out = getAsTag().toUpperCase();
    } else {
        out = getAsTag();
    }

    MiscUtil.appendTo(formatter, width, precision, leftJustified, out);
}
 

@Override
public void formatTo(Formatter formatter, int flags, int width, int precision)
{
    boolean alt = (flags & FormattableFlags.ALTERNATE) == FormattableFlags.ALTERNATE;
    boolean upper = (flags & FormattableFlags.UPPERCASE) == FormattableFlags.UPPERCASE;
    boolean leftJustified = (flags & FormattableFlags.LEFT_JUSTIFY) == FormattableFlags.LEFT_JUSTIFY;

    String out;
    if (!alt)
        out = getAsMention();
    else if (upper)
        out = getAsTag().toUpperCase();
    else
        out = getAsTag();

    MiscUtil.appendTo(formatter, width, precision, leftJustified, out);
}
 

@Override
default void formatTo(Formatter formatter, int flags, int width, int precision) {
    boolean alternate = (flags & FormattableFlags.ALTERNATE) != 0;
    String representation = alternate ? this.toString() : this.getName();
    boolean uppercase = (flags & FormattableFlags.UPPERCASE) != 0;
    boolean leftAlign = (flags & FormattableFlags.LEFT_JUSTIFY) != 0;
    boolean doPad = representation.length() < width;
    String padString = null;

    if (doPad) {
        char[] spaces = new char[width - representation.length()];
        Arrays.fill(spaces, ' ');
        padString = new String(spaces);
    }

    try {
        if (doPad && !leftAlign) {
            formatter.out().append(padString);
        }

        formatter.out().append(uppercase ? representation.toUpperCase() : representation);

        if (doPad && leftAlign) {
            formatter.out().append(padString);
        }
    } catch (IOException e) {
        ExceptionLogger.getConsumer().accept(e);
    }
}
 

@Override
default void formatTo(Formatter formatter, int flags, int width, int precision) {
    boolean alternate = (flags & FormattableFlags.ALTERNATE) != 0;
    String representation = alternate ? this.toString() : this.getName();
    boolean uppercase = (flags & FormattableFlags.UPPERCASE) != 0;
    boolean leftAlign = (flags & FormattableFlags.LEFT_JUSTIFY) != 0;
    boolean doPad = representation.length() < width;
    String padString = null;

    if (doPad) {
        char[] spaces = new char[width - representation.length()];
        Arrays.fill(spaces, ' ');
        padString = new String(spaces);
    }

    try {
        if (doPad && !leftAlign) {
            formatter.out().append(padString);
        }

        formatter.out().append(uppercase ? representation.toUpperCase() : representation);

        if (doPad && leftAlign) {
            formatter.out().append(padString);
        }
    } catch (IOException e) {
        ExceptionLogger.getConsumer().accept(e);
    }
}
 

@Override
default void formatTo(Formatter formatter, int flags, int width, int precision)
{
    boolean leftJustified = (flags & FormattableFlags.LEFT_JUSTIFY) == FormattableFlags.LEFT_JUSTIFY;
    boolean upper = (flags & FormattableFlags.UPPERCASE) == FormattableFlags.UPPERCASE;
    String out = upper ? getAsMention().toUpperCase(formatter.locale()) : getAsMention();

    MiscUtil.appendTo(formatter, width, precision, leftJustified, out);
}
 

@Override
default void formatTo(Formatter formatter, int flags, int width, int precision)
{
    boolean leftJustified = (flags & FormattableFlags.LEFT_JUSTIFY) == FormattableFlags.LEFT_JUSTIFY;
    boolean upper = (flags & FormattableFlags.UPPERCASE) == FormattableFlags.UPPERCASE;
    boolean alt = (flags & FormattableFlags.ALTERNATE) == FormattableFlags.ALTERNATE;
    String out;

    if (alt)
        out = "#" + (upper ? getName().toUpperCase(formatter.locale()) : getName());
    else
        out = getAsMention();

    MiscUtil.appendTo(formatter, width, precision, leftJustified, out);
}
 

@Override
public void formatTo(Formatter formatter, int flags, int width, int precision)
{
    boolean upper = (flags & FormattableFlags.UPPERCASE) == FormattableFlags.UPPERCASE;
    boolean leftJustified = (flags & FormattableFlags.LEFT_JUSTIFY) == FormattableFlags.LEFT_JUSTIFY;

    String out = content;

    if (upper)
        out = out.toUpperCase(formatter.locale());

    appendFormat(formatter, width, precision, leftJustified, out);
}
 

/**
 * Formats the given character sequence to the given formatter. This method takes in account
 * the {@link FormattableFlags#UPPERCASE} and {@link FormattableFlags#LEFT_JUSTIFY} flags.
 *
 * @param formatter  the formatter in which to format the value.
 * @param flags      the formatting flags.
 * @param width      minimal number of characters to write, padding with {@code ' '} if necessary.
 * @param precision  number of characters to keep before truncation, or -1 if no limit.
 * @param value      the text to format.
 */
public static void formatTo(final Formatter formatter, final int flags, int width, int precision, String value) {
    /*
     * Converting to upper cases may change the string length in some locales.
     * So we need to perform this conversion before to check the length.
     */
    boolean isUpperCase = (flags & FormattableFlags.UPPERCASE) != 0;
    if (isUpperCase && (width > 0 || precision >= 0)) {
        value = value.toUpperCase(formatter.locale());
        isUpperCase = false;                            // Because conversion has already been done.
    }
    /*
     * If the string is longer than the specified "precision", truncate
     * and add "…" for letting user know that there is missing characters.
     * This loop counts the number of Unicode code points rather than characters.
     */
    int length = value.length();
    if (precision >= 0) {
        for (int i=0,n=0; i<length; i += n) {
            if (--precision < 0) {
                /*
                 * Found the amount of characters to keep. The 'n' variable can be
                 * zero only if precision == 0, in which case the string is empty.
                 */
                if (n == 0) {
                    value = "";
                } else {
                    length = (i -= n) + 1;
                    final StringBuilder buffer = new StringBuilder(length);
                    value = buffer.append(value, 0, i).append('…').toString();
                }
                break;
            }
            n = Character.charCount(value.codePointAt(i));
        }
    }
    /*
     * If the string is shorter than the minimal width, add spaces on the left or right side.
     * We double check with `width > length` since it is faster than codePointCount(…).
     */
    final String format;
    final Object[] args;
    if (width > length && (width -= value.codePointCount(0, length)) > 0) {
        format = "%s%s";
        args = new Object[] {value, value};
        args[(flags & FormattableFlags.LEFT_JUSTIFY) != 0 ? 1 : 0] = CharSequences.spaces(width);
    } else {
        format = isUpperCase ? "%S" : "%s";
        args = new Object[] {value};
    }
    formatter.format(format, args);
}