libjava/classpath/java/util/Formattable.java

   1 /* Formattable.java -- Objects which can be passed to a Formatter
   2    Copyright (C) 2005 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package java.util;
  40
  41 /**
  42  * <p>
  43  * The <code>Formattable</code> interface is used to provide customised
  44  * formatting to arbitrary objects via the {@link Formatter}.  The
  45  * {@link #formatTo} method is called for <code>Formattable</code>
  46  * objects used with the 's' conversion operator, allowing the object
  47  * to provide its own formatting of its internal data.
  48  * </p>
  49  * <p>
  50  * Thread safety is left up to the implementing class.  Thus,
  51  * {@link Formattable} objects are not guaranteed to be thread-safe,
  52  * and users should make their own provisions for multiple thread access.
  53  * </p>
  54  *
  55  * @author Tom Tromey (tromey@redhat.com)
  56  * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
  57  * @since 1.5
  58  */
  59 public interface Formattable
  60 {
  61
  62   /**
  63    * Formats the object using the supplied formatter to the specification
  64    * provided by the given flags, width and precision.
  65    *
  66    * @param formatter the formatter to use for formatting the object.
  67    *                  The formatter gives access to the output stream
  68    *                  and locale via {@link Formatter#out()} and
  69    *                  {@link Formatter#locale()} respectively.
  70    * @param flags a bit mask constructed from the flags in the
  71    *              {@link FormattableFlags} class.  When no flags
  72    *              are set, the implementing class should use its
  73    *              defaults.
  74    * @param width the minimum number of characters to include.
  75    *              A value of -1 indicates no minimum.  The remaining
  76    *              space is padded with ' ' either on the left
  77    *              (the default) or right (if left justification is
  78    *              specified by the flags).
  79    * @param precision the maximum number of characters to include.
  80    *              A value of -1 indicates no maximum.  This value
  81    *              is applied prior to the minimum (the width).  Thus,
  82    *              a value may meet the minimum width initially, but
  83    *              not when the width value is applied, due to
  84    *              characters being removed by the precision value.
  85    * @throws IllegalFormatException if there is a problem with
  86    *                                the syntax of the format
  87    *                                specification or a mismatch
  88    *                                between it and the arguments.
  89    */
  90   public void formatTo(Formatter formatter, int flags, int width,
  91                        int precision);
  92 }