content: /*
   * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code 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
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  package java.util;
  
  import java.io.IOException;
  
  /**
   * The <tt>Formattable</tt> interface must be implemented by any class that
   * needs to perform custom formatting using the <tt>'s'</tt> conversion
   * specifier of {@link Formatter}.  This interface allows basic
   * control for formatting arbitrary objects.
   *
   * For example, the following class prints out different representations of a
   * stock's name depending on the flags and length constraints:
   *
   * {@code
   *   import java.nio.CharBuffer;
   *   import java.util.Formatter;
   *   import java.util.Formattable;
   *   import java.util.Locale;
   *   import static java.util.FormattableFlags.*;
   *
   *  ...
   *
   *   public class StockName implements Formattable {
   *       private String symbol, companyName, frenchCompanyName;
   *       public StockName(String symbol, String companyName,
   *                        String frenchCompanyName) {
   *           ...
   *       }
   *
   *       ...
   *
   *       public void formatTo(Formatter fmt, int f, int width, int precision) {
   *           StringBuilder sb = new StringBuilder();
   *
   *           // decide form of name
   *           String name = companyName;
   *           if (fmt.locale().equals(Locale.FRANCE))
   *               name = frenchCompanyName;
   *           boolean alternate = (f & ALTERNATE) == ALTERNATE;
   *           boolean usesymbol = alternate || (precision != -1 && precision < 10);
   *           String out = (usesymbol ? symbol : name);
   *
   *           // apply precision
   *           if (precision == -1 || out.length() < precision) {
   *               // write it all
   *               sb.append(out);
   *           } else {
   *               sb.append(out.substring(0, precision - 1)).append('*');
   *           }
   *
   *           // apply width and justification
   *           int len = sb.length();
   *           if (len < width)
   *               for (int i = 0; i < width - len; i++)
   *                   if ((f & LEFT_JUSTIFY) == LEFT_JUSTIFY)
   *                       sb.append(' ');
   *                   else
   *                       sb.insert(0, ' ');
   *
   *           fmt.format(sb.toString());
   *       }
   *
   *       public String toString() {
   *           return String.format("%s - %s", symbol, companyName);
   *       }
   *   }
   * }
   *
   * <p> When used in conjunction with the {@link Formatter}, the above
   * class produces the following output for various format strings.
   *
   * {@code
   *   Formatter fmt = new Formatter();
   *   StockName sn = new StockName("HUGE", "Huge Fruit, Inc.",
   *                                "Fruit Titanesque, Inc.");
   *   fmt.format("%s", sn);                   //   -> "Huge Fruit, Inc."
   *   fmt.format("%s", sn.toString());        //   -> "HUGE - Huge Fruit, Inc."
   *   fmt.format("%#s", sn);                  //   -> "HUGE"
   *   fmt.format("%-10.8s", sn);              //   -> "HUGE      "
   *   fmt.format("%.12s", sn);                //   -> "Huge Fruit,*"
   *   fmt.format(Locale.FRANCE, "%25s", sn);  //   -> "   Fruit Titanesque, Inc."
   * }
   *
   * <p> Formattables are not necessarily safe for multithreaded access.  Thread
   * safety is optional and may be enforced by classes that extend and implement
   * this interface.
   *
   * <p> Unless otherwise specified, passing a <tt>null</tt> argument to
   * any method in this interface will cause a {@link
   * NullPointerException} to be thrown.
   *
   * @since  1.5
   */
  public interface Formattable {
  
      /**
       * Formats the object using the provided {@link Formatter formatter}.
       *
       * @param  formatter
       *         The {@link Formatter formatter}.  Implementing classes may call
       *         {@link Formatter#out() formatter.out()} or {@link
       *         Formatter#locale() formatter.locale()} to obtain the {@link
       *         Appendable} or {@link Locale} used by this
       *         <tt>formatter</tt> respectively.
       *
       * @param  flags
       *         The flags modify the output format.  The value is interpreted as
       *         a bitmask.  Any combination of the following flags may be set:
       *         {@link FormattableFlags#LEFT_JUSTIFY}, {@link
       *         FormattableFlags#UPPERCASE}, and {@link
       *         FormattableFlags#ALTERNATE}.  If no flags are set, the default
       *         formatting of the implementing class will apply.
       *
       * @param  width
       *         The minimum number of characters to be written to the output.
       *         If the length of the converted value is less than the
       *         <tt>width</tt> then the output will be padded by
       *         <tt>'&nbsp;&nbsp;'</tt> until the total number of characters
       *         equals width.  The padding is at the beginning by default.  If
       *         the {@link FormattableFlags#LEFT_JUSTIFY} flag is set then the
       *         padding will be at the end.  If <tt>width</tt> is <tt>-1</tt>
       *         then there is no minimum.
       *
       * @param  precision
       *         The maximum number of characters to be written to the output.
       *         The precision is applied before the width, thus the output will
       *         be truncated to <tt>precision</tt> characters even if the
       *         <tt>width</tt> is greater than the <tt>precision</tt>.  If
       *         <tt>precision</tt> is <tt>-1</tt> then there is no explicit
       *         limit on the number of characters.
       *
       * @throws  IllegalFormatException
       *          If any of the parameters are invalid.  For specification of all
       *          possible formatting errors, see the <a
       *          href="../util/Formatter.html#detail">Details</a> section of the
       *          formatter class specification.
       */
      void formatTo(Formatter formatter, int flags, int width, int precision);
  }
  