001    /* Appendable.java -- Something to which characters can be appended
002       Copyright (C) 2004 Free Software Foundation
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    package java.lang;
039    
040    import java.io.IOException;
041    
042    /**
043     * <p>
044     * An <code>Appendable</code> object is one to which a sequence of Unicode
045     * characters can be added.  The appended characters must be valid Unicode
046     * characters, and may include supplementary characters, composed of multiple
047     * 16-bit <code>char</code> values.
048     * </p>
049     * <p>
050     * The behaviour of the <code>Appendable</code> object is heavily dependent
051     * on the particular implementation being used.  Some implementations may be
052     * thread-safe, while others may not.  Likewise, some implementing classes
053     * may produce errors which aren't propogated to the invoking class, due
054     * to differences in the error handling used.
055     * </p>
056     * <p>
057     * <strong>Note</strong>: implementation of this interface is required for
058     * any class that wishes to receive data from a <code>Formatter</code>
059     * instance.
060     * </p>
061     *
062     * @author Tom Tromey (tromey@redhat.com)
063     * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
064     * @since 1.5
065     */
066    public interface Appendable
067    {
068    
069      /**
070       * Appends the Unicode character, c, to this <code>Appendable</code>
071       * object.
072       *
073       * @param c the character to append.
074       * @return a reference to this object.
075       * @throws IOException if an I/O error occurs.
076       */
077      Appendable append(char c)
078        throws IOException;
079    
080      /**
081       * Appends the specified sequence of Unicode characters to this
082       * <code>Appendable</code> object.  The entire sequence may not
083       * be appended, if constrained by the underlying implementation.
084       * For example, a buffer may reach its size limit before the entire
085       * sequence is appended.
086       *
087       * @param seq the character sequence to append.  If seq is null,
088       *        then the string "null" (the string representation of null)
089       *        is appended.
090       * @return a reference to this object.
091       * @throws IOException if an I/O error occurs.
092       */
093      Appendable append(CharSequence seq)
094        throws IOException;
095    
096      /**
097       * Appends the specified subsequence of Unicode characters to this
098       * <code>Appendable</code> object, starting and ending at the specified
099       * positions within the sequence.  The entire sequence may not
100       * be appended, if constrained by the underlying implementation.
101       * For example, a buffer may reach its size limit before the entire
102       * sequence is appended.  The behaviour of this method matches the
103       * behaviour of <code>append(seq.subSequence(start,end))</code> when
104       * the sequence is not null.
105       *
106       * @param seq the character sequence to append.  If seq is null,
107       *        then the string "null" (the string representation of null)
108       *        is appended.
109       * @param start the index of the first Unicode character to use from
110       *        the sequence.
111       * @param end the index of the last Unicode character to use from the
112       *        sequence.
113       * @return a reference to this object.
114       * @throws IOException if an I/O error occurs.
115       * @throws IndexOutOfBoundsException if either of the indices are negative,
116       *         the start index occurs after the end index, or the end index is
117       *         beyond the end of the sequence.
118       */
119      Appendable append(CharSequence seq, int start, int end)
120        throws IOException;
121    
122    }