/*

  * Copyright (c) 2003, 2004, 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

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 package java.lang;

 import java.io.IOException;

 /**

  * An object to which <tt>char</tt> sequences and values can be appended.  The

  * <tt>Appendable</tt> interface must be implemented by any class whose

  * instances are intended to receive formatted output from a {@link

  * java.util.Formatter}.

  *

  * <p> The characters to be appended should be valid Unicode characters as

  * described in <a href="Character.html#unicode">Unicode Character

  * Representation</a>.  Note that supplementary characters may be composed of

  * multiple 16-bit <tt>char</tt> values.

  *

  * <p> Appendables are not necessarily safe for multithreaded access.  Thread

  * safety is the responsibility of classes that extend and implement this

  * interface.

  *

  * <p> Since this interface may be implemented by existing classes

  * with different styles of error handling there is no guarantee that

  * errors will be propagated to the invoker.

  *

  * @since 1.5

  */

 public interface Appendable {

     /**

      * Appends the specified character sequence to this <tt>Appendable</tt>.

      *

      * <p> Depending on which class implements the character sequence

      * <tt>csq</tt>, the entire sequence may not be appended.  For

      * instance, if <tt>csq</tt> is a {@link java.nio.CharBuffer} then

      * the subsequence to append is defined by the buffer's position and limit.

      *

      * @param  csq

      *         The character sequence to append.  If <tt>csq</tt> is

      *         <tt>null</tt>, then the four characters <tt>"null"</tt> are

      *         appended to this Appendable.

      *

      * @return  A reference to this <tt>Appendable</tt>

      *

      * @throws  IOException

      *          If an I/O error occurs

      */

     Appendable append(CharSequence csq) throws IOException;

     /**

      * Appends a subsequence of the specified character sequence to this

      * <tt>Appendable</tt>.

      *

      * <p> An invocation of this method of the form <tt>out.append(csq, start,

      * end)</tt> when <tt>csq</tt> is not <tt>null</tt>, behaves in

      * exactly the same way as the invocation

      *

      * <pre>

      *     out.append(csq.subSequence(start, end)) </pre>

      *

      * @param  csq

      *         The character sequence from which a subsequence will be

      *         appended.  If <tt>csq</tt> is <tt>null</tt>, then characters

      *         will be appended as if <tt>csq</tt> contained the four

      *         characters <tt>"null"</tt>.

      *

      * @param  start

      *         The index of the first character in the subsequence

      *

      * @param  end

      *         The index of the character following the last character in the

      *         subsequence

      *

      * @return  A reference to this <tt>Appendable</tt>

      *

      * @throws  IndexOutOfBoundsException

      *          If <tt>start</tt> or <tt>end</tt> are negative, <tt>start</tt>

      *          is greater than <tt>end</tt>, or <tt>end</tt> is greater than

      *          <tt>csq.length()</tt>

      *

      * @throws  IOException

      *          If an I/O error occurs

      */

     Appendable append(CharSequence csq, int start, int end) throws IOException;

     /**

      * Appends the specified character to this <tt>Appendable</tt>.

      *

      * @param  c

      *         The character to append

      *

      * @return  A reference to this <tt>Appendable</tt>

      *

      * @throws  IOException

      *          If an I/O error occurs

      */

     Appendable append(char c) throws IOException;

 }