/*

 * Copyright 2003-2004 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

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;

}