/*

 * 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 {@code char} sequences and values can be appended.  The

 * {@code Appendable} 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 {@code char} 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 {@code Appendable}.

     *

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

     * {@code csq}, the entire sequence may not be appended.  For

     * instance, if {@code csq} 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 {@code csq} is

     *         {@code null}, then the four characters {@code "null"} are

     *         appended to this Appendable.

     *

     * @return  A reference to this {@code Appendable}

     *

     * @throws  IOException

     *          If an I/O error occurs

     */

    Appendable append(CharSequence csq) throws IOException;

    /**

     * Appends a subsequence of the specified character sequence to this

     * {@code Appendable}.

     *

     * <p> An invocation of this method of the form {@code out.append(csq, start, end)}

     * when {@code csq} is not {@code null}, 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 {@code csq} is {@code null}, then characters

     *         will be appended as if {@code csq} contained the four

     *         characters {@code "null"}.

     *

     * @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 {@code Appendable}

     *

     * @throws  IndexOutOfBoundsException

     *          If {@code start} or {@code end} are negative, {@code start}

     *          is greater than {@code end}, or {@code end} is greater than

     *          {@code csq.length()}

     *

     * @throws  IOException

     *          If an I/O error occurs

     */

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

    /**

     * Appends the specified character to this {@code Appendable}.

     *

     * @param  c

     *         The character to append

     *

     * @return  A reference to this {@code Appendable}

     *

     * @throws  IOException

     *          If an I/O error occurs

     */

    Appendable append(char c) throws IOException;

}