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package java.lang;

import java.io.IOException;


An object to which char sequences and values can be appended.  The
Appendable interface must be implemented by any class whose instances are intended to receive formatted output from a Formatter. 
 The characters to be appended should be valid Unicode characters as
described in Unicode Character
Representation.  Note that supplementary characters may be composed of
multiple 16-bit char values.

 Appendables are not necessarily safe for multithreaded access.  Thread
safety is the responsibility of classes that extend and implement this
interface.

 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
/**
 * 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 Appendable.

 Depending on which class implements the character sequence
csq, the entire sequence may not be appended.  For
instance, if csq is a CharBuffer then the subsequence to append is defined by the buffer's position and limit. 
Params:
  • csq – 
        The character sequence to append.  If csq is
        null, then the four characters "null" are
        appended to this Appendable.
Throws:
Returns: A reference to this 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
Appendable.

 An invocation of this method of the form out.append(csq, start,
end) when csq is not null, behaves in
exactly the same way as the invocation

    out.append(csq.subSequence(start, end)) 


Params:
  • csq – 
        The character sequence from which a subsequence will be
        appended.  If csq is null, then characters
        will be appended as if csq contained the four
        characters "null".
  • start – 
        The index of the first character in the subsequence
  • end – 
        The index of the character following the last character in the
        subsequence
Throws:
Returns: A reference to this Appendable
/**
     * 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 Appendable.

Params:
  • c – 
        The character to append
Throws:
Returns: A reference to this Appendable
/**
     * 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;
}