| /* | 
 |  * Copyright (c) 2000, 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 | 
 |  * or visit www.oracle.com if you need additional information or have any | 
 |  * questions. | 
 |  */ | 
 |  | 
 | /** | 
 |  * Defines buffers, which are containers for data, and provides an overview of the | 
 |  * other NIO packages. | 
 |  * | 
 |  * | 
 |  * <p> The central abstractions of the NIO APIs are: </p> | 
 |  * | 
 |  * <ul> | 
 |  * | 
 |  *   <li><p> <a href="#buffers"><i>Buffers</i></a>, which are containers for data; | 
 |  *   </p></li> | 
 |  * | 
 |  *   <li><p> <a href="charset/package-summary.html"><i>Charsets</i></a> and their | 
 |  *   associated <i>decoders</i> and <i>encoders</i>, <br> which translate between | 
 |  *   bytes and Unicode characters; </p></li> | 
 |  * | 
 |  *   <li><p> <a href="channels/package-summary.html"><i>Channels</i></a> of | 
 |  *   various types, which represent connections <br> to entities capable of | 
 |  *   performing I/O operations; and </p></li> | 
 |  * | 
 |  *   <li><p> <i>Selectors</i> and <i>selection keys</i>, which together with <br> | 
 |  *   <i>selectable channels</i> define a <a | 
 |  *   href="channels/package-summary.html#multiplex">multiplexed, non-blocking <br> | 
 |  *   I/O</a> facility.  </p></li> | 
 |  * | 
 |  * </ul> | 
 |  * | 
 |  * <p> The <tt>java.nio</tt> package defines the buffer classes, which are used | 
 |  * throughout the NIO APIs.  The charset API is defined in the {@link | 
 |  * java.nio.charset} package, and the channel and selector APIs are defined in the | 
 |  * {@link java.nio.channels} package.  Each of these subpackages has its own | 
 |  * service-provider (SPI) subpackage, the contents of which can be used to extend | 
 |  * the platform's default implementations or to construct alternative | 
 |  * implementations. | 
 |  * | 
 |  * | 
 |  * <a name="buffers"> | 
 |  * | 
 |  * <blockquote><table cellspacing=1 cellpadding=0 summary="Description of the various buffers"> | 
 |  *   <tr><th><p align="left">Buffers</p></th><th><p align="left">Description</p></th></tr> | 
 |  *   <tr><td valign=top><tt>{@link java.nio.Buffer}</tt></td> | 
 |  *       <td>Position, limit, and capacity; | 
 |  *           <br>clear, flip, rewind, and mark/reset</td></tr> | 
 |  *   <tr><td valign=top><tt>  {@link java.nio.ByteBuffer}</tt></td> | 
 |  *       <td>Get/put, compact, views; allocate, wrap</td></tr> | 
 |  *   <tr><td valign=top><tt>    {@link java.nio.MappedByteBuffer}  </tt></td> | 
 |  *       <td>A byte buffer mapped to a file</td></tr> | 
 |  *   <tr><td valign=top><tt>  {@link java.nio.CharBuffer}</tt></td> | 
 |  *       <td>Get/put, compact; allocate, wrap</td></tr> | 
 |  *   <tr><td valign=top><tt>  {@link java.nio.DoubleBuffer}</tt></td> | 
 |  *       <td>    ' '</td></tr> | 
 |  *   <tr><td valign=top><tt>  {@link java.nio.FloatBuffer}</tt></td> | 
 |  *       <td>    ' '</td></tr> | 
 |  *   <tr><td valign=top><tt>  {@link java.nio.IntBuffer}</tt></td> | 
 |  *       <td>    ' '</td></tr> | 
 |  *   <tr><td valign=top><tt>  {@link java.nio.LongBuffer}</tt></td> | 
 |  *       <td>    ' '</td></tr> | 
 |  *   <tr><td valign=top><tt>  {@link java.nio.ShortBuffer}</tt></td> | 
 |  *       <td>    ' '</td></tr> | 
 |  *   <tr><td valign=top><tt>{@link java.nio.ByteOrder}</tt></td> | 
 |  *       <td>Typesafe enumeration for byte orders</td></tr> | 
 |  * </table></blockquote> | 
 |  * | 
 |  * <p> A <i>buffer</i> is a container for a fixed amount of data of a specific | 
 |  * primitive type.  In addition to its content a buffer has a <i>position</i>, | 
 |  * which is the index of the next element to be read or written, and a | 
 |  * <i>limit</i>, which is the index of the first element that should not be read | 
 |  * or written.  The base {@link java.nio.Buffer} class defines these properties as | 
 |  * well as methods for <i>clearing</i>, <i>flipping</i>, and <i>rewinding</i>, for | 
 |  * <i>marking</i> the current position, and for <i>resetting</i> the position to | 
 |  * the previous mark. | 
 |  * | 
 |  * <p> There is a buffer class for each non-boolean primitive type.  Each class | 
 |  * defines a family of <i>get</i> and <i>put</i> methods for moving data out of | 
 |  * and in to a buffer, methods for <i>compacting</i>, <i>duplicating</i>, and | 
 |  * <i>slicing</i> a buffer, and static methods for <i>allocating</i> a new buffer | 
 |  * as well as for <i>wrapping</i> an existing array into a buffer. | 
 |  * | 
 |  * <p> Byte buffers are distinguished in that they can be used as the sources and | 
 |  * targets of I/O operations.  They also support several features not found in the | 
 |  * other buffer classes: | 
 |  * | 
 |  * <ul> | 
 |  * | 
 |  *   <li><p> A byte buffer can be allocated as a <a href="ByteBuffer.html#direct"> | 
 |  *   <i>direct</i></a> buffer, in which case the Java virtual machine will make a | 
 |  *   best effort to perform native I/O operations directly upon it.  </p></li> | 
 |  * | 
 |  *   <li><p> A byte buffer can be created by {@link | 
 |  *   java.nio.channels.FileChannel#map </code><i>mapping</i><code>} a region of a | 
 |  *   file directly into memory, in which case a few additional file-related | 
 |  *   operations defined in the {@link java.nio.MappedByteBuffer} class are | 
 |  *   available.  </p></li> | 
 |  * | 
 |  *   <li><p> A byte buffer provides access to its content as either a heterogeneous | 
 |  *   or homogeneous sequence of <a href="ByteBuffer.html#bin">binary data</i></a> | 
 |  *   of any non-boolean primitive type, in either big-endian or little-endian <a | 
 |  *   href="ByteOrder.html">byte order</a>.  </p></li> | 
 |  * | 
 |  * </ul> | 
 |  * | 
 |  * <p> Unless otherwise noted, passing a <tt>null</tt> argument to a constructor | 
 |  * or method in any class or interface in this package will cause a {@link | 
 |  * java.lang.NullPointerException NullPointerException} to be thrown. | 
 |  * | 
 |  * @since 1.4 | 
 |  * @author Mark Reinhold | 
 |  * @author JSR-51 Expert Group | 
 |  */ | 
 |  | 
 | package java.nio; |