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doctype html public "-//IETF//DTD HTML//EN">
0N/A<
body bgcolor="white">
0N/ADefines buffers, which are containers for data, and provides an overview of the
0N/A<
p> The central abstractions of the NIO APIs are: </
p>
0N/A <
li><
p> <
a href="#buffers"><
i>Buffers</
i></
a>, which are containers for data;
0N/A associated <
i>decoders</
i> and <
i>encoders</
i>, <
br> which translate between
0N/A bytes and Unicode characters; </
p></
li>
0N/A various types, which represent connections <
br> to entities capable of
0N/A performing I/O operations; and </
p></
li>
0N/A <
li><
p> <
i>Selectors</
i> and <
i>selection keys</
i>, which together with <
br>
0N/A <
i>selectable channels</
i> define a <
a 0N/A I/O</
a> facility. </
p></
li>
0N/A<
p> The <
tt>
java.nio</
tt> package defines the buffer classes, which are used
0N/Athroughout the NIO APIs. The charset API is defined in the {@link
0N/Aservice-provider (SPI) subpackage, the contents of which can be used to extend
0N/Athe platform's default implementations or to construct alternative
0N/A<
blockquote><
table cellspacing=1 cellpadding=0 summary="Description of the various buffers">
0N/A <
tr><
th><
p align="left">Buffers</
p></
th><
th><
p align="left">Description</
p></
th></
tr>
0N/A <
td>Position, limit, and capacity;
0N/A <
td>
Get/
put, compact, views; allocate, wrap</
td></
tr>
0N/A <
td>A byte buffer mapped to a file</
td></
tr>
0N/A <
td>
Get/
put, compact; allocate, wrap</
td></
tr>
0N/A <
td> ' '</
td></
tr>
0N/A <
td> ' '</
td></
tr>
0N/A <
td> ' '</
td></
tr>
0N/A <
td> ' '</
td></
tr>
0N/A <
td> ' '</
td></
tr>
0N/A <
td>Typesafe enumeration for byte orders</
td></
tr>
0N/A</
table></
blockquote>
0N/A<
p> A <
i>buffer</
i> is a container for a fixed amount of data of a specific
0N/Aprimitive type. In addition to its content a buffer has a <
i>position</
i>,
0N/Awhich is the index of the next element to be read or written, and a
0N/A<
i>limit</
i>, which is the index of the first element that should not be read
0N/Awell as methods for <
i>clearing</
i>, <
i>flipping</
i>, and <
i>rewinding</
i>, for
0N/A<
i>marking</
i> the current position, and for <
i>resetting</
i> the position to
0N/A<
p> There is a buffer class for each non-boolean primitive type. Each class
0N/Adefines a family of <
i>get</
i> and <
i>put</
i> methods for moving data out of
0N/Aand in to a buffer, methods for <
i>compacting</
i>, <
i>duplicating</
i>, and
0N/A<
i>slicing</
i> a buffer, and static methods for <
i>allocating</
i> a new buffer
0N/Aas well as for <
i>wrapping</
i> an existing array into a buffer.
0N/A<
p> Byte buffers are distinguished in that they can be used as the sources and
0N/Atargets of I/O operations. They also support several features not found in the
0N/Aother buffer classes:
0N/A <
i>direct</
i></
a> buffer, in which case the Java virtual machine will make a
0N/A best effort to perform native I/O operations directly upon it. </
p></
li>
0N/A <
li><
p> A byte buffer can be created by {@link
0N/A file directly into memory, in which case a few additional file-related
0N/A available. </
p></
li>
0N/A <
li><
p> A byte buffer provides access to its content as either a heterogeneous
0N/A of any non-boolean primitive type, in either big-endian or little-endian <
a 0N/A<
p> Unless otherwise noted, passing a <
tt>null</
tt> argument to a constructor
0N/Aor method in any class or interface in this package will cause a {@link
0N/A@author Mark Reinhold
0N/A@author JSR-51 Expert Group