| /* |
| * Copyright (c) 2000, 2001, 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. |
| */ |
| |
| package java.nio.channels; |
| |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| |
| |
| /** |
| * A channel that can read bytes. |
| * |
| * <p> Only one read operation upon a readable channel may be in progress at |
| * any given time. If one thread initiates a read operation upon a channel |
| * then any other thread that attempts to initiate another read operation will |
| * block until the first operation is complete. Whether or not other kinds of |
| * I/O operations may proceed concurrently with a read operation depends upon |
| * the type of the channel. </p> |
| * |
| * |
| * @author Mark Reinhold |
| * @author JSR-51 Expert Group |
| * @since 1.4 |
| */ |
| |
| public interface ReadableByteChannel extends Channel { |
| |
| /** |
| * Reads a sequence of bytes from this channel into the given buffer. |
| * |
| * <p> An attempt is made to read up to <i>r</i> bytes from the channel, |
| * where <i>r</i> is the number of bytes remaining in the buffer, that is, |
| * <tt>dst.remaining()</tt>, at the moment this method is invoked. |
| * |
| * <p> Suppose that a byte sequence of length <i>n</i> is read, where |
| * <tt>0</tt> <tt><=</tt> <i>n</i> <tt><=</tt> <i>r</i>. |
| * This byte sequence will be transferred into the buffer so that the first |
| * byte in the sequence is at index <i>p</i> and the last byte is at index |
| * <i>p</i> <tt>+</tt> <i>n</i> <tt>-</tt> <tt>1</tt>, |
| * where <i>p</i> is the buffer's position at the moment this method is |
| * invoked. Upon return the buffer's position will be equal to |
| * <i>p</i> <tt>+</tt> <i>n</i>; its limit will not have changed. |
| * |
| * <p> A read operation might not fill the buffer, and in fact it might not |
| * read any bytes at all. Whether or not it does so depends upon the |
| * nature and state of the channel. A socket channel in non-blocking mode, |
| * for example, cannot read any more bytes than are immediately available |
| * from the socket's input buffer; similarly, a file channel cannot read |
| * any more bytes than remain in the file. It is guaranteed, however, that |
| * if a channel is in blocking mode and there is at least one byte |
| * remaining in the buffer then this method will block until at least one |
| * byte is read. |
| * |
| * <p> This method may be invoked at any time. If another thread has |
| * already initiated a read operation upon this channel, however, then an |
| * invocation of this method will block until the first operation is |
| * complete. </p> |
| * |
| * @param dst |
| * The buffer into which bytes are to be transferred |
| * |
| * @return The number of bytes read, possibly zero, or <tt>-1</tt> if the |
| * channel has reached end-of-stream |
| * |
| * @throws NonReadableChannelException |
| * If this channel was not opened for reading |
| * |
| * @throws ClosedChannelException |
| * If this channel is closed |
| * |
| * @throws AsynchronousCloseException |
| * If another thread closes this channel |
| * while the read operation is in progress |
| * |
| * @throws ClosedByInterruptException |
| * If another thread interrupts the current thread |
| * while the read operation is in progress, thereby |
| * closing the channel and setting the current thread's |
| * interrupt status |
| * |
| * @throws IOException |
| * If some other I/O error occurs |
| */ |
| public int read(ByteBuffer dst) throws IOException; |
| |
| } |
