--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/java.base/share/classes/java/nio/channels/SeekableByteChannel.java Sun Aug 17 15:54:13 2014 +0100
@@ -0,0 +1,168 @@
+/*
+ * Copyright (c) 2007, 2011, 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.nio.ByteBuffer;
+import java.io.IOException;
+
+/**
+ * A byte channel that maintains a current <i>position</i> and allows the
+ * position to be changed.
+ *
+ * <p> A seekable byte channel is connected to an entity, typically a file,
+ * that contains a variable-length sequence of bytes that can be read and
+ * written. The current position can be {@link #position() <i>queried</i>} and
+ * {@link #position(long) <i>modified</i>}. The channel also provides access to
+ * the current <i>size</i> of the entity to which the channel is connected. The
+ * size increases when bytes are written beyond its current size; the size
+ * decreases when it is {@link #truncate <i>truncated</i>}.
+ *
+ * <p> The {@link #position(long) position} and {@link #truncate truncate} methods
+ * which do not otherwise have a value to return are specified to return the
+ * channel upon which they are invoked. This allows method invocations to be
+ * chained. Implementations of this interface should specialize the return type
+ * so that method invocations on the implementation class can be chained.
+ *
+ * @since 1.7
+ * @see java.nio.file.Files#newByteChannel
+ */
+
+public interface SeekableByteChannel
+ extends ByteChannel
+{
+ /**
+ * Reads a sequence of bytes from this channel into the given buffer.
+ *
+ * <p> Bytes are read starting at this channel's current position, and
+ * then the position is updated with the number of bytes actually read.
+ * Otherwise this method behaves exactly as specified in the {@link
+ * ReadableByteChannel} interface.
+ */
+ @Override
+ int read(ByteBuffer dst) throws IOException;
+
+ /**
+ * Writes a sequence of bytes to this channel from the given buffer.
+ *
+ * <p> Bytes are written starting at this channel's current position, unless
+ * the channel is connected to an entity such as a file that is opened with
+ * the {@link java.nio.file.StandardOpenOption#APPEND APPEND} option, in
+ * which case the position is first advanced to the end. The entity to which
+ * the channel is connected is grown, if necessary, to accommodate the
+ * written bytes, and then the position is updated with the number of bytes
+ * actually written. Otherwise this method behaves exactly as specified by
+ * the {@link WritableByteChannel} interface.
+ */
+ @Override
+ int write(ByteBuffer src) throws IOException;
+
+ /**
+ * Returns this channel's position.
+ *
+ * @return This channel's position,
+ * a non-negative integer counting the number of bytes
+ * from the beginning of the entity to the current position
+ *
+ * @throws ClosedChannelException
+ * If this channel is closed
+ * @throws IOException
+ * If some other I/O error occurs
+ */
+ long position() throws IOException;
+
+ /**
+ * Sets this channel's position.
+ *
+ * <p> Setting the position to a value that is greater than the current size
+ * is legal but does not change the size of the entity. A later attempt to
+ * read bytes at such a position will immediately return an end-of-file
+ * indication. A later attempt to write bytes at such a position will cause
+ * the entity to grow to accommodate the new bytes; the values of any bytes
+ * between the previous end-of-file and the newly-written bytes are
+ * unspecified.
+ *
+ * <p> Setting the channel's position is not recommended when connected to
+ * an entity, typically a file, that is opened with the {@link
+ * java.nio.file.StandardOpenOption#APPEND APPEND} option. When opened for
+ * append, the position is first advanced to the end before writing.
+ *
+ * @param newPosition
+ * The new position, a non-negative integer counting
+ * the number of bytes from the beginning of the entity
+ *
+ * @return This channel
+ *
+ * @throws ClosedChannelException
+ * If this channel is closed
+ * @throws IllegalArgumentException
+ * If the new position is negative
+ * @throws IOException
+ * If some other I/O error occurs
+ */
+ SeekableByteChannel position(long newPosition) throws IOException;
+
+ /**
+ * Returns the current size of entity to which this channel is connected.
+ *
+ * @return The current size, measured in bytes
+ *
+ * @throws ClosedChannelException
+ * If this channel is closed
+ * @throws IOException
+ * If some other I/O error occurs
+ */
+ long size() throws IOException;
+
+ /**
+ * Truncates the entity, to which this channel is connected, to the given
+ * size.
+ *
+ * <p> If the given size is less than the current size then the entity is
+ * truncated, discarding any bytes beyond the new end. If the given size is
+ * greater than or equal to the current size then the entity is not modified.
+ * In either case, if the current position is greater than the given size
+ * then it is set to that size.
+ *
+ * <p> An implementation of this interface may prohibit truncation when
+ * connected to an entity, typically a file, opened with the {@link
+ * java.nio.file.StandardOpenOption#APPEND APPEND} option.
+ *
+ * @param size
+ * The new size, a non-negative byte count
+ *
+ * @return This channel
+ *
+ * @throws NonWritableChannelException
+ * If this channel was not opened for writing
+ * @throws ClosedChannelException
+ * If this channel is closed
+ * @throws IllegalArgumentException
+ * If the new size is negative
+ * @throws IOException
+ * If some other I/O error occurs
+ */
+ SeekableByteChannel truncate(long size) throws IOException;
+}