e3b6a47f66
2003-02-11 Michael Koch <konqueror@gmx.de> * gnu/java/nio/FileLockImpl.java, java/nio/channels/FileLock.java: New files. From-SVN: r62681
138 lines
3.6 KiB
Java
138 lines
3.6 KiB
Java
/* FileLock.java --
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Copyright (C) 2002 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.nio.channels;
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import java.io.IOException;
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/**
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* @since 1.4
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*/
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public abstract class FileLock
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{
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FileChannel channel;
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long position;
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long size;
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boolean shared;
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/**
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* Initializes the file lock.
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*
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* @exception IllegalArgumentException If the preconditions on the parameters do not hold
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*/
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protected FileLock (FileChannel channel, long position, long size,
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boolean shared)
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{
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if (position < 0 ||
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size < 0)
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throw new IllegalArgumentException ();
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this.channel = channel;
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this.position = position;
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this.size = size;
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this.shared = shared;
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}
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/**
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* Tells whether or not this lock is valid.
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*/
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public abstract boolean isValid();
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/**
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* Releases this lock.
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*
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* @exception IOException If an error occurs
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* @exception ClosedChannelException If the locked channel is no longer open.
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*/
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public abstract void release () throws IOException;
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/**
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* Returns the file channel upon whose file this lock is held.
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*/
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public final FileChannel channel ()
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{
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return channel;
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}
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/**
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* Tells whether this lock is shared.
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*/
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public final boolean isShared ()
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{
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return shared;
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}
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/**
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* Tells whether or not this lock overlaps the given lock range.
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*/
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public final boolean overlaps (long position, long size)
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{
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if (position > this.position +this.size)
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return false;
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if (position + size < this.position)
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return false;
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return true;
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}
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/**
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* Returns the position within the file of the first byte of the
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* locked region.
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*/
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public final long position ()
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{
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return position;
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}
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/**
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* Returns the size of the locked region in bytes.
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*/
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public final long size ()
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{
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return size;
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}
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/**
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* Returns a string describing the range, type, and validity of this lock.
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*/
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public final String toString ()
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{
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return "file-lock:pos=" + position + "size=" + size;
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}
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}
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