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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libjava/classpath/java/nio/channels/FileLock.java | |
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Diffstat (limited to 'libjava/classpath/java/nio/channels/FileLock.java')
-rw-r--r-- | libjava/classpath/java/nio/channels/FileLock.java | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/libjava/classpath/java/nio/channels/FileLock.java b/libjava/classpath/java/nio/channels/FileLock.java new file mode 100644 index 000000000..78210b34d --- /dev/null +++ b/libjava/classpath/java/nio/channels/FileLock.java @@ -0,0 +1,151 @@ +/* FileLock.java -- + Copyright (C) 2002, 2005 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + +package java.nio.channels; + +import gnu.java.lang.CPStringBuilder; + +import java.io.IOException; + +/** + * @since 1.4 + */ +public abstract class FileLock +{ + private final FileChannel channel; + private final long position; + private final long size; + private final boolean shared; + + /** + * Initializes the file lock. + * + * @exception IllegalArgumentException If the preconditions on the parameters do not hold + */ + protected FileLock(FileChannel channel, long position, long size, + boolean shared) + { + if (position < 0 || size < 0) + throw new IllegalArgumentException(); + + this.channel = channel; + this.position = position; + this.size = size; + this.shared = shared; + } + + /** + * Tells whether or not this lock is valid. + */ + public abstract boolean isValid(); + + /** + * Releases this lock. + * + * @exception IOException If an error occurs + * @exception ClosedChannelException If the locked channel is no longer open. + */ + public abstract void release() throws IOException; + + /** + * Returns the file channel upon whose file this lock is held. + */ + public final FileChannel channel() + { + return channel; + } + + /** + * Tells whether this lock is shared. + */ + public final boolean isShared() + { + return shared; + } + + /** + * Tells whether or not this lock overlaps the given lock range. + */ + public final boolean overlaps(long position, long size) + { + if (position > this.position + this.size) + return false; + + if (position + size < this.position) + return false; + + return true; + } + + /** + * Returns the position within the file of the first byte of the + * locked region. + */ + public final long position() + { + return position; + } + + /** + * Returns the size of the locked region in bytes. + */ + public final long size() + { + return size; + } + + /** + * Returns a string describing the range, type, and validity of this lock. + */ + public final String toString() + { + CPStringBuilder buf = new CPStringBuilder(getClass().getName()); + buf.append("["); + buf.append(position); + buf.append(":"); + buf.append(size); + if (shared) + buf.append(" shared"); + else + buf.append(" exclusive"); + if (isValid()) + buf.append(" valid]"); + else + buf.append(" invalid]"); + return buf.toString(); + } +} |