Class JimfsFileChannel

java.lang.Object

java.nio.channels.spi.AbstractInterruptibleChannel

java.nio.channels.FileChannel

com.google.common.jimfs.JimfsFileChannel

All Implemented Interfaces:

Closeable, AutoCloseable, ByteChannel, Channel, GatheringByteChannel, InterruptibleChannel, ReadableByteChannel, ScatteringByteChannel, SeekableByteChannel, WritableByteChannel

final class JimfsFileChannel
extends FileChannel

A FileChannel implementation that reads and writes to a RegularFile object. The read and write methods and other methods that read or change the position of the channel are locked because the ReadableByteChannel and WritableByteChannel interfaces specify that the read and write methods block when another thread is currently doing a read or write operation.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static final class	JimfsFileChannel.FakeFileLock	A file lock that does nothing, since only one JVM process has access to this file system.

Nested classes/interfaces inherited from class FileChannel

FileChannel.MapMode

Field Summary

Fields

Modifier and Type	Field	Description
private final boolean	append
private final Set<Thread>	blockingThreads	Set of threads that are currently doing an interruptible blocking operation; that is, doing something that requires acquiring the file's lock.
private final RegularFile	file
private final FileSystemState	fileSystemState
private long	position
private final boolean	read
private final boolean	write

Constructor Summary

Constructors

Constructor	Description
JimfsFileChannel(RegularFile file, Set<OpenOption> options, FileSystemState fileSystemState)

Method Summary

Modifier and Type	Method	Description
AsynchronousFileChannel	asAsynchronousFileChannel(ExecutorService executor)	Returns an AsynchronousFileChannel view of this channel using the given executor for asynchronous operations.
private boolean	beginBlocking()	Begins a blocking operation, making the operation interruptible.
private void	checkLockArguments(long position, long size, boolean shared)
(package private) void	checkOpen()
(package private) void	checkReadable()
(package private) void	checkWritable()
private void	endBlocking(boolean completed)	Ends a blocking operation, throwing an exception if the thread was interrupted while blocking or if the channel was closed from another thread.
void	force(boolean metaData)
protected void	implCloseChannel()
FileLock	lock(long position, long size, boolean shared)
MappedByteBuffer	map(FileChannel.MapMode mode, long position, long size)
long	position()
FileChannel	position(long newPosition)
int	read(ByteBuffer dst)
long	read(ByteBuffer[] dsts, int offset, int length)
int	read(ByteBuffer dst, long position)
long	size()
long	transferFrom(ReadableByteChannel src, long position, long count)
long	transferTo(long position, long count, WritableByteChannel target)
FileChannel	truncate(long size)
FileLock	tryLock(long position, long size, boolean shared)
int	write(ByteBuffer src)
long	write(ByteBuffer[] srcs, int offset, int length)
int	write(ByteBuffer src, long position)

Methods inherited from class FileChannel

lock, map, open, open, read, tryLock, write

Methods inherited from class AbstractInterruptibleChannel

begin, close, end, isOpen

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface Channel

isOpen

Field Details

blockingThreads

private final Set<Thread> blockingThreads

Set of threads that are currently doing an interruptible blocking operation; that is, doing something that requires acquiring the file's lock. These threads must be interrupted if the channel is closed by another thread.

file

private final RegularFile file

fileSystemState

private final FileSystemState fileSystemState

read

private final boolean read

write

private final boolean write

append

private final boolean append

position

private long position

Constructor Details

JimfsFileChannel

public JimfsFileChannel(RegularFile file,
 Set<OpenOption> options,
 FileSystemState fileSystemState)

Method Details

asAsynchronousFileChannel

public AsynchronousFileChannel asAsynchronousFileChannel(ExecutorService executor)

Returns an AsynchronousFileChannel view of this channel using the given executor for asynchronous operations.

checkReadable

void checkReadable()

checkWritable

void checkWritable()

checkOpen

void checkOpen()
        throws ClosedChannelException

Throws:

ClosedChannelException

beginBlocking

private boolean beginBlocking()

Begins a blocking operation, making the operation interruptible. Returns true if the channel was open and the thread was added as a blocking thread; returns false if the channel was closed.

endBlocking

private void endBlocking(boolean completed)
                  throws AsynchronousCloseException

Ends a blocking operation, throwing an exception if the thread was interrupted while blocking or if the channel was closed from another thread.

Throws:

AsynchronousCloseException

read

public int read(ByteBuffer dst)
         throws IOException

Specified by:

read in interface ReadableByteChannel

Specified by:

read in interface SeekableByteChannel

Specified by:

read in class FileChannel

Throws:

IOException

read

public long read(ByteBuffer[] dsts,
 int offset,
 int length)
          throws IOException

Specified by:

read in interface ScatteringByteChannel

Specified by:

read in class FileChannel

Throws:

IOException

read

public int read(ByteBuffer dst,
 long position)
         throws IOException

Specified by:

read in class FileChannel

Throws:

IOException

write

public int write(ByteBuffer src)
          throws IOException

Specified by:

write in interface SeekableByteChannel

Specified by:

write in interface WritableByteChannel

Specified by:

write in class FileChannel

Throws:

IOException

write

public long write(ByteBuffer[] srcs,
 int offset,
 int length)
           throws IOException

Specified by:

write in interface GatheringByteChannel

Specified by:

write in class FileChannel

Throws:

IOException

write

public int write(ByteBuffer src,
 long position)
          throws IOException

Specified by:

write in class FileChannel

Throws:

IOException

position

public long position()
              throws IOException

Specified by:

position in interface SeekableByteChannel

Specified by:

position in class FileChannel

Throws:

IOException

position

@CanIgnoreReturnValue
public FileChannel position(long newPosition)
                     throws IOException

Specified by:

position in interface SeekableByteChannel

Specified by:

position in class FileChannel

Throws:

IOException

size

public long size()
          throws IOException

Specified by:

size in interface SeekableByteChannel

Specified by:

size in class FileChannel

Throws:

IOException

truncate

@CanIgnoreReturnValue
public FileChannel truncate(long size)
                     throws IOException

Specified by:

truncate in interface SeekableByteChannel

Specified by:

truncate in class FileChannel

Throws:

IOException

force

public void force(boolean metaData)
           throws IOException

Specified by:

force in class FileChannel

Throws:

IOException

transferTo

public long transferTo(long position,
 long count,
 WritableByteChannel target)
                throws IOException

Specified by:

transferTo in class FileChannel

Throws:

IOException

transferFrom

public long transferFrom(ReadableByteChannel src,
 long position,
 long count)
                  throws IOException

Specified by:

transferFrom in class FileChannel

Throws:

IOException

map

public MappedByteBuffer map(FileChannel.MapMode mode,
 long position,
 long size)
                     throws IOException

Specified by:

map in class FileChannel

Throws:

IOException

lock

public FileLock lock(long position,
 long size,
 boolean shared)
              throws IOException

Specified by:

lock in class FileChannel

Throws:

IOException

tryLock

public FileLock tryLock(long position,
 long size,
 boolean shared)
                 throws IOException

Specified by:

tryLock in class FileChannel

Throws:

IOException

checkLockArguments

private void checkLockArguments(long position,
 long size,
 boolean shared)
                         throws IOException

Throws:

IOException

implCloseChannel

protected void implCloseChannel()

Specified by:

implCloseChannel in class AbstractInterruptibleChannel