io.atomix.storage.buffer

Class FileBuffer

java.lang.Object

io.atomix.storage.buffer.AbstractBuffer

io.atomix.storage.buffer.FileBuffer

All Implemented Interfaces:

Buffer, BufferInput<Buffer>, BufferOutput<Buffer>, BytesInput<Buffer>, BytesOutput<Buffer>, io.atomix.utils.concurrent.ReferenceCounted<Buffer>, AutoCloseable

public class FileBuffer
extends AbstractBuffer

File buffer.

File buffers wrap a simple RandomAccessFile instance to provide random access to a file on local disk. All operations are delegated directly to the RandomAccessFile interface, and limitations are dependent on the semantics of the underlying file.

Author:

Jordan Halterman

Method Summary

Modifier and Type	Method and Description
static FileBuffer	allocate(File file) Allocates a file buffer of unlimited capacity.
static FileBuffer	allocate(File file, int initialCapacity) Allocates a file buffer with the given initial capacity.
static FileBuffer	allocate(File file, int initialCapacity, int maxCapacity) Allocates a file buffer.
static FileBuffer	allocate(File file, String mode, int initialCapacity, int maxCapacity) Allocates a file buffer.
void	delete() Deletes the underlying file.
FileBuffer	duplicate() Returns a duplicate of the buffer.
FileBuffer	duplicate(String mode) Duplicates the buffer using the given mode.
File	file() Returns the underlying file object.
MappedBuffer	map(int size) Maps a portion of the underlying file into memory in FileChannel.MapMode#READ_WRITE mode starting at the current position up to the given count.
MappedBuffer	map(int size, FileChannel.MapMode mode) Maps a portion of the underlying file into memory starting at the current position up to the given count.
MappedBuffer	map(int offset, int size) Maps a portion of the underlying file into memory in FileChannel.MapMode#READ_WRITE mode starting at the given offset up to the given count.
MappedBuffer	map(int offset, int size, FileChannel.MapMode mode) Maps a portion of the underlying file into memory starting at the given offset up to the given count.

Methods inherited from class io.atomix.storage.buffer.AbstractBuffer

acquire, asReadOnlyBuffer, bytes, capacity, capacity, clear, close, compact, flip, flush, hasRemaining, isDirect, isFile, isReadOnly, limit, limit, mark, maxCapacity, offset, order, order, position, position, read, read, read, read, read, read, read, readBoolean, readBoolean, readByte, readByte, readChar, readChar, readDouble, readDouble, readFloat, readFloat, readInt, readInt, readLong, readLong, readMedium, readMedium, readShort, readShort, readString, readString, readString, readString, readUnsignedByte, readUnsignedByte, readUnsignedInt, readUnsignedInt, readUnsignedMedium, readUnsignedMedium, readUnsignedShort, readUnsignedShort, readUTF8, readUTF8, references, release, remaining, reset, rewind, skip, slice, slice, slice, write, write, write, write, write, write, write, writeBoolean, writeBoolean, writeByte, writeByte, writeChar, writeChar, writeDouble, writeDouble, writeFloat, writeFloat, writeInt, writeInt, writeLong, writeLong, writeMedium, writeMedium, writeShort, writeShort, writeString, writeString, writeString, writeString, writeUnsignedByte, writeUnsignedByte, writeUnsignedInt, writeUnsignedInt, writeUnsignedMedium, writeUnsignedMedium, writeUnsignedShort, writeUnsignedShort, writeUTF8, writeUTF8, zero, zero, zero

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.atomix.storage.buffer.Buffer

array, hasArray

Methods inherited from interface io.atomix.storage.buffer.BufferInput

readBytes

Methods inherited from interface io.atomix.storage.buffer.BufferOutput

writeBytes

Method Detail

allocate

public static FileBuffer allocate(File file)

Allocates a file buffer of unlimited capacity.

The buffer will initially be allocated with 4096 bytes. As bytes are written to the resulting buffer and the original capacity is reached, the buffer's capacity will double.

Parameters:

file - The file to allocate.

Returns:

The allocated buffer.

See Also:

allocate(File, int), allocate(File, int, int), allocate(File, String, int, int)

allocate

public static FileBuffer allocate(File file,
                                  int initialCapacity)

Allocates a file buffer with the given initial capacity.

If the underlying file is empty, the file count will expand dynamically as bytes are written to the file. The underlying FileBytes will be initialized to the nearest power of 2.

Parameters:

file - The file to allocate.

initialCapacity - The initial capacity of the bytes to allocate.

Returns:

The allocated buffer.

See Also:

allocate(File), allocate(File, int, int), allocate(File, String, int, int)

allocate

public static FileBuffer allocate(File file,
                                  int initialCapacity,
                                  int maxCapacity)

Allocates a file buffer.

The underlying RandomAccessFile will be created in rw mode by default. The resulting buffer will be initialized with a capacity of initialCapacity. The underlying FileBytes will be initialized to the nearest power of 2. As bytes are written to the file the buffer's capacity will double up to maxCapacity.

Parameters:

file - The file to allocate.

initialCapacity - The initial capacity of the buffer.

maxCapacity - The maximum allowed capacity of the buffer.

Returns:

The allocated buffer.

See Also:

allocate(File), allocate(File, int), allocate(File, String, int, int)

allocate

public static FileBuffer allocate(File file,
                                  String mode,
                                  int initialCapacity,
                                  int maxCapacity)

Allocates a file buffer.

The resulting buffer will be initialized with a capacity of initialCapacity. The underlying FileBytes will be initialized to the nearest power of 2. As bytes are written to the file the buffer's capacity will double up to maxCapacity.

Parameters:

file - The file to allocate.

mode - The mode in which to open the underlying RandomAccessFile.

initialCapacity - The initial capacity of the buffer.

maxCapacity - The maximum allowed capacity of the buffer.

Returns:

The allocated buffer.

See Also:

allocate(File), allocate(File, int), allocate(File, int, int)

file

public File file()

Returns the underlying file object.

Returns:

The underlying file.

map

public MappedBuffer map(int size)

Maps a portion of the underlying file into memory in FileChannel.MapMode#READ_WRITE mode starting at the current position up to the given count.

Parameters:

size - The count of the bytes to map into memory.

Returns:

The mapped buffer.

Throws:

IllegalArgumentException - If count is greater than the maximum allowed MappedByteBuffer count: Integer.MAX_VALUE

map

public MappedBuffer map(int size,
                        FileChannel.MapMode mode)

Maps a portion of the underlying file into memory starting at the current position up to the given count.

Parameters:

size - The count of the bytes to map into memory.

mode - The mode in which to map the bytes into memory.

Returns:

The mapped buffer.

Throws:

IllegalArgumentException - If count is greater than the maximum allowed MappedByteBuffer count: Integer.MAX_VALUE

map

public MappedBuffer map(int offset,
                        int size)

Maps a portion of the underlying file into memory in FileChannel.MapMode#READ_WRITE mode starting at the given offset up to the given count.

Parameters:

offset - The offset from which to map bytes into memory.

size - The count of the bytes to map into memory.

Returns:

The mapped buffer.

Throws:

IllegalArgumentException - If count is greater than the maximum allowed MappedByteBuffer count: Integer.MAX_VALUE

map

public MappedBuffer map(int offset,
                        int size,
                        FileChannel.MapMode mode)

Maps a portion of the underlying file into memory starting at the given offset up to the given count.

Parameters:

offset - The offset from which to map bytes into memory.

size - The count of the bytes to map into memory.

mode - The mode in which to map the bytes into memory.

Returns:

The mapped buffer.

Throws:

IllegalArgumentException - If count is greater than the maximum allowed MappedByteBuffer count: Integer.MAX_VALUE

duplicate

public FileBuffer duplicate()

Description copied from interface: Buffer

Returns a duplicate of the buffer.

Returns:

A duplicate buffer.

duplicate

public FileBuffer duplicate(String mode)

Duplicates the buffer using the given mode.

Returns:

The mode with which to open the duplicate buffer.

delete

public void delete()

Deletes the underlying file.