io.atomix.storage.buffer

Class UnsafeMappedBytes

java.lang.Object

io.atomix.storage.buffer.AbstractBytes

io.atomix.storage.buffer.NativeBytes

io.atomix.storage.buffer.UnsafeMappedBytes

All Implemented Interfaces:

Bytes, BytesInput<Bytes>, BytesOutput<Bytes>, AutoCloseable

public class UnsafeMappedBytes
extends NativeBytes

Mapped bytes.

Mapped bytes provide direct access to memory from allocated by a MappedByteBuffer. Memory is allocated by opening and expanding the given File to the desired count and mapping the file contents into memory via FileChannel.map(FileChannel.MapMode, long, long).

Closing the bytes via Bytes.close() will result in BytesOutput.flush() being automatically called.

Author:

Jordan Halterman

Field Summary

Fields inherited from interface io.atomix.storage.buffer.Bytes

BOOLEAN, BYTE, CHARACTER, DOUBLE, FLOAT, INTEGER, LONG, MEDIUM, SHORT

Method Summary

Modifier and Type	Method and Description
static UnsafeMappedBytes	allocate(File file, FileChannel.MapMode mode, int size) Allocates a mapped buffer.
static UnsafeMappedBytes	allocate(File file, int size) Allocates a mapped buffer in FileChannel.MapMode#READ_WRITE mode.
void	close()
UnsafeMappedBytes	copy() Copies the bytes to a new byte array.
void	delete() Deletes the underlying file.
Bytes	flush() Flushes the bytes to the underlying persistence layer.
boolean	isDirect() Returns a boolean value indicating whether the bytes are direct.
boolean	isFile() Returns a boolean value indicating whether the bytes are backed by a file.

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

read, read, readByte, readChar, readDouble, readFloat, readInt, readLong, readMedium, readShort, readUnsignedMedium, resize, size, write, write, writeByte, writeChar, writeDouble, writeFloat, writeInt, writeLong, writeMedium, writeShort, writeUnsignedMedium, zero, zero, zero

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

order, order, readBoolean, readString, readString, readUnsignedByte, readUnsignedInt, readUnsignedShort, readUTF8, writeBoolean, writeString, writeString, writeUnsignedByte, writeUnsignedInt, writeUnsignedShort, writeUTF8

Methods inherited from class java.lang.Object

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

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

array, hasArray

Method Detail

allocate

public static UnsafeMappedBytes allocate(File file,
                                         int size)

Allocates a mapped buffer in FileChannel.MapMode#READ_WRITE mode.

Memory will be mapped by opening and expanding the given File to the desired count and mapping the file contents into memory via FileChannel.map(FileChannel.MapMode, long, long).

Parameters:

file - The file to map into memory. If the file doesn't exist it will be automatically created.

size - The count of the buffer to allocate (in bytes).

Returns:

The mapped buffer.

Throws:

NullPointerException - If file is null

IllegalArgumentException - If count is greater than MappedMemory.MAX_SIZE

See Also:

allocate(File, FileChannel.MapMode, int)

allocate

public static UnsafeMappedBytes allocate(File file,
                                         FileChannel.MapMode mode,
                                         int size)

Allocates a mapped buffer.

Memory will be mapped by opening and expanding the given File to the desired count and mapping the file contents into memory via FileChannel.map(FileChannel.MapMode, long, long).

Parameters:

file - The file to map into memory. If the file doesn't exist it will be automatically created.

mode - The mode with which to map the file.

size - The count of the buffer to allocate (in bytes).

Returns:

The mapped buffer.

Throws:

NullPointerException - If file is null

IllegalArgumentException - If count is greater than MappedMemory.MAX_SIZE

See Also:

allocate(File, int)

copy

public UnsafeMappedBytes copy()

Copies the bytes to a new byte array.

Returns:

A new UnsafeMappedBytes instance backed by a copy of this instance's memory.

isDirect

public boolean isDirect()

Description copied from interface: Bytes

Returns a boolean value indicating whether the bytes are direct.

Specified by:

isDirect in interface Bytes

Overrides:

isDirect in class NativeBytes

Returns:

Indicates whether the bytes are direct.

isFile

public boolean isFile()

Description copied from interface: Bytes

Returns a boolean value indicating whether the bytes are backed by a file.

Specified by:

isFile in interface Bytes

Overrides:

isFile in class AbstractBytes

Returns:

Indicates whether the bytes are backed by a file.

flush

public Bytes flush()

Description copied from interface: BytesOutput

Flushes the bytes to the underlying persistence layer.

Specified by:

flush in interface BytesOutput<Bytes>

Overrides:

flush in class AbstractBytes

Returns:

The flushed buffer.

close

public void close()

Specified by:

close in interface Bytes

Specified by:

close in interface AutoCloseable

Overrides:

close in class NativeBytes

delete

public void delete()

Deletes the underlying file.