MmapFile (openmessaging-dledger 0.2.2 API)

所有已知实现类:

DefaultMmapFile
```
public interface MmapFile
```

方法概要

所有方法实例方法抽象方法
限定符和类型	方法和说明
`boolean`	`appendMessage(byte[] data)` Appends a raw message data represents by a byte array to the current `MappedFile`.
`boolean`	`appendMessage(byte[] data, int offset, int length)` Appends a raw message data represents by a byte array to the current `MappedFile`, starting at the given offset in the array.
`int`	`commit(int commitLeastPages)` Flushes the data in the secondary cache to page cache or disk immediately.
`boolean`	`destroy(long intervalForcibly)` Destroys the file and delete it from the file system.
`int`	`flush(int flushLeastPages)` Flushes the data in cache to disk immediately.
`boolean`	`getData(int pos, int size, java.nio.ByteBuffer byteBuffer)` get the data from file channel
`java.nio.channels.FileChannel`	`getFileChannel()` Returns the `FileChannel` behind the `MappedFile`.
`long`	`getFileFromOffset()` Returns the global offset of the current {code MappedFile}, it's a long value of the file name.
`java.lang.String`	`getFileName()` Returns the file name of the `MappedFile`.
`int`	`getFileSize()` Returns the file size of the `MappedFile`.
`int`	`getFlushedPosition()` Returns the flushed position of this mapped file.
`long`	`getLastModifiedTimestamp()` Returns the last modified timestamp of the file.
`java.nio.MappedByteBuffer`	`getMappedByteBuffer()` Returns the mapped byte buffer behind the mapped file.
`int`	`getReadPosition()` Returns the current max readable position of this mapped file.
`int`	`getStartPosition()` Returns the start position of this mapped file, before which the data is truncated
`int`	`getWrotePosition()` Returns the wrote position of this mapped file.
`boolean`	`hold()` Increases the reference count by `1`.
`boolean`	`isAvailable()` Returns true if this `MappedFile` is available.
`boolean`	`isFirstCreateInQueue()` Returns true if the current file is first mapped file of some consume queue.
`boolean`	`isFull()` Returns true if this `MappedFile` is full and no new messages can be added.
`void`	`release()` Decreases the reference count by `1` and clean up the mapped file if the reference count reaches at `0`.
`SelectMmapBufferResult`	`selectMappedBuffer(int pos)` Selects a slice of the mapped byte buffer's sub-region behind the mapped file, starting at the given position.
`SelectMmapBufferResult`	`selectMappedBuffer(int pos, int size)` Selects a slice of the mapped byte buffer's sub-region behind the mapped file, starting at the given position.
`void`	`setCommittedPosition(int committedPosition)` Sets the committed position of this mapped file.
`void`	`setFirstCreateInQueue(boolean firstCreateInQueue)` Sets the flag whether the current file is first mapped file of some consume queue.
`void`	`setFlushedPosition(int flushedPosition)` Sets the flushed position of this mapped file.
`void`	`setStartPosition(int startPosition)` Sets the start position of this mapped file.
`void`	`setWrotePosition(int wrotePosition)` Sets the wrote position of this mapped file.
`void`	`shutdown(long intervalForcibly)` Shutdowns the file and mark it unavailable.
`java.nio.ByteBuffer`	`sliceByteBuffer()` Returns a slice of the mapped byte buffer behind the mapped file.

- 方法详细资料
  - getFileName
```
java.lang.String getFileName()
```
    Returns the file name of the MappedFile.
    
    返回:
    
    the file name
  - getFileSize
```
int getFileSize()
```
    Returns the file size of the MappedFile.
    
    返回:
    
    the file size
  - getFileChannel
```
java.nio.channels.FileChannel getFileChannel()
```
    Returns the FileChannel behind the MappedFile.
    
    返回:
    
    the file channel
  - isFull
```
boolean isFull()
```
    Returns true if this MappedFile is full and no new messages can be added.
    
    返回:
    
    true if the file is full
  - isAvailable
```
boolean isAvailable()
```
    Returns true if this MappedFile is available.
    The mapped file will be not available if it's shutdown or destroyed.
    
    返回:
    
    true if the file is available
  - appendMessage
```
boolean appendMessage(byte[] data)
```
    Appends a raw message data represents by a byte array to the current MappedFile.
    
    参数:
    
    data - the byte array to append
    
    返回:
    
    true if success; false otherwise.
  - appendMessage
```
boolean appendMessage(byte[] data,
                      int offset,
                      int length)
```
    Appends a raw message data represents by a byte array to the current MappedFile, starting at the given offset in the array.
    
    参数:
    
    data - the byte array to append
    
    offset - the offset within the array of the first byte to be read
    
    length - the number of bytes to be read from the given array
    
    返回:
    
    true if success; false otherwise.
  - getFileFromOffset
```
long getFileFromOffset()
```
    Returns the global offset of the current {code MappedFile}, it's a long value of the file name.
    
    返回:
    
    the offset of this file
  - flush
```
int flush(int flushLeastPages)
```
    Flushes the data in cache to disk immediately.
    
    参数:
    
    flushLeastPages - the least pages to flush
    
    返回:
    
    the flushed position after the method call
  - commit
```
int commit(int commitLeastPages)
```
    Flushes the data in the secondary cache to page cache or disk immediately.
    
    参数:
    
    commitLeastPages - the least pages to commit
    
    返回:
    
    the committed position after the method call
  - selectMappedBuffer
```
SelectMmapBufferResult selectMappedBuffer(int pos,
                                          int size)
```
    Selects a slice of the mapped byte buffer's sub-region behind the mapped file, starting at the given position.
    
    参数:
    
    pos - the given position
    
    size - the size of the returned sub-region
    
    返回:
    
    a SelectMappedBufferResult instance contains the selected slice
  - selectMappedBuffer
```
SelectMmapBufferResult selectMappedBuffer(int pos)
```
    Selects a slice of the mapped byte buffer's sub-region behind the mapped file, starting at the given position.
    
    参数:
    
    pos - the given position
    
    返回:
    
    a SelectMappedBufferResult instance contains the selected slice
  - getMappedByteBuffer
```
java.nio.MappedByteBuffer getMappedByteBuffer()
```
    Returns the mapped byte buffer behind the mapped file.
    
    返回:
    
    the mapped byte buffer
  - sliceByteBuffer
```
java.nio.ByteBuffer sliceByteBuffer()
```
    Returns a slice of the mapped byte buffer behind the mapped file.
    
    返回:
    
    the slice of the mapped byte buffer
  - getLastModifiedTimestamp
```
long getLastModifiedTimestamp()
```
    Returns the last modified timestamp of the file.
    
    返回:
    
    the last modified timestamp
  - destroy
```
boolean destroy(long intervalForcibly)
```
    Destroys the file and delete it from the file system.
    
    参数:
    
    intervalForcibly - If true then this method will destroy the file forcibly and ignore the reference
    
    返回:
    
    true if success; false otherwise.
  - shutdown
```
void shutdown(long intervalForcibly)
```
    Shutdowns the file and mark it unavailable.
    
    参数:
    
    intervalForcibly - If true then this method will shutdown the file forcibly and ignore the reference
  - release
```
void release()
```
    Decreases the reference count by 1 and clean up the mapped file if the reference count reaches at 0.
  - hold
```
boolean hold()
```
    Increases the reference count by 1.
    
    返回:
    
    true if success; false otherwise.
  - isFirstCreateInQueue
```
boolean isFirstCreateInQueue()
```
    Returns true if the current file is first mapped file of some consume queue.
    
    返回:
    
    true or false
  - setFirstCreateInQueue
```
void setFirstCreateInQueue(boolean firstCreateInQueue)
```
    Sets the flag whether the current file is first mapped file of some consume queue.
    
    参数:
    
    firstCreateInQueue - true or false
  - getFlushedPosition
```
int getFlushedPosition()
```
    Returns the flushed position of this mapped file.
    
    返回:
    
    the flushed posotion
  - setFlushedPosition
```
void setFlushedPosition(int flushedPosition)
```
    Sets the flushed position of this mapped file.
    
    参数:
    
    flushedPosition - the specific flushed position
  - getStartPosition
```
int getStartPosition()
```
    Returns the start position of this mapped file, before which the data is truncated
    
    返回:
    
    the wrote position
  - setStartPosition
```
void setStartPosition(int startPosition)
```
    Sets the start position of this mapped file.
    
    参数:
    
    startPosition - the specific start position
  - getWrotePosition
```
int getWrotePosition()
```
    Returns the wrote position of this mapped file.
    
    返回:
    
    the wrote position
  - setWrotePosition
```
void setWrotePosition(int wrotePosition)
```
    Sets the wrote position of this mapped file.
    
    参数:
    
    wrotePosition - the specific wrote position
  - getReadPosition
```
int getReadPosition()
```
    Returns the current max readable position of this mapped file.
    
    返回:
    
    the max readable position
  - setCommittedPosition
```
void setCommittedPosition(int committedPosition)
```
    Sets the committed position of this mapped file.
    
    参数:
    
    committedPosition - the specific committed position
  - getData
```
boolean getData(int pos,
                int size,
                java.nio.ByteBuffer byteBuffer)
```
    get the data from file channel
    
    参数:
    
    pos -
    
    size -
    
    byteBuffer -
    
    返回:

接口 MmapFile

方法概要

方法详细资料

getFileName

getFileSize

getFileChannel

isFull

isAvailable

appendMessage

appendMessage

getFileFromOffset

flush

commit

selectMappedBuffer

selectMappedBuffer

getMappedByteBuffer

sliceByteBuffer

getLastModifiedTimestamp

destroy

shutdown

release

hold

isFirstCreateInQueue

setFirstCreateInQueue

getFlushedPosition

setFlushedPosition

getStartPosition

setStartPosition

getWrotePosition

setWrotePosition

getReadPosition

setCommittedPosition

getData