OWriteCache (OrientDB 2.2.37 API)

All Known Implementing Classes:

ODirectMemoryOnlyDiskCache, OWOWCache
```
public interface OWriteCache
```

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`void`	`addBackgroundExceptionListener(OBackgroundExceptionListener listener)` Adds listener which is triggered if exception is cast inside background flush data thread.
`long`	`addFile(String fileName)`
`long`	`addFile(String fileName, long fileId)`
`void`	`addLowDiskSpaceListener(OLowDiskSpaceListener listener)`
`void`	`addPageIsBrokenListener(OPageIsBrokenListener listener)` Adds listener which is called by cache if corruption of file page is detected.
`long`	`bookFileId(String fileName)`
`boolean`	`checkLowDiskSpace()`
`OPageDataVerificationError[]`	`checkStoredPages(OCommandOutputListener commandOutputListener)`
`long[]`	`close()`
`void`	`close(long fileId, boolean flush)`
`long[]`	`delete()`
`void`	`deleteFile(long fileId)`
`boolean`	`exists(long fileId)`
`boolean`	`exists(String fileName)`
`long`	`externalFileId(int fileId)` Converts unique internal file id to external one.
`long`	`fileIdByName(String fileName)` Returns id associated with given file or value < 0 if such file does not exist.
`boolean`	`fileIdsAreEqual(long firsId, long secondId)`
`String`	`fileNameById(long fileId)`
`Map<String,Long>`	`files()`
`void`	`flush()`
`void`	`flush(long fileId)`
`long`	`getExclusiveWriteCachePagesSize()`
`long`	`getFilledUpTo(long fileId)`
`int`	`getId()`
`OPerformanceStatisticManager`	`getPerformanceStatisticManager()`
`File`	`getRootDirectory()` Directory which contains all files managed by write cache.
`int`	`internalFileId(long fileId)` Returns internal file id which is unique and always the same for given file in contrary to external id which changes over close/open cycle of cache.
`OCachePointer[]`	`load(long fileId, long startPageIndex, int pageCount, boolean addNewPages, OModifiableBoolean cacheHit, boolean verifyChecksums)`
`long`	`loadFile(String fileName)` Registers new file in write cache and returns file id assigned to this file.
`void`	`makeFuzzyCheckpoint()`
`int`	`pageSize()`
`void`	`removeBackgroundExceptionListener(OBackgroundExceptionListener listener)` Removes listener which is triggered if exception is cast inside background flush data thread.
`void`	`removeLowDiskSpaceListener(OLowDiskSpaceListener listener)`
`void`	`removePageIsBrokenListener(OPageIsBrokenListener listener)` Removes listener which is called by cache if corruption of file page is detected.
`void`	`renameFile(long fileId, String oldFileName, String newFileName)`
`String`	`restoreFileById(long fileId)` Finds if there was file in write cache with given id which is deleted right now.
`void`	`startFuzzyCheckpoints()`
`Future`	`store(long fileId, long pageIndex, OCachePointer dataPointer)`
`void`	`truncateFile(long fileId)`
`boolean`	`verifyPage(long fileId, long pageIndex)`

- Method Detail
  - startFuzzyCheckpoints
```
void startFuzzyCheckpoints()
```
  - addPageIsBrokenListener
```
void addPageIsBrokenListener(OPageIsBrokenListener listener)
```
    Adds listener which is called by cache if corruption of file page is detected.
  - removePageIsBrokenListener
```
void removePageIsBrokenListener(OPageIsBrokenListener listener)
```
    Removes listener which is called by cache if corruption of file page is detected.
  - addLowDiskSpaceListener
```
void addLowDiskSpaceListener(OLowDiskSpaceListener listener)
```
  - removeLowDiskSpaceListener
```
void removeLowDiskSpaceListener(OLowDiskSpaceListener listener)
```
  - bookFileId
```
long bookFileId(String fileName)
         throws IOException
```
    Throws:
    
    IOException
  - loadFile
```
long loadFile(String fileName)
       throws IOException
```
    Registers new file in write cache and returns file id assigned to this file. File id consist of two parts:
    1. Internal id is permanent and can not be changed during life of storage internalFileId(long)
    2. Write cache id which is changed between storage open/close cycles
    If file with the same name is deleted and then new file is created this file with have the same internal id.
    Parameters:
    
    fileName - Name of file to register inside storage.
    
    Returns:
    
    Id of registered file
    
    Throws:
    
    IOException
  - addFile
```
long addFile(String fileName)
      throws IOException
```
    Throws:
    
    IOException
  - addFile
```
long addFile(String fileName,
             long fileId)
      throws IOException
```
    Throws:
    
    IOException
  - fileIdByName
```
long fileIdByName(String fileName)
```
    Returns id associated with given file or value < 0 if such file does not exist.
    
    Parameters:
    
    fileName - File name id of which has to be returned.
    
    Returns:
    
    id associated with given file or value < 0 if such file does not exist.
  - checkLowDiskSpace
```
boolean checkLowDiskSpace()
```
  - makeFuzzyCheckpoint
```
void makeFuzzyCheckpoint()
```
  - exists
```
boolean exists(String fileName)
```
  - exists
```
boolean exists(long fileId)
```
  - store
```
Future store(long fileId,
             long pageIndex,
             OCachePointer dataPointer)
```
  - load
```
OCachePointer[] load(long fileId,
                     long startPageIndex,
                     int pageCount,
                     boolean addNewPages,
                     OModifiableBoolean cacheHit,
                     boolean verifyChecksums)
              throws IOException
```
    Throws:
    
    IOException
  - flush
```
void flush(long fileId)
```
  - flush
```
void flush()
```
  - getFilledUpTo
```
long getFilledUpTo(long fileId)
            throws IOException
```
    Throws:
    
    IOException
  - getExclusiveWriteCachePagesSize
```
long getExclusiveWriteCachePagesSize()
```
  - deleteFile
```
void deleteFile(long fileId)
         throws IOException
```
    Throws:
    
    IOException
  - truncateFile
```
void truncateFile(long fileId)
           throws IOException
```
    Throws:
    
    IOException
  - renameFile
```
void renameFile(long fileId,
                String oldFileName,
                String newFileName)
         throws IOException
```
    Throws:
    
    IOException
  - close
```
long[] close()
      throws IOException
```
    Throws:
    
    IOException
  - close
```
void close(long fileId,
           boolean flush)
    throws IOException
```
    Throws:
    
    IOException
  - checkStoredPages
```
OPageDataVerificationError[] checkStoredPages(OCommandOutputListener commandOutputListener)
```
  - delete
```
long[] delete()
       throws IOException
```
    Throws:
    
    IOException
  - fileNameById
```
String fileNameById(long fileId)
```
  - getId
```
int getId()
```
  - files
```
Map<String,Long> files()
```
  - pageSize
```
int pageSize()
```
  - restoreFileById
```
String restoreFileById(long fileId)
                throws IOException
```
    Finds if there was file in write cache with given id which is deleted right now. If such file exists it creates new file with the same name at it was in deleted file.
    
    Parameters:
    
    fileId - If of file which should be restored
    
    Returns:
    
    Name of restored file or null if such name does not exist
    
    Throws:
    
    IOException
  - fileIdsAreEqual
```
boolean fileIdsAreEqual(long firsId,
                        long secondId)
```
  - addBackgroundExceptionListener
```
void addBackgroundExceptionListener(OBackgroundExceptionListener listener)
```
    Adds listener which is triggered if exception is cast inside background flush data thread.
    
    Parameters:
    
    listener - Listener to trigger
  - removeBackgroundExceptionListener
```
void removeBackgroundExceptionListener(OBackgroundExceptionListener listener)
```
    Removes listener which is triggered if exception is cast inside background flush data thread.
    
    Parameters:
    
    listener - Listener to remove
  - getRootDirectory
```
File getRootDirectory()
```
    Directory which contains all files managed by write cache.
    
    Returns:
    
    Directory which contains all files managed by write cache or null in case of in memory database.
  - internalFileId
```
int internalFileId(long fileId)
```
    Returns internal file id which is unique and always the same for given file in contrary to external id which changes over close/open cycle of cache.
    
    Parameters:
    
    fileId - External file id.
    
    Returns:
    
    Internal file id.
  - externalFileId
```
long externalFileId(int fileId)
```
    Converts unique internal file id to external one. External id is combination of internal id and write cache id, which changes every time when cache is closed and opened again.
    
    Parameters:
    
    fileId - Internal file id.
    
    Returns:
    
    External file id.
    
    See Also:
    
    internalFileId(long), getId()
  - getPerformanceStatisticManager
```
OPerformanceStatisticManager getPerformanceStatisticManager()
```
  - verifyPage
```
boolean verifyPage(long fileId,
                   long pageIndex)
            throws IOException
```
    Throws:
    
    IOException

Interface OWriteCache

Method Summary

Method Detail

startFuzzyCheckpoints

addPageIsBrokenListener

removePageIsBrokenListener

addLowDiskSpaceListener

removeLowDiskSpaceListener

bookFileId

loadFile

addFile

addFile

fileIdByName

checkLowDiskSpace

makeFuzzyCheckpoint

exists

exists

store

load

flush

flush

getFilledUpTo

getExclusiveWriteCachePagesSize

deleteFile

truncateFile

renameFile

close

close

checkStoredPages

delete

fileNameById

getId

files

pageSize

restoreFileById

fileIdsAreEqual

addBackgroundExceptionListener

removeBackgroundExceptionListener

getRootDirectory

internalFileId

externalFileId

getPerformanceStatisticManager

verifyPage