org.apache.iotdb.db.query.control

类 FileReaderManager

java.lang.Object

org.apache.iotdb.db.query.control.FileReaderManager

public class FileReaderManager
extends Object

FileReaderManager is a singleton, which is used to manage all file readers(opened file streams) to ensure that each file is opened at most once.

方法概要

限定符和类型	方法和说明
void	closeAndRemoveAllOpenedReaders() Only for EnvironmentUtils.cleanEnv method.
void	closeFileAndRemoveReader(String filePath)
boolean	contains(TsFileResource tsFile, boolean isClosed) This method is only for unit tests.
void	decreaseFileReaderReference(TsFileResource tsFile, boolean isClosed) Decrease the reference count of the reader specified by filePath.
TsFileSequenceReader	get(String filePath, boolean isClosed) Get the reader of the file(tsfile or unseq tsfile) indicated by filePath.
static FileReaderManager	getInstance()
void	increaseFileReaderReference(TsFileResource tsFile, boolean isClosed) Increase the reference count of the reader specified by filePath.
void	writeFileReferenceInfo()

从类继承的方法 java.lang.Object

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

方法详细资料

getInstance

public static FileReaderManager getInstance()

closeFileAndRemoveReader

public void closeFileAndRemoveReader(String filePath)
                              throws IOException

抛出:

IOException

get

public TsFileSequenceReader get(String filePath,
                                boolean isClosed)
                         throws IOException

Get the reader of the file(tsfile or unseq tsfile) indicated by filePath. If the reader already exists, just get it from closedFileReaderMap or unclosedFileReaderMap depending on isClosing . Otherwise a new reader will be created and cached.

参数:

filePath - the path of the file, of which the reader is desired.

isClosed - whether the corresponding file still receives insertions or not.

返回:

the reader of the file specified by filePath.

抛出:

IOException - when reader cannot be created.

increaseFileReaderReference

public void increaseFileReaderReference(TsFileResource tsFile,
                                        boolean isClosed)

Increase the reference count of the reader specified by filePath. Only when the reference count of a reader equals zero, the reader can be closed and removed.

decreaseFileReaderReference

public void decreaseFileReaderReference(TsFileResource tsFile,
                                        boolean isClosed)

Decrease the reference count of the reader specified by filePath. This method is latch-free. Only when the reference count of a reader equals zero, the reader can be closed and removed.

closeAndRemoveAllOpenedReaders

public void closeAndRemoveAllOpenedReaders()
                                    throws IOException

Only for EnvironmentUtils.cleanEnv method. To make sure that unit tests and integration tests will not conflict with each other.

抛出:

IOException

contains

public boolean contains(TsFileResource tsFile,
                        boolean isClosed)

This method is only for unit tests.

writeFileReferenceInfo

public void writeFileReferenceInfo()