Package org.apache.druid.storage

Class NilStorageConnector

java.lang.Object

org.apache.druid.storage.NilStorageConnector

All Implemented Interfaces:

StorageConnector

public class NilStorageConnector
extends Object
implements StorageConnector

Method Summary

Modifier and Type	Method	Description
void	deleteFile(String path)	Delete file present at the input path.
void	deleteFiles(Iterable<String> paths)	Delete files present at the input paths.
void	deleteRecursively(String path)	Delete a directory pointed to by the path and also recursively deletes all files/directories in said directory.
static NilStorageConnector	getInstance()
Iterator<String>	listDir(String dirName)	Returns a lazy iterator containing all the files present in the path.
boolean	pathExists(String path)	Check if the path exists in the underlying storage layer.
InputStream	read(String path)	Reads the data present at the path in the underlying storage system.
InputStream	readRange(String path, long from, long size)	Reads the data present for a given range at the path in the underlying storage system.
OutputStream	write(String path)	Open an OutputStream for writing data to the path in the underlying storage system.

Methods inherited from class java.lang.Object

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

Method Details

getInstance

public static NilStorageConnector getInstance()

pathExists

public boolean pathExists(String path)

Description copied from interface: StorageConnector

Check if the path exists in the underlying storage layer. Most implementations prepend the input path with a basePath.

Specified by:

pathExists in interface StorageConnector

Returns:

true if path exists else false.

read

public InputStream read(String path)

Description copied from interface: StorageConnector

Reads the data present at the path in the underlying storage system. Most implementations prepend the input path with a basePath. The caller should take care of closing the stream when done or in case of error.

Specified by:

read in interface StorageConnector

Returns:

InputStream

readRange

public InputStream readRange(String path,
 long from,
 long size)

Description copied from interface: StorageConnector

Reads the data present for a given range at the path in the underlying storage system. Most implementations prepend the input path with a basePath. The caller should take care of closing the stream when done or in case of error. Further, the caller must ensure that the start offset and the size of the read are valid parameters for the given path for correct behavior.

Specified by:

readRange in interface StorageConnector

Parameters:

path - The path to read data from

from - Start offset of the read in the path

size - Length of the read to be done

Returns:

InputStream starting from the given offset limited by the given size

write

public OutputStream write(String path)

Description copied from interface: StorageConnector

Open an OutputStream for writing data to the path in the underlying storage system. Most implementations prepend the input path with a basePath. If an object exists at the path, the existing object will be overwritten by the write operation. Callers are adivised to namespace there files as there might be race conditions. The caller should take care of closing the stream when done or in case of error.

Specified by:

write in interface StorageConnector

Parameters:

path - to write

Returns:

OutputStream to the path

deleteFile

public void deleteFile(String path)

Description copied from interface: StorageConnector

Delete file present at the input path. Most implementations prepend the input path with a basePath. If the path is a directory, this method throws an exception.

Specified by:

deleteFile in interface StorageConnector

Parameters:

path - to delete

deleteFiles

public void deleteFiles(Iterable<String> paths)

Description copied from interface: StorageConnector

Delete files present at the input paths. Most implementations prepend all the input paths with the basePath.
This method is recommended in case we need to delete a batch of files. If the path is a directory, this method throws an exception.

Specified by:

deleteFiles in interface StorageConnector

Parameters:

paths - Iterable of the paths to delete.

deleteRecursively

public void deleteRecursively(String path)

Description copied from interface: StorageConnector

Delete a directory pointed to by the path and also recursively deletes all files/directories in said directory. Most implementations prepend the input path with a basePath.

Specified by:

deleteRecursively in interface StorageConnector

Parameters:

path - path

listDir

public Iterator<String> listDir(String dirName)

Description copied from interface: StorageConnector

Returns a lazy iterator containing all the files present in the path. The returned filenames should be such that joining the dirName and the file name form the full path that can be used as the arguments for other methods of the storage connector. For example, for a S3 path such as s3://bucket/parent1/parent2/child, the filename returned for the input path "parent1/parent2" should be "child" and for input "parent1" should be "parent2/child"

Specified by:

listDir in interface StorageConnector