org.apache.commons.vfs2.provider.hdfs

Class HdfsFileObject

java.lang.Object

org.apache.commons.vfs2.provider.AbstractFileObject<HdfsFileSystem>

org.apache.commons.vfs2.provider.hdfs.HdfsFileObject

All Implemented Interfaces:

Closeable, AutoCloseable, Comparable<FileObject>, Iterable<FileObject>, FileObject

public class HdfsFileObject
extends AbstractFileObject<HdfsFileSystem>

A VFS representation of an HDFS file.

Since:

2.1

Field Summary

Fields inherited from class org.apache.commons.vfs2.provider.AbstractFileObject

DEFAULT_BUFFER_SIZE

Fields inherited from interface org.apache.commons.vfs2.FileObject

EMPTY_ARRAY

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	HdfsFileObject(AbstractFileName name, HdfsFileSystem fs, org.apache.hadoop.fs.FileSystem hdfs, org.apache.hadoop.fs.Path p) Constructs a new HDFS FileObject

Method Summary

Modifier and Type	Method and Description
boolean	canRenameTo(FileObject newfile) Queries the object if a simple rename to the file name of newfile is possible.
protected void	doAttach() Attaches this file object to its file resource.
protected void	doCreateFolder() Creates this file as a folder.
protected void	doDelete() Deletes the file.
protected Map<String,Object>	doGetAttributes() Returns the attributes of this file.
protected long	doGetContentSize() Returns the size of the file content (in bytes).
protected InputStream	doGetInputStream(int bufferSize) Creates an input stream to read the file content from.
protected long	doGetLastModifiedTime() Returns the last modified time of this file.
protected OutputStream	doGetOutputStream(boolean append) Creates an output stream to write the file content to.
protected RandomAccessContent	doGetRandomAccessContent(RandomAccessMode mode) Creates access to the file for random i/o.
protected FileType	doGetType() Determines the type of this file.
protected boolean	doIsHidden() Determines if this file is hidden.
protected boolean	doIsReadable() Determines if this file can be read.
protected boolean	doIsWriteable() Determines if this file can be written to.
protected String[]	doListChildren() Lists the children of this file.
protected FileObject[]	doListChildrenResolved() Lists the children of this file.
protected void	doRemoveAttribute(String attrName) Removes an attribute of this file.
protected void	doRename(FileObject newfile) Renames the file.
protected void	doSetAttribute(String attrName, Object value) Sets an attribute of this file.
protected boolean	doSetLastModifiedTime(long modtime) Sets the last modified time of this file.
boolean	exists() Determines if the file exists.

Methods inherited from class org.apache.commons.vfs2.provider.AbstractFileObject

childrenChanged, close, compareTo, copyFrom, createFile, createFolder, delete, delete, deleteAll, doCreateFileContent, doDetach, doGetCertificates, doGetInputStream, doIsExecutable, doIsSameFile, doIsSymbolicLink, doSetExecutable, doSetReadable, doSetWritable, endOutput, finalize, findFiles, findFiles, getAbstractFileSystem, getChild, getChildren, getContent, getFileContentInfoFactory, getFileOperations, getFileSystem, getInputStream, getInputStream, getName, getOutputStream, getOutputStream, getParent, getPublicURIString, getRandomAccessContent, getType, getURL, handleChanged, handleCreate, handleDelete, holdObject, injectType, isAttached, isContentOpen, isExecutable, isFile, isFolder, isHidden, isReadable, isSameFile, isSymbolicLink, isWriteable, iterator, listFiles, moveTo, notifyAllStreamsClosed, onChange, onChildrenChanged, refresh, resolveFile, resolveFile, setExecutable, setReadable, setWritable, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.commons.vfs2.FileObject

getPath, getURI

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

HdfsFileObject

protected HdfsFileObject(AbstractFileName name,
                         HdfsFileSystem fs,
                         org.apache.hadoop.fs.FileSystem hdfs,
                         org.apache.hadoop.fs.Path p)

Constructs a new HDFS FileObject

Parameters:

name - FileName

fs - HdfsFileSystem instance

hdfs - Hadoop FileSystem instance

p - Path to the file in HDFS

Method Detail

canRenameTo

public boolean canRenameTo(FileObject newfile)

Description copied from class: AbstractFileObject

Queries the object if a simple rename to the file name of newfile is possible.

Specified by:

canRenameTo in interface FileObject

Overrides:

canRenameTo in class AbstractFileObject<HdfsFileSystem>

Parameters:

newfile - the new file name

Returns:

true if rename is possible

See Also:

AbstractFileObject.canRenameTo(org.apache.commons.vfs2.FileObject)

doAttach

protected void doAttach()
                 throws Exception

Description copied from class: AbstractFileObject

Attaches this file object to its file resource.

This method is called before any of the doBlah() or onBlah() methods. Sub-classes can use this method to perform lazy initialization.

This implementation does nothing.

Overrides:

doAttach in class AbstractFileObject<HdfsFileSystem>

Throws:

Exception - if an error occurs.

See Also:

AbstractFileObject.doAttach()

doCreateFolder

protected void doCreateFolder()
                       throws Exception

Description copied from class: AbstractFileObject

Creates this file as a folder. Is only called when:

• AbstractFileObject.doGetType() returns FileType.IMAGINARY.
• The parent folder exists and is writable, or this file is the root of the file system.

This implementation throws an exception.

Overrides:

doCreateFolder in class AbstractFileObject<HdfsFileSystem>

Throws:

Exception - if an error occurs.

Since:

2.7.0

See Also:

AbstractFileObject.doCreateFolder()

doDelete

protected void doDelete()
                 throws Exception

Description copied from class: AbstractFileObject

Deletes the file. Is only called when:

• AbstractFileObject.doGetType() does not return FileType.IMAGINARY.
• AbstractFileObject.doIsWriteable() returns true.
• This file has no children, if a folder.

This implementation throws an exception.

Overrides:

doDelete in class AbstractFileObject<HdfsFileSystem>

Throws:

Exception - if an error occurs.

Since:

2.7.0

See Also:

AbstractFileObject.doDelete()

doGetAttributes

protected Map<String,Object> doGetAttributes()
                                      throws Exception

Description copied from class: AbstractFileObject

Returns the attributes of this file. Is only called if AbstractFileObject.doGetType() does not return FileType.IMAGINARY.

This implementation always returns an empty map.

Overrides:

doGetAttributes in class AbstractFileObject<HdfsFileSystem>

Returns:

The attributes of the file.

Throws:

Exception - if an error occurs.

See Also:

AbstractFileObject.doGetAttributes()

doGetContentSize

protected long doGetContentSize()
                         throws Exception

Description copied from class: AbstractFileObject

Returns the size of the file content (in bytes). Is only called if AbstractFileObject.doGetType() returns FileType.FILE.

Specified by:

doGetContentSize in class AbstractFileObject<HdfsFileSystem>

Returns:

The size of the file in bytes.

Throws:

Exception - if an error occurs.

See Also:

AbstractFileObject.doGetContentSize()

doGetInputStream

protected InputStream doGetInputStream(int bufferSize)
                                throws Exception

Description copied from class: AbstractFileObject

Creates an input stream to read the file content from. Is only called if AbstractFileObject.doGetType() returns FileType.FILE.

It is guaranteed that there are no open output streams for this file when this method is called.

The returned stream does not have to be buffered.

Overrides:

doGetInputStream in class AbstractFileObject<HdfsFileSystem>

Parameters:

bufferSize - Buffer size hint.

Returns:

An InputStream to read the file content.

Throws:

Exception - if an error occurs.

See Also:

AbstractFileObject.doGetInputStream(int)

doGetLastModifiedTime

protected long doGetLastModifiedTime()
                              throws Exception

Description copied from class: AbstractFileObject

Returns the last modified time of this file. Is only called if AbstractFileObject.doGetType() does not return

This implementation throws an exception.

Overrides:

doGetLastModifiedTime in class AbstractFileObject<HdfsFileSystem>

Returns:

The last modification time.

Throws:

Exception - if an error occurs.

See Also:

AbstractFileObject.doGetLastModifiedTime()

doGetOutputStream

protected OutputStream doGetOutputStream(boolean append)
                                  throws Exception

Description copied from class: AbstractFileObject

Creates an output stream to write the file content to. Is only called if:

• AbstractFileObject.doIsWriteable() returns true.
• AbstractFileObject.doGetType() returns FileType.FILE, or AbstractFileObject.doGetType() returns FileType.IMAGINARY, and the file's parent exists and is a folder.

It is guaranteed that there are no open stream (input or output) for this file when this method is called.

The returned stream does not have to be buffered.

This implementation throws an exception.

Overrides:

doGetOutputStream in class AbstractFileObject<HdfsFileSystem>

Parameters:

append - true if the file should be appended to, false if it should be overwritten.

Returns:

An OutputStream to write to the file.

Throws:

Exception - if an error occurs.

Since:

2.7.0

See Also:

AbstractFileObject.doGetOutputStream(boolean)

doGetRandomAccessContent

protected RandomAccessContent doGetRandomAccessContent(RandomAccessMode mode)
                                                throws Exception

Description copied from class: AbstractFileObject

Creates access to the file for random i/o. Is only called if AbstractFileObject.doGetType() returns FileType.FILE.

It is guaranteed that there are no open output streams for this file when this method is called.

Overrides:

doGetRandomAccessContent in class AbstractFileObject<HdfsFileSystem>

Parameters:

mode - The mode to access the file.

Returns:

The RandomAccessContext.

Throws:

Exception - if an error occurs.

See Also:

(org.apache.commons.vfs2.util.RandomAccessMode)

doGetType

protected FileType doGetType()
                      throws Exception

Description copied from class: AbstractFileObject

Determines the type of this file. Must not return null. The return value of this method is cached, so the implementation can be expensive.

Specified by:

doGetType in class AbstractFileObject<HdfsFileSystem>

Returns:

the type of the file.

Throws:

Exception - if an error occurs.

See Also:

AbstractFileObject.doGetType()

doIsHidden

protected boolean doIsHidden()
                      throws Exception

Description copied from class: AbstractFileObject

Determines if this file is hidden. Is only called if AbstractFileObject.doGetType() does not return FileType.IMAGINARY.

This implementation always returns false.

Overrides:

doIsHidden in class AbstractFileObject<HdfsFileSystem>

Returns:

true if the file is hidden, false otherwise.

Throws:

Exception - if an error occurs.

See Also:

AbstractFileObject.doIsHidden()

doIsReadable

protected boolean doIsReadable()
                        throws Exception

Description copied from class: AbstractFileObject

Determines if this file can be read. Is only called if AbstractFileObject.doGetType() does not return FileType.IMAGINARY.

This implementation always returns true.

Overrides:

doIsReadable in class AbstractFileObject<HdfsFileSystem>

Returns:

true if the file is readable, false otherwise.

Throws:

Exception - if an error occurs.

See Also:

AbstractFileObject.doIsReadable()

doIsWriteable

protected boolean doIsWriteable()
                         throws Exception

Description copied from class: AbstractFileObject

Determines if this file can be written to. Is only called if AbstractFileObject.doGetType() does not return FileType.IMAGINARY.

This implementation always returns true.

Overrides:

doIsWriteable in class AbstractFileObject<HdfsFileSystem>

Returns:

true if the file is writable.

Throws:

Exception - if an error occurs.

See Also:

AbstractFileObject.doIsWriteable()

doListChildren

protected String[] doListChildren()
                           throws Exception

Description copied from class: AbstractFileObject

Lists the children of this file. Is only called if AbstractFileObject.doGetType() returns FileType.FOLDER. The return value of this method is cached, so the implementation can be expensive.

Specified by:

doListChildren in class AbstractFileObject<HdfsFileSystem>

Returns:

a possible empty String array if the file is a directory or null or an exception if the file is not a directory or can't be read.

Throws:

Exception - if an error occurs.

See Also:

AbstractFileObject.doListChildren()

doListChildrenResolved

protected FileObject[] doListChildrenResolved()
                                       throws Exception

Description copied from class: AbstractFileObject

Lists the children of this file.

Is only called if AbstractFileObject.doGetType() returns FileType.FOLDER.

The return value of this method is cached, so the implementation can be expensive. Other than doListChildren you could return FileObject's to e.g. reinitialize the type of the file.

(Introduced for Webdav: "permission denied on resource" during getType())

Overrides:

doListChildrenResolved in class AbstractFileObject<HdfsFileSystem>

Returns:

The children of this FileObject.

Throws:

Exception - if an error occurs.

See Also:

AbstractFileObject.doListChildrenResolved()

doRemoveAttribute

protected void doRemoveAttribute(String attrName)
                          throws Exception

Description copied from class: AbstractFileObject

Removes an attribute of this file.

Is only called if AbstractFileObject.doGetType() does not return FileType.IMAGINARY.

This implementation throws an exception.

Overrides:

doRemoveAttribute in class AbstractFileObject<HdfsFileSystem>

Parameters:

attrName - The name of the attribute to remove.

Throws:

Exception - if an error occurs.

See Also:

AbstractFileObject.doRemoveAttribute(java.lang.String)

doRename

protected void doRename(FileObject newfile)
                 throws Exception

Description copied from class: AbstractFileObject

Renames the file.

Is only called when:

• AbstractFileObject.doIsWriteable() returns true.

This implementation throws an exception.

Overrides:

doRename in class AbstractFileObject<HdfsFileSystem>

Parameters:

newfile - A FileObject with the new file name.

Throws:

Exception - if an error occurs.

Since:

2.7.0

See Also:

AbstractFileObject.doRename(FileObject)

doSetAttribute

protected void doSetAttribute(String attrName,
                              Object value)
                       throws Exception

Description copied from class: AbstractFileObject

Sets an attribute of this file.

Is only called if AbstractFileObject.doGetType() does not return FileType.IMAGINARY.

This implementation throws an exception.

Overrides:

doSetAttribute in class AbstractFileObject<HdfsFileSystem>

Parameters:

attrName - The attribute name.

value - The value to be associated with the attribute name.

Throws:

Exception - if an error occurs.

See Also:

AbstractFileObject.doSetAttribute(java.lang.String, java.lang.Object)

doSetLastModifiedTime

protected boolean doSetLastModifiedTime(long modtime)
                                 throws Exception

Description copied from class: AbstractFileObject

Sets the last modified time of this file.

Is only called if AbstractFileObject.doGetType() does not return FileType.IMAGINARY.

This implementation throws an exception.

Overrides:

doSetLastModifiedTime in class AbstractFileObject<HdfsFileSystem>

Parameters:

modtime - The last modification time.

Returns:

true if the time was set.

Throws:

Exception - Any Exception thrown is wrapped in FileSystemException.

See Also:

AbstractFileObject.doSetLastModifiedTime(long)

exists

public boolean exists()
               throws FileSystemException

Description copied from class: AbstractFileObject

Determines if the file exists.

Specified by:

exists in interface FileObject

Overrides:

exists in class AbstractFileObject<HdfsFileSystem>

Returns:

boolean true if file exists, false if not

Throws:

FileSystemException - if an error occurs.

See Also:

AbstractFileObject.exists()