org.apache.commons.vfs2.provider.hdfs

Class HdfsRandomAccessContent

java.lang.Object

org.apache.commons.vfs2.provider.AbstractRandomAccessContent

org.apache.commons.vfs2.provider.hdfs.HdfsRandomAccessContent

All Implemented Interfaces:

Closeable, DataInput, DataOutput, AutoCloseable, RandomAccessContent

public class HdfsRandomAccessContent
extends AbstractRandomAccessContent

Provides random access to content in an HdfsFileObject. Currently this only supports read operations. All write operations throw an UnsupportedOperationException.

Since:

2.1

Constructor Summary

Constructors

Constructor and Description
HdfsRandomAccessContent(org.apache.hadoop.fs.Path path, org.apache.hadoop.fs.FileSystem fs) Create random access content.

Method Summary

Modifier and Type	Method and Description
void	close() Closes this random access file stream and releases any system resources associated with the stream.
long	getFilePointer() Returns the current offset in this file.
InputStream	getInputStream() Get the input stream.
long	length() Returns the length of this file.
boolean	readBoolean()
byte	readByte()
char	readChar()
double	readDouble()
float	readFloat()
void	readFully(byte[] b)
void	readFully(byte[] b, int off, int len)
int	readInt()
String	readLine()
long	readLong()
short	readShort()
int	readUnsignedByte()
int	readUnsignedShort()
String	readUTF()
void	seek(long pos) Sets the file-pointer offset, measured from the beginning of this file, at which the next read or write occurs.
void	setLength(long newLength) Sets the length of this content.
int	skipBytes(int n)

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

write, write, write, writeBoolean, writeByte, writeBytes, writeChar, writeChars, writeDouble, writeFloat, writeInt, writeLong, writeShort, writeUTF

Methods inherited from class java.lang.Object

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

Constructor Detail

HdfsRandomAccessContent

public HdfsRandomAccessContent(org.apache.hadoop.fs.Path path,
                               org.apache.hadoop.fs.FileSystem fs)
                        throws IOException

Create random access content.

Parameters:

path - A Hadoop Path

fs - A Hadoop FileSystem

Throws:

IOException - when the path cannot be processed.

Method Detail

close

public void close()
           throws IOException

Description copied from interface: RandomAccessContent

Closes this random access file stream and releases any system resources associated with the stream.

A closed random access file cannot perform input or output operations and cannot be reopened.

If this file has an associated channel then the channel is closed as well.

Throws:

IOException - if an I/O error occurs.

See Also:

RandomAccessContent.close()

getFilePointer

public long getFilePointer()
                    throws IOException

Description copied from interface: RandomAccessContent

Returns the current offset in this file.

Returns:

the offset from the beginning of the file, in bytes, at which the next read or write occurs.

Throws:

IOException - if an I/O error occurs.

See Also:

RandomAccessContent.getFilePointer()

getInputStream

public InputStream getInputStream()
                           throws IOException

Description copied from interface: RandomAccessContent

Get the input stream.

Notice: If you use RandomAccessContent.seek(long) you have to re-get the InputStream

Returns:

the InputStream.

Throws:

IOException - if an I/O error occurs.

See Also:

RandomAccessContent.getInputStream()

length

public long length()
            throws IOException

Description copied from interface: RandomAccessContent

Returns the length of this file.

Returns:

the length of this file, measured in bytes.

Throws:

IOException - if an I/O error occurs.

See Also:

RandomAccessContent.length()

readBoolean

public boolean readBoolean()
                    throws IOException

Throws:

IOException

See Also:

DataInput.readBoolean()

readByte

public byte readByte()
              throws IOException

Throws:

IOException

See Also:

DataInput.readByte()

readChar

public char readChar()
              throws IOException

Throws:

IOException

See Also:

DataInput.readChar()

readDouble

public double readDouble()
                  throws IOException

Throws:

IOException

See Also:

DataInput.readDouble()

readFloat

public float readFloat()
                throws IOException

Throws:

IOException

See Also:

DataInput.readFloat()

readFully

public void readFully(byte[] b)
               throws IOException

Throws:

IOException

See Also:

DataInput.readFully(byte[])

readFully

public void readFully(byte[] b,
                      int off,
                      int len)
               throws IOException

Throws:

IOException

See Also:

DataInput.readFully(byte[], int, int)

readInt

public int readInt()
            throws IOException

Throws:

IOException

See Also:

DataInput.readInt()

readLine

public String readLine()
                throws IOException

Specified by:

readLine in interface DataInput

Overrides:

readLine in class AbstractRandomAccessContent

Returns:

The line as a String.

Throws:

IOException - if an error occurs.

See Also:

DataInput.readLine()

readLong

public long readLong()
              throws IOException

Throws:

IOException

See Also:

DataInput.readLong()

readShort

public short readShort()
                throws IOException

Throws:

IOException

See Also:

DataInput.readShort()

readUnsignedByte

public int readUnsignedByte()
                     throws IOException

Throws:

IOException

See Also:

DataInput.readUnsignedByte()

readUnsignedShort

public int readUnsignedShort()
                      throws IOException

Throws:

IOException

See Also:

DataInput.readUnsignedShort()

readUTF

public String readUTF()
               throws IOException

Throws:

IOException

See Also:

DataInput.readUTF()

seek

public void seek(long pos)
          throws IOException

Description copied from interface: RandomAccessContent

Sets the file-pointer offset, measured from the beginning of this file, at which the next read or write occurs.

The offset may be set beyond the end of the file. Setting the offset beyond the end of the file does not change the file length. The file length will change only by writing after the offset has been set beyond the end of the file.

Notice: If you use RandomAccessContent.getInputStream() you have to re-get the InputStream after calling RandomAccessContent.seek(long)

Parameters:

pos - the offset position, measured in bytes from the beginning of the file, at which to set the file pointer.

Throws:

IOException - if pos is less than 0 or if an I/O error occurs.

See Also:

RandomAccessContent.seek(long)

setLength

public void setLength(long newLength)
               throws IOException

Description copied from interface: RandomAccessContent

Sets the length of this content.

If the the newLength argument is smaller than RandomAccessContent.length(), the content is truncated.

If the the newLength argument is greater than RandomAccessContent.length(), the content grows with undefined data.

Parameters:

newLength - The desired content length

Throws:

IOException - If an I/O error occurs

See Also:

RandomAccessContent.setLength(long)

skipBytes

public int skipBytes(int n)
              throws IOException

Throws:

IOException

See Also:

DataInput.skipBytes(int)