org.apache.nutch.io
Class SequenceFile.Reader

java.lang.Object
  org.apache.nutch.io.SequenceFile.Reader

Enclosing class:

SequenceFile

public static class SequenceFile.Reader

extends Object

Writes key/value pairs from a sequence-format file.

Constructor Summary

SequenceFile.Reader(NutchFileSystem nfs, String file)
Open the named file.

Method Summary

void	close() Close the file.
Class	getKeyClass() Returns the class of keys in this file.
long	getPosition() Return the current byte position in the input file.
Class	getValueClass() Returns the class of values in this file.
int	next(DataOutputBuffer buffer) Read the next key/value pair in the file into buffer.
boolean	next(Writable key) Read the next key in the file into key, skipping its value.
boolean	next(Writable key, Writable val) Read the next key/value pair in the file into key and val.
void	seek(long position) Set the current byte position in the input file.
void	sync(long position) Seek to the next sync mark past a given position.
boolean	syncSeen() Returns true iff the previous call to next passed a sync mark.
String	toString() Returns the name of the file.

Methods inherited from class java.lang.Object

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

Constructor Detail

SequenceFile.Reader

public SequenceFile.Reader(NutchFileSystem nfs,
                           String file)
                    throws IOException

Open the named file.

Method Detail

close

public void close()
           throws IOException

Close the file.

Throws:

IOException

getKeyClass

public Class getKeyClass()

Returns the class of keys in this file.

getValueClass

public Class getValueClass()

Returns the class of values in this file.

next

public boolean next(Writable key)
             throws IOException

Read the next key in the file into key, skipping its value. True if another entry exists, and false at end of file.

Throws:

IOException

next

public boolean next(Writable key,
                    Writable val)
             throws IOException

Read the next key/value pair in the file into key and val. Returns true if such a pair exists and false when at end of file

Throws:

IOException

next

public int next(DataOutputBuffer buffer)
         throws IOException

Read the next key/value pair in the file into buffer. Returns the length of the key read, or -1 if at end of file. The length of the value may be computed by calling buffer.getLength() before and after calls to this method.

Throws:

IOException

seek

public void seek(long position)
          throws IOException

Set the current byte position in the input file.

Throws:

IOException

sync

public void sync(long position)
          throws IOException

Seek to the next sync mark past a given position.

Throws:

IOException

syncSeen

public boolean syncSeen()

Returns true iff the previous call to next passed a sync mark.

getPosition

public long getPosition()
                 throws IOException

Return the current byte position in the input file.

Throws:

IOException

toString

public String toString()

Returns the name of the file.