org.apache.avro.file
Class DataFileReader<D>

java.lang.Object
  org.apache.avro.file.DataFileStream<D>
      org.apache.avro.file.DataFileReader<D>

All Implemented Interfaces:

Closeable, Iterable<D>, Iterator<D>, FileReader<D>

public class DataFileReader<D>
extends DataFileStream<D>
implements FileReader<D>

Random access to files written with DataFileWriter.

See Also:

DataFileWriter

Constructor Summary

DataFileReader(File file, DatumReader<D> reader)
Construct a reader for a file.

DataFileReader(SeekableInput sin, DatumReader<D> reader)
Construct a reader for a file.

Method Summary

protected void	blockFinished()
boolean	pastSync(long position) Return true if past the next synchronization point after a position.
long	previousSync() Return the last synchronization point before our current position.
void	seek(long position) Move to a specific, known synchronization point, one returned from DataFileWriter.sync() while writing.
void	sync(long position) Move to the next synchronization point after a position.
long	tell() Return the current position in the input.

Methods inherited from class org.apache.avro.file.DataFileStream

close, getBlockCount, getMeta, getMetaLong, getMetaString, getSchema, hasNext, iterator, next, next, nextBlock, remove

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.avro.file.FileReader

getSchema, next

Methods inherited from interface java.util.Iterator

hasNext, next, remove

Methods inherited from interface java.lang.Iterable

iterator

Methods inherited from interface java.io.Closeable

close

Constructor Detail

DataFileReader

public DataFileReader(File file,
                      DatumReader<D> reader)
               throws IOException

Construct a reader for a file.

Throws:

IOException

DataFileReader

public DataFileReader(SeekableInput sin,
                      DatumReader<D> reader)
               throws IOException

Construct a reader for a file.

Throws:

IOException

Method Detail

seek

public void seek(long position)
          throws IOException

Move to a specific, known synchronization point, one returned from DataFileWriter.sync() while writing. If synchronization points were not saved while writing a file, use {#sync(long)} instead.

Throws:

IOException

sync

public void sync(long position)
          throws IOException

Move to the next synchronization point after a position. To process a range of file entires, call this with the starting position, then check pastSync(long) with the end point before each call to DataFileStream.next().

Specified by:

sync in interface FileReader<D>

Throws:

IOException

blockFinished

protected void blockFinished()
                      throws IOException

Overrides:

blockFinished in class DataFileStream<D>

Throws:

IOException

previousSync

public long previousSync()

Return the last synchronization point before our current position.

pastSync

public boolean pastSync(long position)
                 throws IOException

Return true if past the next synchronization point after a position.

Specified by:

pastSync in interface FileReader<D>

Throws:

IOException

tell

public long tell()
          throws IOException

Description copied from interface: FileReader

Return the current position in the input.

Specified by:

tell in interface FileReader<D>

Throws:

IOException