org.apache.nutch.io
Class SetFile.Reader

java.lang.Object
  org.apache.nutch.io.MapFile.Reader
      org.apache.nutch.io.SetFile.Reader

Enclosing class:

SetFile

public static class SetFile.Reader

extends MapFile.Reader

Provide access to an existing set file.

Constructor Summary

SetFile.Reader(NutchFileSystem nfs, String dirName)
Construct a set reader for the named set.

SetFile.Reader(NutchFileSystem nfs, String dirName, WritableComparator comparator)
Construct a set reader for the named set using the named comparator.

Method Summary

WritableComparable	get(WritableComparable key) Read the matching key from a set into key.
boolean	next(WritableComparable key) Read the next key in a set into key.
boolean	seek(WritableComparable key) Positions the reader at the named key, or if none such exists, at the first entry after the named key.

Methods inherited from class org.apache.nutch.io.MapFile.Reader

close, finalKey, get, getKeyClass, getValueClass, next, reset

Methods inherited from class java.lang.Object

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

Constructor Detail

SetFile.Reader

public SetFile.Reader(NutchFileSystem nfs,
                      String dirName)
               throws IOException

Construct a set reader for the named set.

SetFile.Reader

public SetFile.Reader(NutchFileSystem nfs,
                      String dirName,
                      WritableComparator comparator)
               throws IOException

Construct a set reader for the named set using the named comparator.

Method Detail

seek

public boolean seek(WritableComparable key)
             throws IOException

Description copied from class: MapFile.Reader

Positions the reader at the named key, or if none such exists, at the first entry after the named key. Returns true iff the named key exists in this map.

Overrides:

seek in class MapFile.Reader

Throws:

IOException

next

public boolean next(WritableComparable key)
             throws IOException

Read the next key in a set into key. Returns true if such a key exists and false when at the end of the set.

Throws:

IOException

get

public WritableComparable get(WritableComparable key)
                       throws IOException

Read the matching key from a set into key. Returns key, or null if no match exists.

Throws:

IOException