org.apache.lucene.analysis.charfilter
Class BaseCharFilter

java.lang.Object
  extended by java.io.Reader
      extended by org.apache.lucene.analysis.CharFilter
          extended by org.apache.lucene.analysis.charfilter.BaseCharFilter
All Implemented Interfaces:
Closeable, Readable
Direct Known Subclasses:
HTMLStripCharFilter, MappingCharFilter, PatternReplaceCharFilter

public abstract class BaseCharFilter
extends CharFilter

Base utility class for implementing a CharFilter. You subclass this, and then record mappings by calling addOffCorrectMap(int, int), and then invoke the correct method to correct an offset.


Field Summary
 
Fields inherited from class org.apache.lucene.analysis.CharFilter
input
 
Fields inherited from class java.io.Reader
lock
 
Constructor Summary
BaseCharFilter(Reader in)
           
 
Method Summary
protected  void addOffCorrectMap(int off, int cumulativeDiff)
           Adds an offset correction mapping at the given output stream offset.
protected  int correct(int currentOff)
          Retrieve the corrected offset.
protected  int getLastCumulativeDiff()
           
 
Methods inherited from class org.apache.lucene.analysis.CharFilter
close, correctOffset
 
Methods inherited from class java.io.Reader
mark, markSupported, read, read, read, read, ready, reset, skip
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

BaseCharFilter

public BaseCharFilter(Reader in)
Method Detail

correct

protected int correct(int currentOff)
Retrieve the corrected offset.

Specified by:
correct in class CharFilter

getLastCumulativeDiff

protected int getLastCumulativeDiff()

addOffCorrectMap

protected void addOffCorrectMap(int off,
                                int cumulativeDiff)

Adds an offset correction mapping at the given output stream offset.

Assumption: the offset given with each successive call to this method will not be smaller than the offset given at the previous invocation.

Parameters:
off - The output stream offset at which to apply the correction
cumulativeDiff - The input offset is given by adding this to the output offset


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