org.apache.lucene.facet.encoding
Class NOnesIntEncoder

java.lang.Object
  org.apache.lucene.facet.encoding.IntEncoder
      org.apache.lucene.facet.encoding.ChunksIntEncoder
          org.apache.lucene.facet.encoding.FourFlagsIntEncoder
              org.apache.lucene.facet.encoding.NOnesIntEncoder

public class NOnesIntEncoder
extends FourFlagsIntEncoder

A variation of FourFlagsIntEncoder which translates the data as follows:

• Values ≥ 2 are trnalsated to value+1 (2 ⇒ 3, 3 ⇒ 4 and so forth).
• Any N occurrences of 1 are encoded as a single 2.
• Otherwise, each 1 is encoded as 1.

Encoding examples:

• N = 4: the data 1,1,1,1,1 is translated to: 2, 1
• N = 3: the data 1,2,3,4,1,1,1,1,5 is translated to 1,3,4,5,2,1,6

NOTE: this encoder does not support values ≤ 0 and Integer.MAX_VALUE. 0 is not supported because it's not supported by FourFlagsIntEncoder and Integer.MAX_VALUE because this encoder translates N to N+1, which will cause an overflow and Integer.MAX_VALUE will become a negative number, which is not supported as well.
This does not mean you cannot encode Integer.MAX_VALUE. If it is not the first value to encode, and you wrap this encoder with DGapIntEncoder, then the value that will be sent to this encoder will be MAX_VAL - prev.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Field Summary

Fields inherited from class org.apache.lucene.facet.encoding.ChunksIntEncoder

encodeQueue, indicator, ordinal

Constructor Summary

NOnesIntEncoder(int n)
Constructs an encoder with a given value of N (N: Number of consecutive '1's to be translated into single target value '2').

Method Summary

IntDecoder	createMatchingDecoder() Returns an IntDecoder which can decode the values that were encoded with this encoder.
void	encode(IntsRef values, BytesRef buf) Encodes the values to the given buffer.
String	toString()

Methods inherited from class org.apache.lucene.facet.encoding.ChunksIntEncoder

encodeChunk

Methods inherited from class java.lang.Object

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

Constructor Detail

NOnesIntEncoder

public NOnesIntEncoder(int n)

Constructs an encoder with a given value of N (N: Number of consecutive '1's to be translated into single target value '2').

Method Detail

encode

public void encode(IntsRef values,
                   BytesRef buf)

Description copied from class: IntEncoder

Encodes the values to the given buffer. Note that the buffer's offset and length are set to 0.

Overrides:

encode in class FourFlagsIntEncoder

createMatchingDecoder

public IntDecoder createMatchingDecoder()

Description copied from class: IntEncoder

Returns an IntDecoder which can decode the values that were encoded with this encoder.

Overrides:

createMatchingDecoder in class FourFlagsIntEncoder

toString

public String toString()

Overrides:

toString in class FourFlagsIntEncoder