自定义了一个similarity问题

[胡椒csdn]

自定义了一个similarity，仿照classicsimilarity写的，代码如下 ，solr版本时5.4.1
public class CustomSimilarity extends TFIDFSimilarity{

@Override
public float coord(int overlap, int maxOverlap) {
return 1/ (float)maxOverlap;
}

@Override
public float decodeNormValue(long arg0) {
return 1;
}

@Override
public long encodeNormValue(float arg0) {
return 1;
}

@Override
public float idf(long docFreq, long numDocs) {
return 1;
}

@Override
public float lengthNorm(FieldInvertState state) {
final int numTerms;
if (discountOverlaps)
numTerms = state.getLength() - state.getNumOverlap();
else
numTerms = state.getLength();
return state.getBoost() * ((float) (1.0 / Math.sqrt(numTerms)));
}

@Override
public float queryNorm(float sumOfSquaredWeights) {
return 1;
}

@Override
public float scorePayload(int doc, int start, int end, BytesRef payload) {
return 1;
}

@Override
public float sloppyFreq(int distance) {
return 1;
}

@Override
public float tf(float freq) {
return 1;
}

protected boolean discountOverlaps = true;



public void setDiscountOverlaps(boolean v) {
discountOverlaps = v;
}

/**
* Returns true if overlap tokens are discounted from the document's length.
* @see #setDiscountOverlaps
*/
public boolean getDiscountOverlaps() {
return discountOverlaps;
}

@Override
public String toString() {
return "CustomSimilarity";
}

}
配置没有问题，但是lengthNorm（）方法一直没有被调用（无论怎么改都不影响得分），请问各位大神什么原因呀？

[胡椒csdn]

lengthNorm（）方法是在创建索引的时候被调用的