Remove tf() painless method (#9995)

Signed-off-by: Louis Chu <clingzhi@amazon.com>

Author: noCharger

modules/lang-painless/src/main/resources/org/opensearch/painless/spi/org.opensearch.score.txt

@@ -24,7 +24,6 @@ class org.opensearch.script.ScoreScript @no_import {
 
 static_import {
     int termFreq(org.opensearch.script.ScoreScript, String, String) bound_to org.opensearch.script.ScoreScriptUtils$TermFreq
-    float tf(org.opensearch.script.ScoreScript, String, String) bound_to org.opensearch.script.ScoreScriptUtils$TF
     long totalTermFreq(org.opensearch.script.ScoreScript, String, String) bound_to org.opensearch.script.ScoreScriptUtils$TotalTermFreq
     long sumTotalTermFreq(org.opensearch.script.ScoreScript, String) bound_to org.opensearch.script.ScoreScriptUtils$SumTotalTermFreq
     double saturation(double, double) from_class org.opensearch.script.ScoreScriptUtils

server/src/main/java/org/opensearch/index/query/functionscore/TermFrequencyFunctionFactory.java

@@ -11,7 +11,6 @@
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.queries.function.FunctionValues;
 import org.apache.lucene.queries.function.valuesource.SumTotalTermFreqValueSource;
-import org.apache.lucene.queries.function.valuesource.TFValueSource;
 import org.apache.lucene.queries.function.valuesource.TermFreqValueSource;
 import org.apache.lucene.queries.function.valuesource.TotalTermFreqValueSource;
 import org.apache.lucene.search.IndexSearcher;
@@ -42,15 +41,6 @@ public static TermFrequencyFunction createFunction(
                 TermFreqValueSource termFreqValueSource = new TermFreqValueSource(field, term, field, BytesRefs.toBytesRef(term));
                 FunctionValues functionValues = termFreqValueSource.getValues(null, readerContext);
                 return docId -> functionValues.intVal(docId);
-            case TF:
-                TFValueSource tfValueSource = new TFValueSource(field, term, field, BytesRefs.toBytesRef(term));
-                Map<Object, Object> tfContext = new HashMap<>() {
-                    {
-                        put("searcher", indexSearcher);
-                    }
-                };
-                functionValues = tfValueSource.getValues(tfContext, readerContext);
-                return docId -> functionValues.floatVal(docId);
             case TOTAL_TERM_FREQ:
                 TotalTermFreqValueSource totalTermFreqValueSource = new TotalTermFreqValueSource(
                     field,
@@ -78,7 +68,6 @@ public static TermFrequencyFunction createFunction(
      */
     public enum TermFrequencyFunctionName {
         TERM_FREQ("termFreq"),
-        TF("tf"),
         TOTAL_TERM_FREQ("totalTermFreq"),
         SUM_TOTAL_TERM_FREQ("sumTotalTermFreq");
 

server/src/main/java/org/opensearch/script/ScoreScriptUtils.java

@@ -50,7 +50,6 @@
 import static org.opensearch.common.util.BitMixer.mix32;
 import static org.opensearch.index.query.functionscore.TermFrequencyFunctionFactory.TermFrequencyFunctionName.SUM_TOTAL_TERM_FREQ;
 import static org.opensearch.index.query.functionscore.TermFrequencyFunctionFactory.TermFrequencyFunctionName.TERM_FREQ;
-import static org.opensearch.index.query.functionscore.TermFrequencyFunctionFactory.TermFrequencyFunctionName.TF;
 import static org.opensearch.index.query.functionscore.TermFrequencyFunctionFactory.TermFrequencyFunctionName.TOTAL_TERM_FREQ;
 
 /**
@@ -95,27 +94,6 @@ public int termFreq(String field, String term) {
         }
     }
 
-    /**
-     * Calculates the term frequency-inverse document frequency (tf-idf) for a specific term within a field.
-     *
-     * @opensearch.internal
-     */
-    public static final class TF {
-        private final ScoreScript scoreScript;
-
-        public TF(ScoreScript scoreScript) {
-            this.scoreScript = scoreScript;
-        }
-
-        public float tf(String field, String term) {
-            try {
-                return (float) scoreScript.getTermFrequency(TF, field, term);
-            } catch (Exception e) {
-                throw ExceptionsHelper.convertToOpenSearchException(e);
-            }
-        }
-    }
-
     /**
      * Retrieves the total term frequency within a field for a specific term.
      *