LUCENE-7876 avoid leafReader.fields

lucene/CHANGES.txt

@@ -145,6 +145,10 @@ Other
   from methods that don't declare them ("sneaky throw" hack). (Robert Muir,
   Uwe Schindler, Dawid Weiss)
 
+* LUCENE-7876: Avoid calls to LeafReader.fields() and MultiFields.getFields()
+  that are trivially replaced by LeafReader.terms() and MultiFields.getTerms()
+  (David Smiley)
+
 Improvements
 
 * LUCENE-7841: Normalize ґ to г in Ukrainian analyzer. (Andriy Rysin via Dawid Weiss)

lucene/backward-codecs/src/test/org/apache/lucene/index/TestBackwardsCompatibility.java

@@ -1192,7 +1192,7 @@ public class TestBackwardsCompatibility extends LuceneTestCase {
     for (String name : oldNames) {
       Directory dir = oldIndexDirs.get(name);
       IndexReader r = DirectoryReader.open(dir);
-      TermsEnum terms = MultiFields.getFields(r).terms("content").iterator();
+      TermsEnum terms = MultiFields.getTerms(r, "content").iterator();
       BytesRef t = terms.next();
       assertNotNull(t);
 

lucene/core/src/java/org/apache/lucene/index/BufferedUpdatesStream.java

@@ -501,9 +501,8 @@ class BufferedUpdatesStream implements Accountable {
         queue = new SegmentQueue(numReaders);
 
         long segTermCount = 0;
-        for(int i=0;i<numReaders;i++) {
+        for (SegmentState state : segStates) {
-          SegmentState state = segStates[i];
+          Terms terms = state.reader.terms(field);
-          Terms terms = state.reader.fields().terms(field);
           if (terms != null) {
             segTermCount += terms.size();
             state.termsEnum = terms.iterator();
@@ -617,7 +616,6 @@ class BufferedUpdatesStream implements Accountable {
   // DocValues updates
   private synchronized void applyDocValuesUpdates(List<DocValuesUpdate> updates, 
       SegmentState segState, DocValuesFieldUpdates.Container dvUpdatesContainer) throws IOException {
-    Fields fields = segState.reader.fields();
 
     // TODO: we can process the updates per DV field, from last to first so that
     // if multiple terms affect same document for the same field, we add an update
@@ -651,7 +649,7 @@ class BufferedUpdatesStream implements Accountable {
         // if we change the code to process updates in terms order, enable this assert
 //        assert currentField == null || currentField.compareTo(term.field()) < 0;
         currentField = term.field();
-        Terms terms = fields.terms(currentField);
+        Terms terms = segState.reader.terms(currentField);
         if (terms != null) {
           termsEnum = terms.iterator();
         } else {

lucene/core/src/java/org/apache/lucene/search/TermInSetQuery.java

@@ -26,7 +26,6 @@ import java.util.Objects;
 import java.util.Set;
 import java.util.SortedSet;
 
-import org.apache.lucene.index.Fields;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.LeafReaderContext;
@@ -224,8 +223,7 @@ public class TermInSetQuery extends Query implements Accountable {
       private WeightOrDocIdSet rewrite(LeafReaderContext context) throws IOException {
         final LeafReader reader = context.reader();
 
-        final Fields fields = reader.fields();
+        Terms terms = reader.terms(field);
-        Terms terms = fields.terms(field);
         if (terms == null) {
           return null;
         }

lucene/core/src/test/org/apache/lucene/codecs/lucene50/TestBlockPostingsFormat.java

@@ -55,7 +55,7 @@ public class TestBlockPostingsFormat extends BasePostingsFormatTestCase {
 
     DirectoryReader r = DirectoryReader.open(w);
     assertEquals(1, r.leaves().size());
-    FieldReader field = (FieldReader) r.leaves().get(0).reader().fields().terms("field");
+    FieldReader field = (FieldReader) r.leaves().get(0).reader().terms("field");
     // We should see exactly two blocks: one root block (prefix empty string) and one block for z* terms (prefix z):
     Stats stats = field.getStats();
     assertEquals(0, stats.floorBlockCount);

lucene/core/src/test/org/apache/lucene/index/Test2BDocs.java

@@ -91,7 +91,7 @@ public class Test2BDocs extends LuceneTestCase {
       LeafReader reader = context.reader();
       int lim = context.reader().maxDoc();
 
-      Terms terms = reader.fields().terms("f1");
+      Terms terms = reader.terms("f1");
       for (int i=0; i<10000; i++) {
         TermsEnum te = terms.iterator();
         assertTrue( te.seekExact(term) );

lucene/core/src/test/org/apache/lucene/index/TestDoc.java

@@ -249,14 +249,16 @@ public class TestDoc extends LuceneTestCase {
     for (int i = 0; i < reader.numDocs(); i++)
       out.println(reader.document(i));
 
-    Fields fields = reader.fields();
+    for (FieldInfo fieldInfo : reader.getFieldInfos()) {
-    for (String field : fields)  {
+      if (fieldInfo.getIndexOptions() == IndexOptions.NONE) {
-      Terms terms = fields.terms(field);
+        continue;
+      }
+      Terms terms = reader.terms(fieldInfo.name);
       assertNotNull(terms);
       TermsEnum tis = terms.iterator();
       while(tis.next() != null) {
 
-        out.print("  term=" + field + ":" + tis.term());
+        out.print("  term=" + fieldInfo.name + ":" + tis.term());
         out.println("    DF=" + tis.docFreq());
 
         PostingsEnum positions = tis.postings(null, PostingsEnum.POSITIONS);

lucene/core/src/test/org/apache/lucene/index/TestFlex.java

@@ -17,10 +17,13 @@
 package org.apache.lucene.index;
 
 
-import org.apache.lucene.store.*;
+import org.apache.lucene.analysis.MockAnalyzer;
-import org.apache.lucene.analysis.*;
+import org.apache.lucene.document.Document;
-import org.apache.lucene.document.*;
+import org.apache.lucene.document.Field;
-import org.apache.lucene.util.*;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.LuceneTestCase;
+import org.apache.lucene.util.TestUtil;
 
 public class TestFlex extends LuceneTestCase {
 
@@ -70,7 +73,7 @@ public class TestFlex extends LuceneTestCase {
     w.addDocument(doc);
     w.forceMerge(1);
     DirectoryReader r = w.getReader();
-    TermsEnum terms = getOnlyLeafReader(r).fields().terms("f").iterator();
+    TermsEnum terms = getOnlyLeafReader(r).terms("f").iterator();
     assertTrue(terms.next() != null);
     try {
       assertEquals(0, terms.ord());

lucene/core/src/test/org/apache/lucene/index/TestIndexReaderClose.java

@@ -80,9 +80,7 @@ public class TestIndexReaderClose extends LuceneTestCase {
         reader.getReaderCacheHelper().addClosedListener(new FaultyListener());
       }
 
-      IllegalStateException expected = expectThrows(IllegalStateException.class, () -> {
+      IllegalStateException expected = expectThrows(IllegalStateException.class, () -> reader.close());
-        reader.close();
-      });
 
       if (throwOnClose) {
         assertEquals("BOOM!", expected.getMessage());
@@ -90,9 +88,7 @@ public class TestIndexReaderClose extends LuceneTestCase {
         assertEquals("GRRRRRRRRRRRR!", expected.getMessage());
       }
 
-      expectThrows(AlreadyClosedException.class, () -> {
+      expectThrows(AlreadyClosedException.class, () -> reader.terms("someField"));
-        reader.fields();
-      });
 
       if (random().nextBoolean()) {
         reader.close(); // call it again

lucene/core/src/test/org/apache/lucene/index/TestIndexWriter.java

@@ -694,7 +694,7 @@ public class TestIndexWriter extends LuceneTestCase {
     writer.close();
     DirectoryReader reader = DirectoryReader.open(dir);
     LeafReader subreader = getOnlyLeafReader(reader);
-    TermsEnum te = subreader.fields().terms("").iterator();
+    TermsEnum te = subreader.terms("").iterator();
     assertEquals(new BytesRef("a"), te.next());
     assertEquals(new BytesRef("b"), te.next());
     assertEquals(new BytesRef("c"), te.next());
@@ -715,7 +715,7 @@ public class TestIndexWriter extends LuceneTestCase {
     writer.close();
     DirectoryReader reader = DirectoryReader.open(dir);
     LeafReader subreader = getOnlyLeafReader(reader);
-    TermsEnum te = subreader.fields().terms("").iterator();
+    TermsEnum te = subreader.terms("").iterator();
     assertEquals(new BytesRef(""), te.next());
     assertEquals(new BytesRef("a"), te.next());
     assertEquals(new BytesRef("b"), te.next());

lucene/core/src/test/org/apache/lucene/index/TestIndexWriterUnicode.java

@@ -136,7 +136,7 @@ public class TestIndexWriterUnicode extends LuceneTestCase {
   }
 
   private void checkTermsOrder(IndexReader r, Set<String> allTerms, boolean isTop) throws IOException {
-    TermsEnum terms = MultiFields.getFields(r).terms("f").iterator();
+    TermsEnum terms = MultiFields.getTerms(r, "f").iterator();
 
     BytesRefBuilder last = new BytesRefBuilder();
 

lucene/core/src/test/org/apache/lucene/index/TestPayloads.java

@@ -479,7 +479,7 @@ public class TestPayloads extends LuceneTestCase {
     }
     writer.close();
     IndexReader reader = DirectoryReader.open(dir);
-    TermsEnum terms = MultiFields.getFields(reader).terms(field).iterator();
+    TermsEnum terms = MultiFields.getTerms(reader, field).iterator();
     PostingsEnum tp = null;
     while (terms.next() != null) {
       String termText = terms.term().utf8ToString();
@@ -602,7 +602,7 @@ public class TestPayloads extends LuceneTestCase {
     field.setTokenStream(ts);
     writer.addDocument(doc);
     DirectoryReader reader = writer.getReader();
-    TermsEnum te = MultiFields.getFields(reader).terms("field").iterator();
+    TermsEnum te = MultiFields.getTerms(reader, "field").iterator();
     assertTrue(te.seekExact(new BytesRef("withPayload")));
     PostingsEnum de = te.postings(null, PostingsEnum.PAYLOADS);
     de.nextDoc();

lucene/core/src/test/org/apache/lucene/index/TestPerSegmentDeletes.java

@@ -221,9 +221,7 @@ public class TestPerSegmentDeletes extends LuceneTestCase {
 
   public int[] toDocsArray(Term term, Bits bits, IndexReader reader)
       throws IOException {
-    Fields fields = MultiFields.getFields(reader);
+    TermsEnum ctermsEnum = MultiFields.getTerms(reader, term.field).iterator();
-    Terms cterms = fields.terms(term.field);
-    TermsEnum ctermsEnum = cterms.iterator();
     if (ctermsEnum.seekExact(new BytesRef(term.text()))) {
       PostingsEnum postingsEnum = TestUtil.docs(random(), ctermsEnum, null, PostingsEnum.NONE);
       return toArray(postingsEnum);

lucene/core/src/test/org/apache/lucene/index/TestPostingsOffsets.java

@@ -291,7 +291,7 @@ public class TestPostingsOffsets extends LuceneTestCase {
       // TODO: improve this
       LeafReader sub = ctx.reader();
       //System.out.println("\nsub=" + sub);
-      final TermsEnum termsEnum = sub.fields().terms("content").iterator();
+      final TermsEnum termsEnum = sub.terms("content").iterator();
       PostingsEnum docs = null;
       PostingsEnum docsAndPositions = null;
       PostingsEnum docsAndPositionsAndOffsets = null;

lucene/core/src/test/org/apache/lucene/index/TestSegmentTermDocs.java

@@ -57,7 +57,7 @@ public class TestSegmentTermDocs extends LuceneTestCase {
     SegmentReader reader = new SegmentReader(info, Version.LATEST.major, newIOContext(random()));
     assertTrue(reader != null);
 
-    TermsEnum terms = reader.fields().terms(DocHelper.TEXT_FIELD_2_KEY).iterator();
+    TermsEnum terms = reader.terms(DocHelper.TEXT_FIELD_2_KEY).iterator();
     terms.seekCeil(new BytesRef("field"));
     PostingsEnum termDocs = TestUtil.docs(random(), terms, null, PostingsEnum.FREQS);
     if (termDocs.nextDoc() != DocIdSetIterator.NO_MORE_DOCS)    {

lucene/core/src/test/org/apache/lucene/index/TestSegmentTermEnum.java

@@ -19,14 +19,14 @@ package org.apache.lucene.index;
 
 import java.io.IOException;
 
-import org.apache.lucene.document.Field;
-import org.apache.lucene.util.LuceneTestCase;
-import org.apache.lucene.util.BytesRef;
-import org.apache.lucene.util.TestUtil;
 import org.apache.lucene.analysis.MockAnalyzer;
 import org.apache.lucene.document.Document;
+import org.apache.lucene.document.Field;
 import org.apache.lucene.index.IndexWriterConfig.OpenMode;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.LuceneTestCase;
+import org.apache.lucene.util.TestUtil;
 
 
 public class TestSegmentTermEnum extends LuceneTestCase {
@@ -80,7 +80,7 @@ public class TestSegmentTermEnum extends LuceneTestCase {
     addDoc(writer, "aaa bbb");
     writer.close();
     LeafReader reader = getOnlyLeafReader(DirectoryReader.open(dir));
-    TermsEnum terms = reader.fields().terms("content").iterator();
+    TermsEnum terms = reader.terms("content").iterator();
     assertNotNull(terms.next());
     assertEquals("aaa", terms.term().utf8ToString());
     assertNotNull(terms.next());

lucene/core/src/test/org/apache/lucene/index/TestStressAdvance.java

@@ -21,10 +21,13 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 
-import org.apache.lucene.util.*;
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.Field;
 import org.apache.lucene.search.DocIdSetIterator;
-import org.apache.lucene.store.*;
+import org.apache.lucene.store.Directory;
-import org.apache.lucene.document.*;
+import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.LuceneTestCase;
+import org.apache.lucene.util.TestUtil;
 
 public class TestStressAdvance extends LuceneTestCase {
 
@@ -74,7 +77,7 @@ public class TestStressAdvance extends LuceneTestCase {
           bDocIDs.add(docID);
         }
       }
-      final TermsEnum te = getOnlyLeafReader(r).fields().terms("field").iterator();
+      final TermsEnum te = getOnlyLeafReader(r).terms("field").iterator();
       
       PostingsEnum de = null;
       for(int iter2=0;iter2<10;iter2++) {

lucene/core/src/test/org/apache/lucene/index/TestTermsEnum.java

@@ -18,7 +18,17 @@ package org.apache.lucene.index;
 
 
 import java.io.IOException;
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Random;
+import java.util.Set;
+import java.util.TreeSet;
 
 import org.apache.lucene.analysis.MockAnalyzer;
 import org.apache.lucene.document.Document;
@@ -738,7 +748,7 @@ public class TestTermsEnum extends LuceneTestCase {
     DirectoryReader r = w.getReader();
     w.close();
     LeafReader sub = getOnlyLeafReader(r);
-    Terms terms = sub.fields().terms("field");
+    Terms terms = sub.terms("field");
     Automaton automaton = new RegExp(".*", RegExp.NONE).toAutomaton();
     CompiledAutomaton ca = new CompiledAutomaton(automaton, false, false);    
     TermsEnum te = terms.intersect(ca, null);
@@ -792,7 +802,7 @@ public class TestTermsEnum extends LuceneTestCase {
     DirectoryReader r = w.getReader();
     w.close();
     LeafReader sub = getOnlyLeafReader(r);
-    Terms terms = sub.fields().terms("field");
+    Terms terms = sub.terms("field");
 
     Automaton automaton = new RegExp(".*d", RegExp.NONE).toAutomaton();
     CompiledAutomaton ca = new CompiledAutomaton(automaton, false, false);    
@@ -846,7 +856,7 @@ public class TestTermsEnum extends LuceneTestCase {
     DirectoryReader r = w.getReader();
     w.close();
     LeafReader sub = getOnlyLeafReader(r);
-    Terms terms = sub.fields().terms("field");
+    Terms terms = sub.terms("field");
 
     Automaton automaton = new RegExp(".*", RegExp.NONE).toAutomaton();  // accept ALL
     CompiledAutomaton ca = new CompiledAutomaton(automaton, false, false);    
@@ -986,7 +996,7 @@ public class TestTermsEnum extends LuceneTestCase {
       w.addDocument(doc);
       IndexReader r = w.getReader();
       assertEquals(1, r.leaves().size());
-      TermsEnum te = r.leaves().get(0).reader().fields().terms("field").iterator();
+      TermsEnum te = r.leaves().get(0).reader().terms("field").iterator();
       for(int i=0;i<=termCount;i++) {
         assertTrue("term '" + termsList.get(i).utf8ToString() + "' should exist but doesn't", te.seekExact(termsList.get(i)));
       }
@@ -1007,9 +1017,8 @@ public class TestTermsEnum extends LuceneTestCase {
     doc.add(newStringField("field", "foobar", Field.Store.NO));
     w.addDocument(doc);
     IndexReader r = w.getReader();
-    Fields fields = MultiFields.getFields(r);
+    Terms terms = MultiFields.getTerms(r, "field");
     CompiledAutomaton automaton = new CompiledAutomaton(new RegExp("do_not_match_anything").toAutomaton());
-    Terms terms = fields.terms("field");
     String message = expectThrows(IllegalArgumentException.class, () -> {terms.intersect(automaton, null);}).getMessage();
     assertEquals("please use CompiledAutomaton.getTermsEnum instead", message);
     r.close();

lucene/core/src/test/org/apache/lucene/search/TestMultiPhraseQuery.java

@@ -71,7 +71,7 @@ public class TestMultiPhraseQuery extends LuceneTestCase {
     
     // this TermEnum gives "piccadilly", "pie" and "pizza".
     String prefix = "pi";
-    TermsEnum te = MultiFields.getFields(reader).terms("body").iterator();
+    TermsEnum te = MultiFields.getTerms(reader,"body").iterator();
     te.seekCeil(new BytesRef(prefix));
     do {
       String s = te.term().utf8ToString();

lucene/core/src/test/org/apache/lucene/search/TestPhrasePrefixQuery.java

@@ -73,7 +73,7 @@ public class TestPhrasePrefixQuery extends LuceneTestCase {
     
     // this TermEnum gives "piccadilly", "pie" and "pizza".
     String prefix = "pi";
-    TermsEnum te = MultiFields.getFields(reader).terms("body").iterator();
+    TermsEnum te = MultiFields.getTerms(reader, "body").iterator();
     te.seekCeil(new BytesRef(prefix));
     do {
       String s = te.term().utf8ToString();

lucene/core/src/test/org/apache/lucene/search/TestSameScoresWithThreads.java

@@ -61,7 +61,7 @@ public class TestSameScoresWithThreads extends LuceneTestCase {
     w.close();
 
     final IndexSearcher s = newSearcher(r);
-    Terms terms = MultiFields.getFields(r).terms("body");
+    Terms terms = MultiFields.getTerms(r, "body");
     int termCount = 0;
     TermsEnum termsEnum = terms.iterator();
     while(termsEnum.next() != null) {

lucene/memory/src/test/org/apache/lucene/index/memory/TestMemoryIndex.java

@@ -131,7 +131,7 @@ public class TestMemoryIndex extends LuceneTestCase {
     mi.addField("field", "some terms be here", analyzer);
     IndexSearcher searcher = mi.createSearcher();
     LeafReader reader = (LeafReader) searcher.getIndexReader();
-    TermsEnum terms = reader.fields().terms("field").iterator();
+    TermsEnum terms = reader.terms("field").iterator();
     terms.seekExact(0);
     assertEquals("be", terms.term().utf8ToString());
     TestUtil.checkReader(reader);

lucene/memory/src/test/org/apache/lucene/index/memory/TestMemoryIndexAgainstRAMDir.java

@@ -53,7 +53,6 @@ import org.apache.lucene.document.SortedSetDocValuesField;
 import org.apache.lucene.document.StringField;
 import org.apache.lucene.document.TextField;
 import org.apache.lucene.index.*;
-import org.apache.lucene.index.NumericDocValues;
 import org.apache.lucene.queryparser.classic.QueryParser;
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.search.IndexSearcher;
@@ -67,8 +66,8 @@ import org.apache.lucene.search.spans.SpanOrQuery;
 import org.apache.lucene.search.spans.SpanQuery;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.RAMDirectory;
-import org.apache.lucene.util.ByteBlockPool.Allocator;
 import org.apache.lucene.util.ByteBlockPool;
+import org.apache.lucene.util.ByteBlockPool.Allocator;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.IOUtils;
 import org.apache.lucene.util.LineFileDocs;
@@ -171,7 +170,7 @@ public class TestMemoryIndexAgainstRAMDir extends BaseTokenStreamTestCase {
 
   private void duellReaders(CompositeReader other, LeafReader memIndexReader)
       throws IOException {
-    Fields memFields = memIndexReader.fields();
+    Fields memFields = memIndexReader.getTermVectors(0);
     for (String field : MultiFields.getFields(other)) {
       Terms memTerms = memFields.terms(field);
       Terms iwTerms = memIndexReader.terms(field);

lucene/queries/src/java/org/apache/lucene/queries/CommonTermsQuery.java

@@ -22,7 +22,6 @@ import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
 
-import org.apache.lucene.index.Fields;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.Term;
@@ -214,11 +213,10 @@ public class CommonTermsQuery extends Query {
       Term[] queryTerms) throws IOException {
     TermsEnum termsEnum = null;
     for (LeafReaderContext context : leaves) {
-      final Fields fields = context.reader().fields();
       for (int i = 0; i < queryTerms.length; i++) {
         Term term = queryTerms[i];
         TermContext termContext = contextArray[i];
-        final Terms terms = fields.terms(term.field());
+        final Terms terms = context.reader().terms(term.field());
         if (terms == null) {
           // field does not exist
           continue;

lucene/queries/src/java/org/apache/lucene/queries/function/valuesource/TFValueSource.java

@@ -19,9 +19,8 @@ package org.apache.lucene.queries.function.valuesource;
 import java.io.IOException;
 import java.util.Map;
 
-import org.apache.lucene.index.PostingsEnum;
-import org.apache.lucene.index.Fields;
 import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.PostingsEnum;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermsEnum;
 import org.apache.lucene.queries.function.FunctionValues;
@@ -50,8 +49,7 @@ public class TFValueSource extends TermFreqValueSource {
 
   @Override
   public FunctionValues getValues(Map context, LeafReaderContext readerContext) throws IOException {
-    Fields fields = readerContext.reader().fields();
+    final Terms terms = readerContext.reader().terms(indexedField);
-    final Terms terms = fields.terms(indexedField);
     IndexSearcher searcher = (IndexSearcher)context.get("searcher");
     final TFIDFSimilarity similarity = IDFValueSource.asTFIDF(searcher.getSimilarity(true), indexedField);
     if (similarity == null) {

lucene/queries/src/java/org/apache/lucene/queries/function/valuesource/TermFreqValueSource.java

@@ -19,9 +19,8 @@ package org.apache.lucene.queries.function.valuesource;
 import java.io.IOException;
 import java.util.Map;
 
-import org.apache.lucene.index.PostingsEnum;
-import org.apache.lucene.index.Fields;
 import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.PostingsEnum;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermsEnum;
 import org.apache.lucene.queries.function.FunctionValues;
@@ -48,8 +47,7 @@ public class TermFreqValueSource extends DocFreqValueSource {
 
   @Override
   public FunctionValues getValues(Map context, LeafReaderContext readerContext) throws IOException {
-    Fields fields = readerContext.reader().fields();
+    final Terms terms = readerContext.reader().terms(indexedField);
-    final Terms terms = fields.terms(indexedField);
 
     return new IntDocValues(this) {
       PostingsEnum docs ;

lucene/sandbox/src/test/org/apache/lucene/codecs/idversion/TestIDVersionPostingsFormat.java

@@ -37,12 +37,12 @@ import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.FieldType;
 import org.apache.lucene.index.ConcurrentMergeScheduler;
-import org.apache.lucene.index.PostingsEnum;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.MergeScheduler;
 import org.apache.lucene.index.PerThreadPKLookup;
+import org.apache.lucene.index.PostingsEnum;
 import org.apache.lucene.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.index.TieredMergePolicy;
@@ -75,7 +75,7 @@ public class TestIDVersionPostingsFormat extends LuceneTestCase {
     doc.add(makeIDField("id1", 110));
     w.addDocument(doc);
     IndexReader r = w.getReader();
-    IDVersionSegmentTermsEnum termsEnum = (IDVersionSegmentTermsEnum) r.leaves().get(0).reader().fields().terms("id").iterator();
+    IDVersionSegmentTermsEnum termsEnum = (IDVersionSegmentTermsEnum) r.leaves().get(0).reader().terms("id").iterator();
     assertTrue(termsEnum.seekExact(new BytesRef("id0"), 50));
     assertTrue(termsEnum.seekExact(new BytesRef("id0"), 100));
     assertFalse(termsEnum.seekExact(new BytesRef("id0"), 101));

lucene/test-framework/src/java/org/apache/lucene/index/ThreadedIndexingAndSearchingTestCase.java

@@ -18,7 +18,14 @@ package org.apache.lucene.index;
 
 import java.io.IOException;
 import java.nio.file.Path;
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Random;
+import java.util.Set;
+import java.util.WeakHashMap;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
@@ -349,8 +356,7 @@ public abstract class ThreadedIndexingAndSearchingTestCase extends LuceneTestCas
                   }
                   if (s.getIndexReader().numDocs() > 0) {
                     smokeTestSearcher(s);
-                    Fields fields = MultiFields.getFields(s.getIndexReader());
+                    Terms terms = MultiFields.getTerms(s.getIndexReader(), "body");
-                    Terms terms = fields.terms("body");
                     if (terms == null) {
                       continue;
                     }

solr/core/src/java/org/apache/solr/handler/admin/LukeRequestHandler.java

@@ -16,10 +16,6 @@
  */
 package org.apache.solr.handler.admin;
 
-import static org.apache.lucene.index.IndexOptions.DOCS;
-import static org.apache.lucene.index.IndexOptions.DOCS_AND_FREQS;
-import static org.apache.lucene.index.IndexOptions.DOCS_AND_FREQS_AND_POSITIONS_AND_OFFSETS;
-
 import java.io.IOException;
 import java.lang.invoke.MethodHandles;
 import java.util.ArrayList;
@@ -83,6 +79,10 @@ import org.apache.solr.update.SolrIndexWriter;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import static org.apache.lucene.index.IndexOptions.DOCS;
+import static org.apache.lucene.index.IndexOptions.DOCS_AND_FREQS;
+import static org.apache.lucene.index.IndexOptions.DOCS_AND_FREQS_AND_POSITIONS_AND_OFFSETS;
+
 /**
  * This handler exposes the internal lucene index.  It is inspired by and 
  * modeled on Luke, the Lucene Index Browser by Andrzej Bialecki.
@@ -366,7 +366,7 @@ public class LukeRequestHandler extends RequestHandlerBase
       if (sfield != null && schema.isDynamicField(sfield.getName()) && schema.getDynamicPattern(sfield.getName()) != null) {
         fieldMap.add("dynamicBase", schema.getDynamicPattern(sfield.getName()));
       }
-      Terms terms = reader.fields().terms(fieldName);
+      Terms terms = reader.terms(fieldName);
       if (terms == null) { // Not indexed, so we need to report what we can (it made it through the fl param if specified)
         finfo.add( fieldName, fieldMap );
         continue;

solr/core/src/java/org/apache/solr/handler/component/QueryElevationComponent.java

@@ -38,7 +38,6 @@ import com.carrotsearch.hppc.IntIntHashMap;
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
-import org.apache.lucene.index.Fields;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.LeafReaderContext;
@@ -665,9 +664,7 @@ public class QueryElevationComponent extends SearchComponent implements SolrCore
       protected void doSetNextReader(LeafReaderContext context) throws IOException {
         //convert the ids to Lucene doc ids, the ordSet and termValues needs to be the same size as the number of elevation docs we have
         ordSet.clear();
-        Fields fields = context.reader().fields();
+        Terms terms = context.reader().terms(idField);
-        if (fields == null) return;
-        Terms terms = fields.terms(idField);
         if (terms == null) return;
         TermsEnum termsEnum = terms.iterator();
         BytesRefBuilder term = new BytesRefBuilder();

solr/core/src/java/org/apache/solr/handler/component/TermsComponent.java

@@ -15,22 +15,6 @@
  * limitations under the License.
  */
 package org.apache.solr.handler.component;
-import org.apache.lucene.index.*;
-import org.apache.lucene.util.BytesRef;
-import org.apache.lucene.util.BytesRefBuilder;
-import org.apache.lucene.util.CharsRefBuilder;
-import org.apache.lucene.util.StringHelper;
-import org.apache.solr.common.SolrException;
-import org.apache.solr.common.params.*;
-import org.apache.solr.common.util.NamedList;
-import org.apache.solr.common.util.SimpleOrderedMap;
-import org.apache.solr.common.util.StrUtils;
-import org.apache.solr.schema.FieldType;
-import org.apache.solr.schema.StrField;
-import org.apache.solr.request.SimpleFacets.CountPair;
-import org.apache.solr.search.SolrIndexSearcher;
-import org.apache.solr.util.BoundedTreeSet;
-import org.apache.solr.client.solrj.response.TermsResponse;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -39,6 +23,32 @@ import java.util.List;
 import java.util.Locale;
 import java.util.regex.Pattern;
 
+import org.apache.lucene.index.IndexReaderContext;
+import org.apache.lucene.index.LeafReader;
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.index.TermContext;
+import org.apache.lucene.index.Terms;
+import org.apache.lucene.index.TermsEnum;
+import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.BytesRefBuilder;
+import org.apache.lucene.util.CharsRefBuilder;
+import org.apache.lucene.util.StringHelper;
+import org.apache.solr.client.solrj.response.TermsResponse;
+import org.apache.solr.common.SolrException;
+import org.apache.solr.common.params.ModifiableSolrParams;
+import org.apache.solr.common.params.ShardParams;
+import org.apache.solr.common.params.SolrParams;
+import org.apache.solr.common.params.TermsParams;
+import org.apache.solr.common.util.NamedList;
+import org.apache.solr.common.util.SimpleOrderedMap;
+import org.apache.solr.common.util.StrUtils;
+import org.apache.solr.request.SimpleFacets.CountPair;
+import org.apache.solr.schema.FieldType;
+import org.apache.solr.schema.StrField;
+import org.apache.solr.search.SolrIndexSearcher;
+import org.apache.solr.util.BoundedTreeSet;
+
 /**
  * Return TermEnum information, useful for things like auto suggest.
  *
@@ -138,13 +148,12 @@ public class TermsComponent extends SearchComponent {
 
 
     final LeafReader indexReader = rb.req.getSearcher().getSlowAtomicReader();
-    Fields lfields = indexReader.fields();
 
     for (String field : fields) {
       NamedList<Integer> fieldTerms = new NamedList<>();
       termsResult.add(field, fieldTerms);
 
-      Terms terms = lfields.terms(field);
+      Terms terms = indexReader.terms(field);
       if (terms == null) {
         // field does not exist
         continue;
@@ -562,10 +571,9 @@ public class TermsComponent extends SearchComponent {
       Term[] queryTerms) throws IOException {
     TermsEnum termsEnum = null;
     for (LeafReaderContext context : topReaderContext.leaves()) {
-      final Fields fields = context.reader().fields();
       for (int i = 0; i < queryTerms.length; i++) {
         Term term = queryTerms[i];
-        final Terms terms = fields.terms(term.field());
+        final Terms terms = context.reader().terms(term.field());
         if (terms == null) {
           // field does not exist
           continue;

solr/core/src/java/org/apache/solr/highlight/DefaultSolrHighlighter.java

@@ -245,7 +245,7 @@ public class DefaultSolrHighlighter extends SolrHighlighter implements PluginInf
     try {
       // It'd be nice to know if payloads are on the tokenStream but the presence of the attribute isn't a good
       // indicator.
-      final Terms terms = request.getSearcher().getSlowAtomicReader().fields().terms(fieldName);
+      final Terms terms = request.getSearcher().getSlowAtomicReader().terms(fieldName);
       if (terms != null) {
         defaultPayloads = terms.hasPayloads();
       }

solr/core/src/java/org/apache/solr/request/SimpleFacets.java

@@ -37,7 +37,6 @@ import java.util.concurrent.SynchronousQueue;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Predicate;
 
-import org.apache.lucene.index.Fields;
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.MultiPostingsEnum;
@@ -935,8 +934,7 @@ public class SimpleFacets {
       prefixTermBytes = new BytesRef(indexedPrefix);
     }
 
-    Fields fields = r.fields();
+    Terms terms = r.terms(field);
-    Terms terms = fields==null ? null : fields.terms(field);
     TermsEnum termsEnum = null;
     SolrIndexSearcher.DocsEnumState deState = null;
     BytesRef term = null;

solr/core/src/java/org/apache/solr/search/DocSetUtil.java

@@ -21,7 +21,6 @@ import java.util.Iterator;
 import java.util.List;
 
 import org.apache.lucene.index.DirectoryReader;
-import org.apache.lucene.index.Fields;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.LeafReaderContext;
@@ -169,8 +168,7 @@ public class DocSetUtil {
     for (LeafReaderContext ctx : leaves) {
       assert leaves.get(ctx.ord) == ctx;
       LeafReader r = ctx.reader();
-      Fields f = r.fields();
+      Terms t = r.terms(field);
-      Terms t = f.terms(field);
       if (t == null) continue;  // field is missing
       TermsEnum te = t.iterator();
       if (te.seekExact(termVal)) {

solr/core/src/java/org/apache/solr/search/Filter.java

@@ -69,7 +69,7 @@ public abstract class Filter extends Query {
    *         represent the whole underlying index i.e. if the index has more than
    *         one segment the given reader only represents a single segment.
    *         The provided context is always an atomic context, so you can call
-   *         {@link org.apache.lucene.index.LeafReader#fields()}
+   *         {@link org.apache.lucene.index.LeafReader#terms(String)}
    *         on the context's reader, for example.
    *
    * @param acceptDocs

solr/core/src/java/org/apache/solr/search/FloatPayloadValueSource.java

@@ -20,7 +20,6 @@ package org.apache.solr.search;
 import java.io.IOException;
 import java.util.Map;
 
-import org.apache.lucene.index.Fields;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.PostingsEnum;
 import org.apache.lucene.index.Terms;
@@ -56,8 +55,7 @@ public class FloatPayloadValueSource extends ValueSource {
   @Override
   public FunctionValues getValues(Map context, LeafReaderContext readerContext) throws IOException {
 
-    Fields fields = readerContext.reader().fields();
+    final Terms terms = readerContext.reader().terms(indexedField);
-    final Terms terms = fields.terms(indexedField);
 
     FunctionValues defaultValues = defaultValueSource.getValues(context, readerContext);
 

solr/core/src/java/org/apache/solr/search/GraphTermsQParserPlugin.java

@@ -18,15 +18,19 @@
 
 package org.apache.solr.search;
 
-import org.apache.lucene.index.Fields;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.PostingsEnum;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.index.TermContext;
-import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermState;
+import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermsEnum;
 import org.apache.lucene.search.BulkScorer;
 import org.apache.lucene.search.ConstantScoreQuery;
@@ -49,11 +53,6 @@ import org.apache.solr.common.params.SolrParams;
 import org.apache.solr.request.SolrQueryRequest;
 import org.apache.solr.schema.FieldType;
 
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Set;
-
 /**
  *  The GraphTermsQuery builds a disjunction query from a list of terms. The terms are first filtered by the maxDocFreq parameter.
  *  This allows graph traversals to skip traversing high frequency nodes which is often desirable from a performance standpoint.
@@ -220,8 +219,7 @@ public class GraphTermsQParserPlugin extends QParserPlugin {
 
         private WeightOrDocIdSet rewrite(LeafReaderContext context) throws IOException {
           final LeafReader reader = context.reader();
-          final Fields fields = reader.fields();
+          Terms terms = reader.terms(field);
-          Terms terms = fields.terms(field);
           if(terms == null) {
             return new WeightOrDocIdSet(new BitDocIdSet(new FixedBitSet(reader.maxDoc()), 0));
           }

solr/core/src/java/org/apache/solr/search/JoinQParserPlugin.java

@@ -23,8 +23,8 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.Objects;
 
-import org.apache.lucene.index.Fields;
 import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.MultiPostingsEnum;
 import org.apache.lucene.index.PostingsEnum;
@@ -316,11 +316,11 @@ class JoinQuery extends Query {
         fastForRandomSet = new HashDocSet(sset.getDocs(), 0, sset.size());
       }
 
-      Fields fromFields = fromSearcher.getSlowAtomicReader().fields();
+
-      Fields toFields = fromSearcher==toSearcher ? fromFields : toSearcher.getSlowAtomicReader().fields();
+      LeafReader fromReader = fromSearcher.getSlowAtomicReader();
-      if (fromFields == null) return DocSet.EMPTY;
+      LeafReader toReader = fromSearcher==toSearcher ? fromReader : toSearcher.getSlowAtomicReader();
-      Terms terms = fromFields.terms(fromField);
+      Terms terms = fromReader.terms(fromField);
-      Terms toTerms = toFields.terms(toField);
+      Terms toTerms = toReader.terms(toField);
       if (terms == null || toTerms==null) return DocSet.EMPTY;
       String prefixStr = TrieField.getMainValuePrefix(fromSearcher.getSchema().getFieldType(fromField));
       BytesRef prefix = prefixStr == null ? null : new BytesRef(prefixStr);

solr/core/src/java/org/apache/solr/search/facet/FacetFieldProcessorByEnumTermsStream.java

@@ -22,7 +22,6 @@ import java.io.IOException;
 import java.util.Iterator;
 import java.util.List;
 
-import org.apache.lucene.index.Fields;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.MultiPostingsEnum;
 import org.apache.lucene.index.PostingsEnum;
@@ -156,8 +155,7 @@ class FacetFieldProcessorByEnumTermsStream extends FacetFieldProcessor implement
       }
     }
 
-    Fields fields = fcontext.searcher.getSlowAtomicReader().fields();
+    Terms terms = fcontext.searcher.getSlowAtomicReader().terms(sf.getName());
-    Terms terms = fields == null ? null : fields.terms(sf.getName());
 
     termsEnum = null;
     deState = null;

solr/core/src/java/org/apache/solr/uninverting/DocTermOrds.java

@@ -22,7 +22,7 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 
-import org.apache.lucene.codecs.PostingsFormat; // javadocs
+import org.apache.lucene.codecs.PostingsFormat;
 import org.apache.lucene.index.DocValues;
 import org.apache.lucene.index.DocValuesType;
 import org.apache.lucene.index.FieldInfo;
@@ -595,7 +595,7 @@ public class DocTermOrds implements Accountable {
     public OrdWrappedTermsEnum(LeafReader reader) throws IOException {
       assert indexedTermsArray != null;
       assert 0 != indexedTermsArray.length;
-      termsEnum = reader.fields().terms(field).iterator();
+      termsEnum = reader.terms(field).iterator();
     }
 
     @Override    

solr/core/src/java/org/apache/solr/update/SolrIndexSplitter.java

@@ -22,7 +22,6 @@ import java.util.ArrayList;
 import java.util.List;
 
 import org.apache.lucene.index.CodecReader;
-import org.apache.lucene.index.Fields;
 import org.apache.lucene.index.FilterCodecReader;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.LeafReader;
@@ -165,8 +164,7 @@ public class SolrIndexSplitter {
     }
     Bits liveDocs = reader.getLiveDocs();
 
-    Fields fields = reader.fields();
+    Terms terms = reader.terms(field.getName());
-    Terms terms = fields==null ? null : fields.terms(field.getName());
     TermsEnum termsEnum = terms==null ? null : terms.iterator();
     if (termsEnum == null) return docSets;