remove FieldsEnum and replace with Iterator<String>

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1372246 13f79535-47bb-0310-9956-ffa450edef68
andyfowler · Aug 13, 2012 · ac1d9eb · ac1d9eb
1 parent 2f85e11
commit ac1d9eb
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diff --git a/lucene/CHANGES.txt b/lucene/CHANGES.txt
@@ -27,6 +27,10 @@ API Changes
   otherwise returns the current payload. You can now call it multiple
   times per position if you want. (Robert Muir)
 
+* Removed FieldsEnum. Fields API instead implements Iterable<String>
+  and exposes Iterator, so you can iterate over field names with
+  for (String field : fields) instead.  (Robert Muir)
+
 Bug Fixes
 
 * LUCENE-4297: BooleanScorer2 would multiply the coord() factor

diff --git a/lucene/MIGRATE.txt b/lucene/MIGRATE.txt
@@ -9,7 +9,7 @@ enumeration APIs.  Here are the major changes:
     by the BytesRef class (which provides an offset + length "slice"
     into an existing byte[]).
 
-  * Fields are separately enumerated (FieldsEnum) from the terms
+  * Fields are separately enumerated (Fields.iterator()) from the terms
     within each field (TermEnum).  So instead of this:
 
         TermEnum termsEnum = ...;
@@ -20,10 +20,8 @@ enumeration APIs.  Here are the major changes:
 
     Do this:
 
-        FieldsEnum fieldsEnum = ...;
-        String field;
-        while((field = fieldsEnum.next()) != null) {
-            TermsEnum termsEnum = fieldsEnum.terms();
+        for(String field : fields) {
+            TermsEnum termsEnum = fields.terms(field);
             BytesRef text;
             while((text = termsEnum.next()) != null) {
               System.out.println("field=" + field + "; text=" + text.utf8ToString());

diff --git a/lucene/benchmark/src/test/org/apache/lucene/benchmark/byTask/TestPerfTasksLogic.java b/lucene/benchmark/src/test/org/apache/lucene/benchmark/byTask/TestPerfTasksLogic.java
@@ -43,7 +43,6 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.DocsEnum;
 import org.apache.lucene.index.Fields;
-import org.apache.lucene.index.FieldsEnum;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexWriterConfig.OpenMode;
@@ -493,13 +492,13 @@ public void testReadTokens() throws Exception {
 
     int totalTokenCount2 = 0;
 
-    FieldsEnum fields = MultiFields.getFields(reader).iterator();
-    String fieldName = null;
-    while((fieldName = fields.next()) != null) {
+    Fields fields = MultiFields.getFields(reader);
+
+    for (String fieldName : fields) {
       if (fieldName.equals(DocMaker.ID_FIELD) || fieldName.equals(DocMaker.DATE_MSEC_FIELD) || fieldName.equals(DocMaker.TIME_SEC_FIELD)) {
         continue;
       }
-      Terms terms = fields.terms();
+      Terms terms = fields.terms(fieldName);
       if (terms == null) {
         continue;
       }

diff --git a/lucene/core/src/java/org/apache/lucene/codecs/BlockTermsReader.java b/lucene/core/src/java/org/apache/lucene/codecs/BlockTermsReader.java
@@ -27,7 +27,6 @@
 import org.apache.lucene.index.FieldInfo.IndexOptions;
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.FieldInfos;
-import org.apache.lucene.index.FieldsEnum;
 import org.apache.lucene.index.IndexFileNames;
 import org.apache.lucene.index.TermState;
 import org.apache.lucene.index.Terms;
@@ -40,6 +39,7 @@
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.DoubleBarrelLRUCache;
+import org.apache.lucene.util.UnmodifiableIterator;
 
 /** Handles a terms dict, but decouples all details of
  *  doc/freqs/positions reading to an instance of {@link
@@ -184,8 +184,8 @@ public void close() throws IOException {
   }
 
   @Override
-  public FieldsEnum iterator() {
-    return new TermFieldsEnum();
+  public Iterator<String> iterator() {
+    return new UnmodifiableIterator<String>(fields.keySet().iterator());
   }
 
   @Override
@@ -199,32 +199,6 @@ public int size() {
     return fields.size();
   }
 
-  // Iterates through all fields
-  private class TermFieldsEnum extends FieldsEnum {
-    final Iterator<FieldReader> it;
-    FieldReader current;
-
-    TermFieldsEnum() {
-      it = fields.values().iterator();
-    }
-
-    @Override
-    public String next() {
-      if (it.hasNext()) {
-        current = it.next();
-        return current.fieldInfo.name;
-      } else {
-        current = null;
-        return null;
-      }
-    }
-
-    @Override
-    public Terms terms() throws IOException {
-      return current;
-    }
-  }
-
   private class FieldReader extends Terms {
     final long numTerms;
     final FieldInfo fieldInfo;

diff --git a/lucene/core/src/java/org/apache/lucene/codecs/BlockTreeTermsReader.java b/lucene/core/src/java/org/apache/lucene/codecs/BlockTreeTermsReader.java
@@ -31,7 +31,6 @@
 import org.apache.lucene.index.FieldInfo.IndexOptions;
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.FieldInfos;
-import org.apache.lucene.index.FieldsEnum;
 import org.apache.lucene.index.IndexFileNames;
 import org.apache.lucene.index.TermState;
 import org.apache.lucene.index.Terms;
@@ -46,6 +45,7 @@
 import org.apache.lucene.util.IOUtils;
 import org.apache.lucene.util.RamUsageEstimator;
 import org.apache.lucene.util.StringHelper;
+import org.apache.lucene.util.UnmodifiableIterator;
 import org.apache.lucene.util.automaton.CompiledAutomaton;
 import org.apache.lucene.util.automaton.RunAutomaton;
 import org.apache.lucene.util.automaton.Transition;
@@ -199,8 +199,8 @@ public void close() throws IOException {
   }
 
   @Override
-  public FieldsEnum iterator() {
-    return new TermFieldsEnum();
+  public Iterator<String> iterator() {
+    return new UnmodifiableIterator<String>(fields.keySet().iterator());
   }
 
   @Override
@@ -214,32 +214,6 @@ public int size() {
     return fields.size();
   }
 
-  // Iterates through all fields
-  private class TermFieldsEnum extends FieldsEnum {
-    final Iterator<FieldReader> it;
-    FieldReader current;
-
-    TermFieldsEnum() {
-      it = fields.values().iterator();
-    }
-
-    @Override
-    public String next() {
-      if (it.hasNext()) {
-        current = it.next();
-        return current.fieldInfo.name;
-      } else {
-        current = null;
-        return null;
-      }
-    }
-
-    @Override
-    public Terms terms() throws IOException {
-      return current;
-    }
-  }
-
   // for debugging
   String brToString(BytesRef b) {
     if (b == null) {

diff --git a/lucene/core/src/java/org/apache/lucene/codecs/FieldsConsumer.java b/lucene/core/src/java/org/apache/lucene/codecs/FieldsConsumer.java
@@ -22,7 +22,6 @@
 
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.Fields;
-import org.apache.lucene.index.FieldsEnum;
 import org.apache.lucene.index.MergeState;
 import org.apache.lucene.index.SegmentWriteState; // javadocs
 import org.apache.lucene.index.Terms;
@@ -53,13 +52,10 @@ public abstract class FieldsConsumer implements Closeable {
   public abstract void close() throws IOException;
 
   public void merge(MergeState mergeState, Fields fields) throws IOException {
-    FieldsEnum fieldsEnum = fields.iterator();
-    assert fieldsEnum != null;
-    String field;
-    while((field = fieldsEnum.next()) != null) {
+    for (String field : fields) {
       mergeState.fieldInfo = mergeState.fieldInfos.fieldInfo(field);
       assert mergeState.fieldInfo != null : "FieldInfo for field is null: "+ field;
-      Terms terms = fieldsEnum.terms();
+      Terms terms = fields.terms(field);
       if (terms != null) {
         final TermsConsumer termsConsumer = addField(mergeState.fieldInfo);
         termsConsumer.merge(mergeState, terms.iterator(null));

diff --git a/lucene/core/src/java/org/apache/lucene/codecs/TermVectorsWriter.java b/lucene/core/src/java/org/apache/lucene/codecs/TermVectorsWriter.java
@@ -26,7 +26,6 @@
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.FieldInfos;
 import org.apache.lucene.index.Fields;
-import org.apache.lucene.index.FieldsEnum;
 import org.apache.lucene.index.MergeState;
 import org.apache.lucene.index.PayloadProcessorProvider.PayloadProcessor;
 import org.apache.lucene.index.PayloadProcessorProvider.ReaderPayloadProcessor;
@@ -211,8 +210,6 @@ protected final void addAllDocVectors(Fields vectors, MergeState mergeState) thr
     }
     startDocument(numFields);
 
-    final FieldsEnum fieldsEnum = vectors.iterator();
-    String fieldName;
     String lastFieldName = null;
 
     TermsEnum termsEnum = null;
@@ -221,13 +218,13 @@ protected final void addAllDocVectors(Fields vectors, MergeState mergeState) thr
     final ReaderPayloadProcessor readerPayloadProcessor = mergeState.currentReaderPayloadProcessor;
     PayloadProcessor payloadProcessor = null;
 
-    while((fieldName = fieldsEnum.next()) != null) {
+    for(String fieldName : vectors) {
       final FieldInfo fieldInfo = mergeState.fieldInfos.fieldInfo(fieldName);
 
       assert lastFieldName == null || fieldName.compareTo(lastFieldName) > 0: "lastFieldName=" + lastFieldName + " fieldName=" + fieldName;
       lastFieldName = fieldName;
 
-      final Terms terms = fieldsEnum.terms();
+      final Terms terms = vectors.terms(fieldName);
       if (terms == null) {
         // FieldsEnum shouldn't lie...
         continue;

diff --git a/lucene/core/src/java/org/apache/lucene/codecs/bloom/BloomFilteringPostingsFormat.java b/lucene/core/src/java/org/apache/lucene/codecs/bloom/BloomFilteringPostingsFormat.java
@@ -21,6 +21,7 @@
 import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.HashMap;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -35,7 +36,6 @@
 import org.apache.lucene.index.DocsAndPositionsEnum;
 import org.apache.lucene.index.DocsEnum;
 import org.apache.lucene.index.FieldInfo;
-import org.apache.lucene.index.FieldsEnum;
 import org.apache.lucene.index.IndexFileNames;
 import org.apache.lucene.index.SegmentReadState;
 import org.apache.lucene.index.SegmentWriteState;
@@ -44,7 +44,6 @@
 import org.apache.lucene.store.DataOutput;
 import org.apache.lucene.store.IndexInput;
 import org.apache.lucene.store.IndexOutput;
-import org.apache.lucene.util.AttributeSource;
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.FuzzySet;
@@ -187,9 +186,8 @@ public BloomFilteredFieldsProducer(SegmentReadState state)
 
     }
 
-    public FieldsEnum iterator() throws IOException {
-      return new BloomFilteredFieldsEnum(delegateFieldsProducer.iterator(),
-          bloomsByFieldName);
+    public Iterator<String> iterator() {
+      return delegateFieldsProducer.iterator();
     }
 
     public void close() throws IOException {
@@ -217,44 +215,6 @@ public long getUniqueTermCount() throws IOException {
       return delegateFieldsProducer.getUniqueTermCount();
     }
 
-    // Not all fields in a segment may be subject to a bloom filter. This class
-    // wraps Terms objects appropriately if a filtering request is present
-    class BloomFilteredFieldsEnum extends FieldsEnum {
-      private FieldsEnum delegateFieldsEnum;
-      private HashMap<String,FuzzySet> bloomsByFieldName;
-      private String currentFieldName;
-
-      public BloomFilteredFieldsEnum(FieldsEnum iterator,
-          HashMap<String,FuzzySet> bloomsByFieldName) {
-        this.delegateFieldsEnum = iterator;
-        this.bloomsByFieldName = bloomsByFieldName;
-      }
-
-      public AttributeSource attributes() {
-        return delegateFieldsEnum.attributes();
-      }
-
-      public String next() throws IOException {
-        currentFieldName = delegateFieldsEnum.next();
-        return currentFieldName;
-      }
-
-      public Terms terms() throws IOException {
-        FuzzySet filter = bloomsByFieldName.get(currentFieldName);
-        if (filter == null) {
-          return delegateFieldsEnum.terms();
-        } else {
-          Terms result = delegateFieldsEnum.terms();
-          if (result == null) {
-            return null;
-          }
-          // wrap the terms object with a bloom filter
-          return new BloomFilteredTerms(result, filter);
-        }
-      }
-
-    }
-
     class BloomFilteredTerms extends Terms {
       private Terms delegateTerms;
       private FuzzySet filter;

diff --git a/lucene/core/src/java/org/apache/lucene/codecs/lucene3x/Lucene3xFields.java b/lucene/core/src/java/org/apache/lucene/codecs/lucene3x/Lucene3xFields.java
@@ -30,7 +30,6 @@
 import org.apache.lucene.index.FieldInfo.IndexOptions;
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.FieldInfos;
-import org.apache.lucene.index.FieldsEnum;
 import org.apache.lucene.index.IndexFileNames;
 import org.apache.lucene.index.SegmentInfo;
 import org.apache.lucene.index.Term;
@@ -42,6 +41,7 @@
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.UnicodeUtil;
+import org.apache.lucene.util.UnmodifiableIterator;
 
 /** Exposes flex API on a pre-flex index, as a codec. 
  * @lucene.experimental
@@ -133,8 +133,8 @@ protected boolean sortTermsByUnicode() {
   }
 
   @Override
-  public FieldsEnum iterator() throws IOException {
-    return new PreFlexFieldsEnum();
+  public Iterator<String> iterator() {
+    return new UnmodifiableIterator<String>(fields.keySet().iterator());
   }
 
   @Override
@@ -178,30 +178,6 @@ public void close() throws IOException {
       proxStream.close();
     }
   }
-
-  private class PreFlexFieldsEnum extends FieldsEnum {
-    final Iterator<FieldInfo> it;
-    FieldInfo current;
-
-    public PreFlexFieldsEnum() throws IOException {
-      it = fields.values().iterator();
-    }
-
-    @Override
-    public String next() {
-      if (it.hasNext()) {
-        current = it.next();
-        return current.name;
-      } else {
-        return null;
-      }
-    }
-
-    @Override
-    public Terms terms() throws IOException {
-      return Lucene3xFields.this.terms(current.name);
-    }
-  }
 
   private class PreTerms extends Terms {
     final FieldInfo fieldInfo;