LUCENE-3312: inline Iterator and don't clone into ArrayList.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene3312@1377263 13f79535-47bb-0310-9956-ffa450edef68

lucene/core/src/java/org/apache/lucene/document/Document.java

@@ -46,8 +46,6 @@ public final class Document implements IndexDocument{
 
   private final List<Field> fields = new ArrayList<Field>();
 
-  //private final List<Field> fields
-
   /** Constructs a new document with no fields. */
   public Document() {}
   
@@ -291,28 +289,24 @@ public final class Document implements IndexDocument{
   /** Obtains all indexed fields in document */
   @Override
   public Iterable<? extends IndexableField> indexableFields() {
-    Iterator<Field> it = indexedFieldsIterator();
-    
-    List<IndexableField> result = new ArrayList<IndexableField>();
-    while(it.hasNext()) {
-      result.add(it.next());
+    return new Iterable<Field>() {
+      @Override
+      public Iterator<Field> iterator() {
+        return Document.this.indexedFieldsIterator();
       }
-    
-    return result;
+    };
   }
 
 
   /** Obtains all stored fields in document. */
   @Override
   public Iterable<? extends StorableField> storableFields() {
-    Iterator<Field> it = storedFieldsIterator();
-    
-    List<StorableField> result = new ArrayList<StorableField>();
-    while(it.hasNext()) {
-      result.add(it.next());
+    return new Iterable<Field>() {
+      @Override
+      public Iterator<Field> iterator() {
+        return Document.this.storedFieldsIterator();
       }
-    
-    return result;
+    };
   }
 
   private Iterator<Field> storedFieldsIterator() {