--- /dev/null
+package org.apache.lucene.search;
+
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.io.IOException;
+
+import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.index.Term;
+
+/**
+ * Subclass of FilteredTermEnum for enumerating a single term.
+ * <p>
+ * This can be used by {@link MultiTermQuery}s that need only visit one term,
+ * but want to preserve MultiTermQuery semantics such as
+ * {@link MultiTermQuery#rewriteMethod}.
+ */
+public class SingleTermEnum extends FilteredTermEnum {
+ private Term singleTerm;
+ private boolean endEnum = false;
+
+ /**
+ * Creates a new <code>SingleTermEnum</code>.
+ * <p>
+ * After calling the constructor the enumeration is already pointing to the term,
+ * if it exists.
+ */
+ public SingleTermEnum(IndexReader reader, Term singleTerm) throws IOException {
+ super();
+ this.singleTerm = singleTerm;
+ setEnum(reader.terms(singleTerm));
+ }
+
+ @Override
+ public float difference() {
+ return 1.0F;
+ }
+
+ @Override
+ protected boolean endEnum() {
+ return endEnum;
+ }
+
+ @Override
+ protected boolean termCompare(Term term) {
+ if (term.equals(singleTerm)) {
+ return true;
+ } else {
+ endEnum = true;
+ return false;
+ }
+ }
+}