--- /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;
+
+abstract class TermCollectingRewrite<Q extends Query> extends MultiTermQuery.RewriteMethod {
+
+ /** Return a suitable top-level Query for holding all expanded terms. */
+ protected abstract Q getTopLevelQuery() throws IOException;
+
+ /** Add a MultiTermQuery term to the top-level query */
+ protected abstract void addClause(Q topLevel, Term term, float boost) throws IOException;
+
+ protected final void collectTerms(IndexReader reader, MultiTermQuery query, TermCollector collector) throws IOException {
+ final FilteredTermEnum enumerator = query.getEnum(reader);
+ try {
+ do {
+ final Term t = enumerator.term();
+ if (t == null || !collector.collect(t, enumerator.difference()))
+ break;
+ } while (enumerator.next());
+ } finally {
+ enumerator.close();
+ }
+ }
+
+ protected interface TermCollector {
+ /** return false to stop collecting */
+ boolean collect(Term t, float boost) throws IOException;
+ }
+}