--- /dev/null
+package org.apache.lucene.index;
+
+/**
+ * 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;
+
+abstract class DocConsumerPerThread {
+
+ /** Process the document. If there is
+ * something for this document to be done in docID order,
+ * you should encapsulate that as a
+ * DocumentsWriter.DocWriter and return it.
+ * DocumentsWriter then calls finish() on this object
+ * when it's its turn. */
+ abstract DocumentsWriter.DocWriter processDocument() throws IOException;
+
+ abstract void abort();
+}