/** * 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. */package org.apache.hadoop.contrib.dlucene;import java.io.IOException;import org.apache.lucene.document.Document;import org.apache.lucene.index.Term;public interface IIndexUpdater {  /**   * Add a document to an index.   *    * @param doc the document   * @return the shard name   * @throws IOException   */  public void addDocument(Document doc) throws IOException;  /**   * Remove documents from an index.   *    * @param term the search term   * @return the number of documents removed   * @throws IOException   */  public int removeDocuments(Term term) throws IOException;  /**   * Commit changes to an index.   *    * @throws IOException   */  public void commit() throws IOException;}