| /* |
| * 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.solr.search; |
| |
| import org.apache.lucene.search.IndexSearcher; |
| |
| /** The PostFilter interface provides a mechanism to further filter documents |
| * after they have already gone through the main query and other filters. |
| * This is appropriate for filters with a very high cost. |
| * <p> |
| * The filtering mechanism used is a {@link DelegatingCollector} |
| * that allows the filter to not call the delegate for certain documents, |
| * thus effectively filtering them out. This also avoids the normal |
| * filter advancing mechanism which asks for the first acceptable document on |
| * or after the target (which is undesirable for expensive filters). |
| * This collector interface also enables better performance when an external system |
| * must be consulted, since document ids may be buffered and batched into |
| * a single request to the external system. |
| * <p> |
| * Implementations of this interface must also be a Query. |
| * If an implementation can only support the collector method of |
| * filtering through getFilterCollector, then ExtendedQuery.getCached() |
| * should always return false, and ExtendedQuery.getCost() should |
| * return no less than 100. |
| * |
| * @see ExtendedQueryBase |
| */ |
| public interface PostFilter extends ExtendedQuery { |
| |
| /** Returns a DelegatingCollector to be run after the main query and all of its filters, but before any sorting or grouping collectors */ |
| public DelegatingCollector getFilterCollector(IndexSearcher searcher); |
| } |