| /** |
| * 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.apex.malhar.lib.appdata.query; |
| |
| /** |
| * This is an interface for a Query Executor which is responsible for converting a query into a result |
| * that can be used by the user. |
| * @param <QUERY_TYPE> The type of the query to execute. |
| * @param <META_QUERY> The type of any additional meta data associated with the query when it was enqueued. |
| * @param <QUEUE_CONTEXT> The type of the queue context of the query. |
| * @param <RESULT> The type of the query's result. |
| * @since 3.0.0 |
| */ |
| public interface QueryExecutor<QUERY_TYPE, META_QUERY, QUEUE_CONTEXT, RESULT> |
| { |
| /** |
| * This method executes a query to produce a result. |
| * @param query The query to execute. |
| * @param metaQuery Any additional meta data associated with the query. |
| * @param queueContext Additoinal information required to queue the query properly. |
| * @return The result of the query if it's available. False otherwise. |
| */ |
| public RESULT executeQuery(QUERY_TYPE query, META_QUERY metaQuery, QUEUE_CONTEXT queueContext); |
| } |