| /** |
| * 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.hdfs.server.federation.store; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| import org.apache.hadoop.hdfs.server.federation.store.records.BaseRecord; |
| import org.apache.hadoop.hdfs.server.federation.store.records.Query; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * Set of utility functions used to work with the State Store. |
| */ |
| public final class StateStoreUtils { |
| |
| private static final Logger LOG = |
| LoggerFactory.getLogger(StateStoreUtils.class); |
| |
| |
| private StateStoreUtils() { |
| // Utility class |
| } |
| |
| /** |
| * Get the base class for a record class. If we get an implementation of a |
| * record we will return the real parent record class. |
| * |
| * @param clazz Class of the data record to check. |
| * @return Base class for the record. |
| */ |
| @SuppressWarnings("unchecked") |
| public static <T extends BaseRecord> |
| Class<? extends BaseRecord> getRecordClass(final Class<T> clazz) { |
| |
| // We ignore the Impl classes and go to the super class |
| Class<? extends BaseRecord> actualClazz = clazz; |
| while (actualClazz.getSimpleName().endsWith("Impl")) { |
| actualClazz = (Class<? extends BaseRecord>) actualClazz.getSuperclass(); |
| } |
| |
| // Check if we went too far |
| if (actualClazz.equals(BaseRecord.class)) { |
| LOG.error("We went too far ({}) with {}", actualClazz, clazz); |
| actualClazz = clazz; |
| } |
| return actualClazz; |
| } |
| |
| /** |
| * Get the base class for a record. If we get an implementation of a record we |
| * will return the real parent record class. |
| * |
| * @param record Record to check its main class. |
| * @return Base class for the record. |
| */ |
| public static <T extends BaseRecord> |
| Class<? extends BaseRecord> getRecordClass(final T record) { |
| return getRecordClass(record.getClass()); |
| } |
| |
| /** |
| * Get the base class name for a record. If we get an implementation of a |
| * record we will return the real parent record class. |
| * |
| * @param clazz Class of the data record to check. |
| * @return Name of the base class for the record. |
| */ |
| public static <T extends BaseRecord> String getRecordName( |
| final Class<T> clazz) { |
| return getRecordClass(clazz).getSimpleName(); |
| } |
| |
| /** |
| * Filters a list of records to find all records matching the query. |
| * |
| * @param query Map of field names and objects to use to filter results. |
| * @param records List of data records to filter. |
| * @return List of all records matching the query (or empty list if none |
| * match), null if the data set could not be filtered. |
| */ |
| public static <T extends BaseRecord> List<T> filterMultiple( |
| final Query<T> query, final Iterable<T> records) { |
| |
| List<T> matchingList = new ArrayList<>(); |
| for (T record : records) { |
| if (query.matches(record)) { |
| matchingList.add(record); |
| } |
| } |
| return matchingList; |
| } |
| } |