001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018package org.apache.hadoop.hbase; 019 020import java.io.IOException; 021import java.util.Map; 022import org.apache.hadoop.hbase.client.TableDescriptor; 023import org.apache.yetus.audience.InterfaceAudience; 024 025/** 026 * Get, remove and modify table descriptors. 027 */ 028@InterfaceAudience.Private 029public interface TableDescriptors { 030 031 /** 032 * Test whether a given table exists, i.e, has a table descriptor. 033 */ 034 default boolean exists(TableName tableName) throws IOException { 035 return get(tableName) != null; 036 } 037 038 /** Returns TableDescriptor for tablename */ 039 TableDescriptor get(TableName tableName) throws IOException; 040 041 /** 042 * Get Map of all NamespaceDescriptors for a given namespace. 043 * @return Map of all descriptors. 044 */ 045 Map<String, TableDescriptor> getByNamespace(String name) throws IOException; 046 047 /** 048 * Get Map of all TableDescriptors. Populates the descriptor cache as a side effect. 049 * </p> 050 * Notice: the key of map is the table name which contains namespace. It was generated by 051 * {@link TableName#getNameWithNamespaceInclAsString()}. 052 * @return Map of all descriptors. 053 */ 054 Map<String, TableDescriptor> getAll() throws IOException; 055 056 /** 057 * Add or update descriptor. Just call {@link #update(TableDescriptor, boolean)} with 058 * {@code cacheOnly} as {@code false}. 059 */ 060 default void update(TableDescriptor htd) throws IOException { 061 update(htd, false); 062 } 063 064 /** 065 * Add or update descriptor 066 * @param htd Descriptor to set into TableDescriptors 067 * @param cacheOnly only add the given {@code htd} to cache, without updating the storage. For 068 * example, when creating table, we will write the descriptor to fs when creating 069 * the fs layout, so we do not need to update the fs again. 070 */ 071 void update(TableDescriptor htd, boolean cacheOnly) throws IOException; 072 073 /** Returns Instance of table descriptor or null if none found. */ 074 TableDescriptor remove(TableName tablename) throws IOException; 075}