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1   /**
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  package org.apache.hadoop.hbase;
19  
20  import java.io.IOException;
21  import java.util.Map;
22  
23  import org.apache.hadoop.classification.InterfaceAudience;
24  import org.apache.hadoop.classification.InterfaceStability;
25  
26  /**
27   * Get, remove and modify table descriptors.
28   * Used by servers to host descriptors.
29   */
30  @InterfaceAudience.Private
31  public interface TableDescriptors {
32    /**
33     * @param tableName
34     * @return HTableDescriptor for tablename
35     * @throws IOException
36     */
37    HTableDescriptor get(final TableName tableName)
38    throws IOException;
39  
40    /**
41     * Get Map of all NamespaceDescriptors for a given namespace.
42     * @return Map of all descriptors.
43     * @throws IOException
44     */
45    Map<String, HTableDescriptor> getByNamespace(String name)
46    throws IOException;
47  
48    /**
49     * Get Map of all HTableDescriptors. Populates the descriptor cache as a
50     * side effect.
51     * @return Map of all descriptors.
52     * @throws IOException
53     */
54    Map<String, HTableDescriptor> getAll()
55    throws IOException;
56  
57    /**
58     * Add or update descriptor
59     * @param htd Descriptor to set into TableDescriptors
60     * @throws IOException
61     */
62    void add(final HTableDescriptor htd)
63    throws IOException;
64  
65    /**
66     * @param tablename
67     * @return Instance of table descriptor or null if none found.
68     * @throws IOException
69     */
70    HTableDescriptor remove(final TableName tablename)
71    throws IOException;
72  }