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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.hbase.classification.InterfaceAudience;
24  
25  /**
26   * Get, remove and modify table descriptors.
27   * Used by servers to host descriptors.
28   */
29  @InterfaceAudience.Private
30  public interface TableDescriptors {
31    /**
32     * @param tableName
33     * @return TableDescriptor for tablename
34     * @throws IOException
35     */
36    HTableDescriptor get(final TableName tableName)
37        throws IOException;
38  
39    /**
40     * Get Map of all NamespaceDescriptors for a given namespace.
41     * @return Map of all descriptors.
42     * @throws IOException
43     */
44    Map<String, HTableDescriptor> getByNamespace(String name)
45    throws IOException;
46  
47    /**
48     * Get Map of all HTableDescriptors. Populates the descriptor cache as a
49     * side effect.
50     * @return Map of all descriptors.
51     * @throws IOException
52     */
53    Map<String, HTableDescriptor> getAll()
54    throws IOException;
55
56    /**
57     * Get Map of all TableDescriptors. Populates the descriptor cache as a
58     * side effect.
59     * @return Map of all descriptors.
60     * @throws IOException
61     */
62    Map<String, HTableDescriptor> getAllDescriptors()
63        throws IOException;
64
65    /**
66     * Add or update descriptor
67     * @param htd Descriptor to set into TableDescriptors
68     * @throws IOException
69     */
70    void add(final HTableDescriptor htd)
71    throws IOException;
72  
73    /**
74     * @param tablename
75     * @return Instance of table descriptor or null if none found.
76     * @throws IOException
77     */
78    HTableDescriptor remove(final TableName tablename)
79    throws IOException;
80  
81    /**
82     * Enables the tabledescriptor cache
83     */
84    void setCacheOn() throws IOException;
85
86    /**
87     * Disables the tabledescriptor cache
88     */
89    void setCacheOff() throws IOException;
90  }