View Javadoc

1   /**
2    * Copyright 2007 The Apache Software Foundation
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *     http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing, software
15   * distributed under the License is distributed on an "AS IS" BASIS,
16   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17   * See the License for the specific language governing permissions and
18   * limitations under the License.
19   */
20  package org.apache.hadoop.hbase;
21  
22  import java.util.Map.Entry;
23  
24  import org.apache.commons.logging.Log;
25  import org.apache.commons.logging.LogFactory;
26  import org.apache.hadoop.conf.Configuration;
27  import org.apache.hadoop.hbase.util.VersionInfo;
28  
29  /**
30   * Adds HBase configuration files to a Configuration
31   */
32  public class HBaseConfiguration extends Configuration {
33  
34    private static final Log LOG = LogFactory.getLog(HBaseConfiguration.class);
35  
36    /**
37     * Instantinating HBaseConfiguration() is deprecated. Please use
38     * HBaseConfiguration#create() to construct a plain Configuration
39     */
40    @Deprecated
41    public HBaseConfiguration() {
42      //TODO:replace with private constructor, HBaseConfiguration should not extend Configuration
43      super();
44      addHbaseResources(this);
45      LOG.warn("instantiating HBaseConfiguration() is deprecated. Please use" +
46      		" HBaseConfiguration#create() to construct a plain Configuration");
47    }
48  
49    /**
50     * Instantiating HBaseConfiguration() is deprecated. Please use
51     * HBaseConfiguration#create(conf) to construct a plain Configuration
52     */
53    @Deprecated
54    public HBaseConfiguration(final Configuration c) {
55      //TODO:replace with private constructor
56      this();
57      for (Entry<String, String>e: c) {
58        set(e.getKey(), e.getValue());
59      }
60    }
61  
62    private static void checkDefaultsVersion(Configuration conf) {
63      String defaultsVersion = conf.get("hbase.defaults.for.version");
64      String thisVersion = VersionInfo.getVersion();
65      if (!thisVersion.equals(defaultsVersion)) {
66        throw new RuntimeException(
67          "hbase-default.xml file seems to be for and old version of HBase (" +
68          defaultsVersion + "), this version is " + thisVersion);
69      }
70    }
71  
72    public static Configuration addHbaseResources(Configuration conf) {
73      conf.addResource("hbase-default.xml");
74      conf.addResource("hbase-site.xml");
75  
76      checkDefaultsVersion(conf);
77      return conf;
78    }
79  
80    /**
81     * Creates a Configuration with HBase resources
82     * @return a Configuration with HBase resources
83     */
84    public static Configuration create() {
85      Configuration conf = new Configuration();
86      return addHbaseResources(conf);
87    }
88  
89    /**
90     * Creates a clone of passed configuration.
91     * @param that Configuration to clone.
92     * @return a Configuration created with the hbase-*.xml files plus
93     * the given configuration.
94     */
95    public static Configuration create(final Configuration that) {
96      Configuration conf = create();
97      for (Entry<String, String>e: that) {
98        conf.set(e.getKey(), e.getValue());
99      }
100     return conf;
101   }
102 }