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| <pre><span class="source-line-no">001</span><span id="line-1">/*</span> |
| <span class="source-line-no">002</span><span id="line-2"> * Licensed to the Apache Software Foundation (ASF) under one</span> |
| <span class="source-line-no">003</span><span id="line-3"> * or more contributor license agreements. See the NOTICE file</span> |
| <span class="source-line-no">004</span><span id="line-4"> * distributed with this work for additional information</span> |
| <span class="source-line-no">005</span><span id="line-5"> * regarding copyright ownership. The ASF licenses this file</span> |
| <span class="source-line-no">006</span><span id="line-6"> * to you under the Apache License, Version 2.0 (the</span> |
| <span class="source-line-no">007</span><span id="line-7"> * "License"); you may not use this file except in compliance</span> |
| <span class="source-line-no">008</span><span id="line-8"> * with the License. You may obtain a copy of the License at</span> |
| <span class="source-line-no">009</span><span id="line-9"> *</span> |
| <span class="source-line-no">010</span><span id="line-10"> * http://www.apache.org/licenses/LICENSE-2.0</span> |
| <span class="source-line-no">011</span><span id="line-11"> *</span> |
| <span class="source-line-no">012</span><span id="line-12"> * Unless required by applicable law or agreed to in writing, software</span> |
| <span class="source-line-no">013</span><span id="line-13"> * distributed under the License is distributed on an "AS IS" BASIS,</span> |
| <span class="source-line-no">014</span><span id="line-14"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span> |
| <span class="source-line-no">015</span><span id="line-15"> * See the License for the specific language governing permissions and</span> |
| <span class="source-line-no">016</span><span id="line-16"> * limitations under the License.</span> |
| <span class="source-line-no">017</span><span id="line-17"> */</span> |
| <span class="source-line-no">018</span><span id="line-18">package org.apache.hadoop.hbase.wal;</span> |
| <span class="source-line-no">019</span><span id="line-19"></span> |
| <span class="source-line-no">020</span><span id="line-20">import java.io.Closeable;</span> |
| <span class="source-line-no">021</span><span id="line-21">import java.io.IOException;</span> |
| <span class="source-line-no">022</span><span id="line-22">import java.util.concurrent.atomic.AtomicReference;</span> |
| <span class="source-line-no">023</span><span id="line-23">import org.apache.hadoop.conf.Configuration;</span> |
| <span class="source-line-no">024</span><span id="line-24">import org.apache.hadoop.hbase.Abortable;</span> |
| <span class="source-line-no">025</span><span id="line-25">import org.apache.hadoop.hbase.regionserver.wal.MetricsWAL;</span> |
| <span class="source-line-no">026</span><span id="line-26">import org.apache.hadoop.hbase.wal.WALFactory.Providers;</span> |
| <span class="source-line-no">027</span><span id="line-27">import org.apache.yetus.audience.InterfaceAudience;</span> |
| <span class="source-line-no">028</span><span id="line-28"></span> |
| <span class="source-line-no">029</span><span id="line-29">/**</span> |
| <span class="source-line-no">030</span><span id="line-30"> * A lazy initialized WAL provider for holding the WALProvider for some special tables, such as</span> |
| <span class="source-line-no">031</span><span id="line-31"> * hbase:meta, hbase:replication, etc.</span> |
| <span class="source-line-no">032</span><span id="line-32"> */</span> |
| <span class="source-line-no">033</span><span id="line-33">@InterfaceAudience.Private</span> |
| <span class="source-line-no">034</span><span id="line-34">class LazyInitializedWALProvider implements Closeable {</span> |
| <span class="source-line-no">035</span><span id="line-35"></span> |
| <span class="source-line-no">036</span><span id="line-36"> private final WALFactory factory;</span> |
| <span class="source-line-no">037</span><span id="line-37"></span> |
| <span class="source-line-no">038</span><span id="line-38"> private final String providerId;</span> |
| <span class="source-line-no">039</span><span id="line-39"></span> |
| <span class="source-line-no">040</span><span id="line-40"> private final String providerConfigName;</span> |
| <span class="source-line-no">041</span><span id="line-41"></span> |
| <span class="source-line-no">042</span><span id="line-42"> private final Abortable abortable;</span> |
| <span class="source-line-no">043</span><span id="line-43"></span> |
| <span class="source-line-no">044</span><span id="line-44"> private final AtomicReference<WALProvider> holder = new AtomicReference<>();</span> |
| <span class="source-line-no">045</span><span id="line-45"></span> |
| <span class="source-line-no">046</span><span id="line-46"> LazyInitializedWALProvider(WALFactory factory, String providerId, String providerConfigName,</span> |
| <span class="source-line-no">047</span><span id="line-47"> Abortable abortable) {</span> |
| <span class="source-line-no">048</span><span id="line-48"> this.factory = factory;</span> |
| <span class="source-line-no">049</span><span id="line-49"> this.providerId = providerId;</span> |
| <span class="source-line-no">050</span><span id="line-50"> this.providerConfigName = providerConfigName;</span> |
| <span class="source-line-no">051</span><span id="line-51"> this.abortable = abortable;</span> |
| <span class="source-line-no">052</span><span id="line-52"> }</span> |
| <span class="source-line-no">053</span><span id="line-53"></span> |
| <span class="source-line-no">054</span><span id="line-54"> WALProvider getProvider() throws IOException {</span> |
| <span class="source-line-no">055</span><span id="line-55"> Configuration conf = factory.getConf();</span> |
| <span class="source-line-no">056</span><span id="line-56"> for (;;) {</span> |
| <span class="source-line-no">057</span><span id="line-57"> WALProvider provider = this.holder.get();</span> |
| <span class="source-line-no">058</span><span id="line-58"> if (provider != null) {</span> |
| <span class="source-line-no">059</span><span id="line-59"> return provider;</span> |
| <span class="source-line-no">060</span><span id="line-60"> }</span> |
| <span class="source-line-no">061</span><span id="line-61"> Class<? extends WALProvider> clz = null;</span> |
| <span class="source-line-no">062</span><span id="line-62"> if (conf.get(providerConfigName) == null) {</span> |
| <span class="source-line-no">063</span><span id="line-63"> try {</span> |
| <span class="source-line-no">064</span><span id="line-64"> clz = conf.getClass(WALFactory.WAL_PROVIDER, Providers.defaultProvider.clazz,</span> |
| <span class="source-line-no">065</span><span id="line-65"> WALProvider.class);</span> |
| <span class="source-line-no">066</span><span id="line-66"> } catch (Throwable t) {</span> |
| <span class="source-line-no">067</span><span id="line-67"> // the WAL provider should be an enum. Proceed</span> |
| <span class="source-line-no">068</span><span id="line-68"> }</span> |
| <span class="source-line-no">069</span><span id="line-69"> }</span> |
| <span class="source-line-no">070</span><span id="line-70"> if (clz == null) {</span> |
| <span class="source-line-no">071</span><span id="line-71"> clz = factory.getProviderClass(providerConfigName,</span> |
| <span class="source-line-no">072</span><span id="line-72"> conf.get(WALFactory.WAL_PROVIDER, WALFactory.DEFAULT_WAL_PROVIDER));</span> |
| <span class="source-line-no">073</span><span id="line-73"> }</span> |
| <span class="source-line-no">074</span><span id="line-74"> provider = WALFactory.createProvider(clz);</span> |
| <span class="source-line-no">075</span><span id="line-75"> provider.init(factory, conf, providerId, this.abortable);</span> |
| <span class="source-line-no">076</span><span id="line-76"> provider.addWALActionsListener(new MetricsWAL());</span> |
| <span class="source-line-no">077</span><span id="line-77"> if (this.holder.compareAndSet(null, provider)) {</span> |
| <span class="source-line-no">078</span><span id="line-78"> return provider;</span> |
| <span class="source-line-no">079</span><span id="line-79"> } else {</span> |
| <span class="source-line-no">080</span><span id="line-80"> // someone is ahead of us, close and try again.</span> |
| <span class="source-line-no">081</span><span id="line-81"> provider.close();</span> |
| <span class="source-line-no">082</span><span id="line-82"> }</span> |
| <span class="source-line-no">083</span><span id="line-83"> }</span> |
| <span class="source-line-no">084</span><span id="line-84"> }</span> |
| <span class="source-line-no">085</span><span id="line-85"></span> |
| <span class="source-line-no">086</span><span id="line-86"> /**</span> |
| <span class="source-line-no">087</span><span id="line-87"> * Get the provider if it already initialized, otherwise just return {@code null} instead of</span> |
| <span class="source-line-no">088</span><span id="line-88"> * creating it.</span> |
| <span class="source-line-no">089</span><span id="line-89"> */</span> |
| <span class="source-line-no">090</span><span id="line-90"> WALProvider getProviderNoCreate() {</span> |
| <span class="source-line-no">091</span><span id="line-91"> return holder.get();</span> |
| <span class="source-line-no">092</span><span id="line-92"> }</span> |
| <span class="source-line-no">093</span><span id="line-93"></span> |
| <span class="source-line-no">094</span><span id="line-94"> @Override</span> |
| <span class="source-line-no">095</span><span id="line-95"> public void close() throws IOException {</span> |
| <span class="source-line-no">096</span><span id="line-96"> WALProvider provider = this.holder.get();</span> |
| <span class="source-line-no">097</span><span id="line-97"> if (provider != null) {</span> |
| <span class="source-line-no">098</span><span id="line-98"> provider.close();</span> |
| <span class="source-line-no">099</span><span id="line-99"> }</span> |
| <span class="source-line-no">100</span><span id="line-100"> }</span> |
| <span class="source-line-no">101</span><span id="line-101"></span> |
| <span class="source-line-no">102</span><span id="line-102"> void shutdown() throws IOException {</span> |
| <span class="source-line-no">103</span><span id="line-103"> WALProvider provider = this.holder.get();</span> |
| <span class="source-line-no">104</span><span id="line-104"> if (provider != null) {</span> |
| <span class="source-line-no">105</span><span id="line-105"> provider.shutdown();</span> |
| <span class="source-line-no">106</span><span id="line-106"> }</span> |
| <span class="source-line-no">107</span><span id="line-107"> }</span> |
| <span class="source-line-no">108</span><span id="line-108">}</span> |
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| </pre> |
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