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<a class="jxr_linenumber" name="1" href="#1">1</a> <em class="jxr_comment">/*</em>
<a class="jxr_linenumber" name="2" href="#2">2</a> <em class="jxr_comment"> * Licensed to the Apache Software Foundation (ASF) under one</em>
<a class="jxr_linenumber" name="3" href="#3">3</a> <em class="jxr_comment"> * or more contributor license agreements. See the NOTICE file</em>
<a class="jxr_linenumber" name="4" href="#4">4</a> <em class="jxr_comment"> * distributed with this work for additional information</em>
<a class="jxr_linenumber" name="5" href="#5">5</a> <em class="jxr_comment"> * regarding copyright ownership. The ASF licenses this file</em>
<a class="jxr_linenumber" name="6" href="#6">6</a> <em class="jxr_comment"> * to you under the Apache License, Version 2.0 (the</em>
<a class="jxr_linenumber" name="7" href="#7">7</a> <em class="jxr_comment"> * "License"); you may not use this file except in compliance</em>
<a class="jxr_linenumber" name="8" href="#8">8</a> <em class="jxr_comment"> * with the License. You may obtain a copy of the License at</em>
<a class="jxr_linenumber" name="9" href="#9">9</a> <em class="jxr_comment"> *</em>
<a class="jxr_linenumber" name="10" href="#10">10</a> <em class="jxr_comment"> * <a href="http://www.apache.org/licenses/LICENSE-2.0" target="alexandria_uri">http://www.apache.org/licenses/LICENSE-2.0</a></em>
<a class="jxr_linenumber" name="11" href="#11">11</a> <em class="jxr_comment"> *</em>
<a class="jxr_linenumber" name="12" href="#12">12</a> <em class="jxr_comment"> * Unless required by applicable law or agreed to in writing, software</em>
<a class="jxr_linenumber" name="13" href="#13">13</a> <em class="jxr_comment"> * distributed under the License is distributed on an "AS IS" BASIS,</em>
<a class="jxr_linenumber" name="14" href="#14">14</a> <em class="jxr_comment"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</em>
<a class="jxr_linenumber" name="15" href="#15">15</a> <em class="jxr_comment"> * See the License for the specific language governing permissions and</em>
<a class="jxr_linenumber" name="16" href="#16">16</a> <em class="jxr_comment"> * limitations under the License.</em>
<a class="jxr_linenumber" name="17" href="#17">17</a> <em class="jxr_comment"> */</em>
<a class="jxr_linenumber" name="18" href="#18">18</a> <strong class="jxr_keyword">package</strong> org.apache.omid.examples;
<a class="jxr_linenumber" name="19" href="#19">19</a>
<a class="jxr_linenumber" name="20" href="#20">20</a> <strong class="jxr_keyword">import</strong> java.io.IOException;
<a class="jxr_linenumber" name="21" href="#21">21</a> <strong class="jxr_keyword">import</strong> java.util.Arrays;
<a class="jxr_linenumber" name="22" href="#22">22</a>
<a class="jxr_linenumber" name="23" href="#23">23</a> <strong class="jxr_keyword">import</strong> org.apache.commons.lang.StringUtils;
<a class="jxr_linenumber" name="24" href="#24">24</a> <strong class="jxr_keyword">import</strong> org.apache.hadoop.hbase.client.ConnectionFactory;
<a class="jxr_linenumber" name="25" href="#25">25</a> <strong class="jxr_keyword">import</strong> org.apache.hadoop.hbase.client.Get;
<a class="jxr_linenumber" name="26" href="#26">26</a> <strong class="jxr_keyword">import</strong> org.apache.hadoop.hbase.client.Put;
<a class="jxr_linenumber" name="27" href="#27">27</a> <strong class="jxr_keyword">import</strong> org.apache.hadoop.hbase.client.Result;
<a class="jxr_linenumber" name="28" href="#28">28</a> <strong class="jxr_keyword">import</strong> org.apache.hadoop.hbase.util.Bytes;
<a class="jxr_linenumber" name="29" href="#29">29</a> <strong class="jxr_keyword">import</strong> org.apache.omid.transaction.HBaseTransactionManager;
<a class="jxr_linenumber" name="30" href="#30">30</a> <strong class="jxr_keyword">import</strong> org.apache.omid.transaction.RollbackException;
<a class="jxr_linenumber" name="31" href="#31">31</a> <strong class="jxr_keyword">import</strong> org.apache.omid.transaction.TTable;
<a class="jxr_linenumber" name="32" href="#32">32</a> <strong class="jxr_keyword">import</strong> org.apache.omid.transaction.Transaction;
<a class="jxr_linenumber" name="33" href="#33">33</a> <strong class="jxr_keyword">import</strong> org.apache.omid.transaction.TransactionManager;
<a class="jxr_linenumber" name="34" href="#34">34</a> <strong class="jxr_keyword">import</strong> org.slf4j.Logger;
<a class="jxr_linenumber" name="35" href="#35">35</a> <strong class="jxr_keyword">import</strong> org.slf4j.LoggerFactory;
<a class="jxr_linenumber" name="36" href="#36">36</a>
<a class="jxr_linenumber" name="37" href="#37">37</a> <strong class="jxr_keyword">import</strong> org.apache.phoenix.thirdparty.com.google.common.base.Preconditions;
<a class="jxr_linenumber" name="38" href="#38">38</a>
<a class="jxr_linenumber" name="39" href="#39">39</a> <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="40" href="#40">40</a> <em class="jxr_javadoccomment"> * ****************************************************************************************************************</em>
<a class="jxr_linenumber" name="41" href="#41">41</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="42" href="#42">42</a> <em class="jxr_javadoccomment"> * Example code which demonstrates the preservation of Snapshot Isolation when writing shared data concurrently</em>
<a class="jxr_linenumber" name="43" href="#43">43</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="44" href="#44">44</a> <em class="jxr_javadoccomment"> * ****************************************************************************************************************</em>
<a class="jxr_linenumber" name="45" href="#45">45</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="46" href="#46">46</a> <em class="jxr_javadoccomment"> * Please @see{BasicExample} first</em>
<a class="jxr_linenumber" name="47" href="#47">47</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="48" href="#48">48</a> <em class="jxr_javadoccomment"> * In the code below, two concurrent transactions (Tx1 and Tx2), try to update the same column in HBase. This will</em>
<a class="jxr_linenumber" name="49" href="#49">49</a> <em class="jxr_javadoccomment"> * result in the rollback of Tx2 -the last one trying to commit- due to conflicts in the writeset with the previously</em>
<a class="jxr_linenumber" name="50" href="#50">50</a> <em class="jxr_javadoccomment"> * committed transaction Tx1. Also shows how Tx2 reads the right values from its own snapshot in HBase data.</em>
<a class="jxr_linenumber" name="51" href="#51">51</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="52" href="#52">52</a> <em class="jxr_javadoccomment"> * After building the package with 'mvn clean package' find the resulting examples-{version}-bin.tar.gz file in the</em>
<a class="jxr_linenumber" name="53" href="#53">53</a> <em class="jxr_javadoccomment"> * 'examples/target' folder. Copy it to the target host and expand with 'tar -zxvf examples-{version}-bin.tar.gz'.</em>
<a class="jxr_linenumber" name="54" href="#54">54</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="55" href="#55">55</a> <em class="jxr_javadoccomment"> * Make sure that 'hbase-site.xml' and 'core-site.xml' are either in classpath (see run.sh) or explicitly referenced via</em>
<a class="jxr_linenumber" name="56" href="#56">56</a> <em class="jxr_javadoccomment"> * command line arguments. If a secure HBase deployment is needed, use also command line arguments to specify the</em>
<a class="jxr_linenumber" name="57" href="#57">57</a> <em class="jxr_javadoccomment"> * principal (user) and keytab file.</em>
<a class="jxr_linenumber" name="58" href="#58">58</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="59" href="#59">59</a> <em class="jxr_javadoccomment"> * The example requires a user table to perform transactional read/write operations. A table is already specified in the</em>
<a class="jxr_linenumber" name="60" href="#60">60</a> <em class="jxr_javadoccomment"> * default configuration, and can be created with the following command using the 'hbase shell':</em>
<a class="jxr_linenumber" name="61" href="#61">61</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="62" href="#62">62</a> <em class="jxr_javadoccomment"> * &lt;pre&gt;</em>
<a class="jxr_linenumber" name="63" href="#63">63</a> <em class="jxr_javadoccomment"> * create 'MY_TX_TABLE', {NAME =&amp;gt; 'MY_CF', VERSIONS =&amp;gt; '2147483647', TTL =&amp;gt; '2147483647'}</em>
<a class="jxr_linenumber" name="64" href="#64">64</a> <em class="jxr_javadoccomment"> * &lt;/pre&gt;</em>
<a class="jxr_linenumber" name="65" href="#65">65</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="66" href="#66">66</a> <em class="jxr_javadoccomment"> * Make sure that the principal/user has RW permissions for the given table using also the 'hbase shell':</em>
<a class="jxr_linenumber" name="67" href="#67">67</a> <em class="jxr_javadoccomment"> * &lt;pre&gt;</em>
<a class="jxr_linenumber" name="68" href="#68">68</a> <em class="jxr_javadoccomment"> * grant '{principal/user}', 'RW', 'MY_TX_TABLE'</em>
<a class="jxr_linenumber" name="69" href="#69">69</a> <em class="jxr_javadoccomment"> * &lt;/pre&gt;</em>
<a class="jxr_linenumber" name="70" href="#70">70</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="71" href="#71">71</a> <em class="jxr_javadoccomment"> * Alternatively, a table with a column family already created can be used by specifying the table name and column</em>
<a class="jxr_linenumber" name="72" href="#72">72</a> <em class="jxr_javadoccomment"> * family identifiers using the command line arguments (see details also in 'run.sh') If a table namespace is required,</em>
<a class="jxr_linenumber" name="73" href="#73">73</a> <em class="jxr_javadoccomment"> * specify it like this: 'namespace:table_name'</em>
<a class="jxr_linenumber" name="74" href="#74">74</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="75" href="#75">75</a> <em class="jxr_javadoccomment"> * Finally, run the example using the 'run.sh' script without arguments or specifying the necessary configuration</em>
<a class="jxr_linenumber" name="76" href="#76">76</a> <em class="jxr_javadoccomment"> * parameters if required.</em>
<a class="jxr_linenumber" name="77" href="#77">77</a> <em class="jxr_javadoccomment"> */</em>
<a class="jxr_linenumber" name="78" href="#78">78</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">class</strong> <a href="../../../../org/apache/omid/examples/SnapshotIsolationExample.html">SnapshotIsolationExample</a> {
<a class="jxr_linenumber" name="79" href="#79">79</a>
<a class="jxr_linenumber" name="80" href="#80">80</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> Logger LOG = LoggerFactory.getLogger(SnapshotIsolationExample.<strong class="jxr_keyword">class</strong>);
<a class="jxr_linenumber" name="81" href="#81">81</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> byte[] qualifier;
<a class="jxr_linenumber" name="82" href="#82">82</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> byte[] initialData;
<a class="jxr_linenumber" name="83" href="#83">83</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> byte[] dataValue1;
<a class="jxr_linenumber" name="84" href="#84">84</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> byte[] dataValue2;
<a class="jxr_linenumber" name="85" href="#85">85</a> <strong class="jxr_keyword">private</strong> <a href="../../../../org/apache/omid/examples/RowIdGenerator.html">RowIdGenerator</a> rowIdGenerator = <strong class="jxr_keyword">new</strong> <a href="../../../../org/apache/omid/examples/SnapshotIsolationExample.html">StaticRowIdGenerator</a>();
<a class="jxr_linenumber" name="86" href="#86">86</a> <strong class="jxr_keyword">private</strong> String userTableName;
<a class="jxr_linenumber" name="87" href="#87">87</a> <strong class="jxr_keyword">private</strong> byte[] family;
<a class="jxr_linenumber" name="88" href="#88">88</a> <strong class="jxr_keyword">private</strong> <a href="../../../../org/apache/omid/transaction/TransactionManager.html">TransactionManager</a> tm;
<a class="jxr_linenumber" name="89" href="#89">89</a> <strong class="jxr_keyword">private</strong> <a href="../../../../org/apache/omid/transaction/TTable.html">TTable</a> txTable;
<a class="jxr_linenumber" name="90" href="#90">90</a>
<a class="jxr_linenumber" name="91" href="#91">91</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">void</strong> main(String[] args) <strong class="jxr_keyword">throws</strong> Exception {
<a class="jxr_linenumber" name="92" href="#92">92</a> <a href="../../../../org/apache/omid/examples/SnapshotIsolationExample.html">SnapshotIsolationExample</a> example = <strong class="jxr_keyword">new</strong> <a href="../../../../org/apache/omid/examples/SnapshotIsolationExample.html">SnapshotIsolationExample</a>(args);
<a class="jxr_linenumber" name="93" href="#93">93</a> example.execute();
<a class="jxr_linenumber" name="94" href="#94">94</a> example.close();
<a class="jxr_linenumber" name="95" href="#95">95</a> }
<a class="jxr_linenumber" name="96" href="#96">96</a>
<a class="jxr_linenumber" name="97" href="#97">97</a> <a href="../../../../org/apache/omid/examples/SnapshotIsolationExample.html">SnapshotIsolationExample</a>(String[] args) <strong class="jxr_keyword">throws</strong> IOException, InterruptedException {
<a class="jxr_linenumber" name="98" href="#98">98</a> LOG.info(<span class="jxr_string">"Parsing the command line arguments"</span>);
<a class="jxr_linenumber" name="99" href="#99">99</a> userTableName = <span class="jxr_string">"MY_TX_TABLE"</span>;
<a class="jxr_linenumber" name="100" href="#100">100</a> <strong class="jxr_keyword">if</strong> (args != <strong class="jxr_keyword">null</strong> &amp;&amp; args.length &gt; 0 &amp;&amp; StringUtils.isNotEmpty(args[0])) {
<a class="jxr_linenumber" name="101" href="#101">101</a> userTableName = args[0];
<a class="jxr_linenumber" name="102" href="#102">102</a> }
<a class="jxr_linenumber" name="103" href="#103">103</a> family = Bytes.toBytes(<span class="jxr_string">"MY_CF"</span>);
<a class="jxr_linenumber" name="104" href="#104">104</a> <strong class="jxr_keyword">if</strong> (args != <strong class="jxr_keyword">null</strong> &amp;&amp; args.length &gt; 1 &amp;&amp; StringUtils.isNotEmpty(args[1])) {
<a class="jxr_linenumber" name="105" href="#105">105</a> family = Bytes.toBytes(args[1]);
<a class="jxr_linenumber" name="106" href="#106">106</a> }
<a class="jxr_linenumber" name="107" href="#107">107</a> LOG.info(<span class="jxr_string">"Table '{}', column family '{}'"</span>, userTableName, Bytes.toString(family));
<a class="jxr_linenumber" name="108" href="#108">108</a>
<a class="jxr_linenumber" name="109" href="#109">109</a> qualifier = Bytes.toBytes(<span class="jxr_string">"MY_Q"</span>);
<a class="jxr_linenumber" name="110" href="#110">110</a> initialData = Bytes.toBytes(<span class="jxr_string">"initialVal"</span>);
<a class="jxr_linenumber" name="111" href="#111">111</a> dataValue1 = Bytes.toBytes(<span class="jxr_string">"val1"</span>);
<a class="jxr_linenumber" name="112" href="#112">112</a> dataValue2 = Bytes.toBytes(<span class="jxr_string">"val2"</span>);
<a class="jxr_linenumber" name="113" href="#113">113</a>
<a class="jxr_linenumber" name="114" href="#114">114</a> LOG.info(<span class="jxr_string">"--------"</span>);
<a class="jxr_linenumber" name="115" href="#115">115</a> LOG.info(<span class="jxr_string">"NOTE: All Transactions in the Example access column {}:{}/{}/{} [TABLE:ROW/CF/Q]"</span>,
<a class="jxr_linenumber" name="116" href="#116">116</a> userTableName, Bytes.toString(rowIdGenerator.getRowId()), Bytes.toString(family),
<a class="jxr_linenumber" name="117" href="#117">117</a> Bytes.toString(qualifier));
<a class="jxr_linenumber" name="118" href="#118">118</a> LOG.info(<span class="jxr_string">"--------"</span>);
<a class="jxr_linenumber" name="119" href="#119">119</a>
<a class="jxr_linenumber" name="120" href="#120">120</a> LOG.info(<span class="jxr_string">"Creating access to Omid Transaction Manager &amp; Transactional Table '{}'"</span>, userTableName);
<a class="jxr_linenumber" name="121" href="#121">121</a> tm = HBaseTransactionManager.newInstance();
<a class="jxr_linenumber" name="122" href="#122">122</a> txTable = <strong class="jxr_keyword">new</strong> <a href="../../../../org/apache/omid/transaction/TTable.html">TTable</a>(ConnectionFactory.createConnection(), userTableName);
<a class="jxr_linenumber" name="123" href="#123">123</a> }
<a class="jxr_linenumber" name="124" href="#124">124</a>
<a class="jxr_linenumber" name="125" href="#125">125</a> <strong class="jxr_keyword">void</strong> execute() <strong class="jxr_keyword">throws</strong> IOException, RollbackException {
<a class="jxr_linenumber" name="126" href="#126">126</a>
<a class="jxr_linenumber" name="127" href="#127">127</a> <em class="jxr_comment">// A transaction Tx0 sets an initial value to a particular column in an specific row</em>
<a class="jxr_linenumber" name="128" href="#128">128</a> <a href="../../../../org/apache/omid/transaction/Transaction.html">Transaction</a> tx0 = tm.begin();
<a class="jxr_linenumber" name="129" href="#129">129</a> byte[] rowId = rowIdGenerator.getRowId();
<a class="jxr_linenumber" name="130" href="#130">130</a> Put initialPut = <strong class="jxr_keyword">new</strong> Put(rowId);
<a class="jxr_linenumber" name="131" href="#131">131</a> initialPut.addColumn(family, qualifier, initialData);
<a class="jxr_linenumber" name="132" href="#132">132</a> txTable.put(tx0, initialPut);
<a class="jxr_linenumber" name="133" href="#133">133</a> tm.commit(tx0);
<a class="jxr_linenumber" name="134" href="#134">134</a> LOG.info(<span class="jxr_string">"Initial Transaction {} COMMITTED. Base value written in {}:{}/{}/{} = {}"</span>,
<a class="jxr_linenumber" name="135" href="#135">135</a> tx0, userTableName, Bytes.toString(rowId), Bytes.toString(family),
<a class="jxr_linenumber" name="136" href="#136">136</a> Bytes.toString(qualifier), Bytes.toString(initialData));
<a class="jxr_linenumber" name="137" href="#137">137</a>
<a class="jxr_linenumber" name="138" href="#138">138</a> <em class="jxr_comment">// Transaction Tx1 starts, creates its own snapshot of the current data in HBase and writes new data</em>
<a class="jxr_linenumber" name="139" href="#139">139</a> <a href="../../../../org/apache/omid/transaction/Transaction.html">Transaction</a> tx1 = tm.begin();
<a class="jxr_linenumber" name="140" href="#140">140</a> LOG.info(<span class="jxr_string">"Transaction {} STARTED"</span>, tx1);
<a class="jxr_linenumber" name="141" href="#141">141</a> Put tx1Put = <strong class="jxr_keyword">new</strong> Put(rowId);
<a class="jxr_linenumber" name="142" href="#142">142</a> tx1Put.addColumn(family, qualifier, dataValue1);
<a class="jxr_linenumber" name="143" href="#143">143</a> txTable.put(tx1, tx1Put);
<a class="jxr_linenumber" name="144" href="#144">144</a> LOG.info(<span class="jxr_string">"Transaction {} updates base value in {}:{}/{}/{} = {} in its own Snapshot"</span>,
<a class="jxr_linenumber" name="145" href="#145">145</a> tx1, userTableName, Bytes.toString(rowId), Bytes.toString(family),
<a class="jxr_linenumber" name="146" href="#146">146</a> Bytes.toString(qualifier), Bytes.toString(dataValue1));
<a class="jxr_linenumber" name="147" href="#147">147</a>
<a class="jxr_linenumber" name="148" href="#148">148</a> <em class="jxr_comment">// A concurrent transaction Tx2 starts, creates its own snapshot and reads the column value</em>
<a class="jxr_linenumber" name="149" href="#149">149</a> <a href="../../../../org/apache/omid/transaction/Transaction.html">Transaction</a> tx2 = tm.begin();
<a class="jxr_linenumber" name="150" href="#150">150</a> LOG.info(<span class="jxr_string">"Concurrent Transaction {} STARTED"</span>, tx2);
<a class="jxr_linenumber" name="151" href="#151">151</a> Get tx2Get = <strong class="jxr_keyword">new</strong> Get(rowId);
<a class="jxr_linenumber" name="152" href="#152">152</a> tx2Get.addColumn(family, qualifier);
<a class="jxr_linenumber" name="153" href="#153">153</a> Result tx2GetResult = txTable.get(tx2, tx2Get);
<a class="jxr_linenumber" name="154" href="#154">154</a> Preconditions.checkState(Arrays.equals(tx2GetResult.value(), initialData),
<a class="jxr_linenumber" name="155" href="#155">155</a> <span class="jxr_string">"As Tx1 is not yet committed, Tx2 should read the value set by Tx0 not the value written by Tx1"</span>);
<a class="jxr_linenumber" name="156" href="#156">156</a> LOG.info(
<a class="jxr_linenumber" name="157" href="#157">157</a> <span class="jxr_string">"Concurrent Transaction {} should read base value in {}:{}/{}/{} from its Snapshot | Value read = {}"</span>,
<a class="jxr_linenumber" name="158" href="#158">158</a> tx2, userTableName, Bytes.toString(rowId), Bytes.toString(family),
<a class="jxr_linenumber" name="159" href="#159">159</a> Bytes.toString(qualifier), Bytes.toString(tx2GetResult.value()));
<a class="jxr_linenumber" name="160" href="#160">160</a>
<a class="jxr_linenumber" name="161" href="#161">161</a> <em class="jxr_comment">// Transaction Tx1 tries to commit and as there're no conflicting changes, persists the new value in HBase</em>
<a class="jxr_linenumber" name="162" href="#162">162</a> tm.commit(tx1);
<a class="jxr_linenumber" name="163" href="#163">163</a> LOG.info(<span class="jxr_string">"Transaction {} COMMITTED. New column value {}:{}/{}/{} = {}"</span>,
<a class="jxr_linenumber" name="164" href="#164">164</a> tx1, userTableName, Bytes.toString(rowId), Bytes.toString(family),
<a class="jxr_linenumber" name="165" href="#165">165</a> Bytes.toString(qualifier), Bytes.toString(dataValue1));
<a class="jxr_linenumber" name="166" href="#166">166</a>
<a class="jxr_linenumber" name="167" href="#167">167</a> <em class="jxr_comment">// Tx2 reading again after Tx1 commit must read data from its snapshot...</em>
<a class="jxr_linenumber" name="168" href="#168">168</a> tx2Get = <strong class="jxr_keyword">new</strong> Get(rowId);
<a class="jxr_linenumber" name="169" href="#169">169</a> tx2Get.addColumn(family, qualifier);
<a class="jxr_linenumber" name="170" href="#170">170</a> tx2GetResult = txTable.get(tx2, tx2Get);
<a class="jxr_linenumber" name="171" href="#171">171</a> <em class="jxr_comment">// ...so it must read the initial value written by Tx0</em>
<a class="jxr_linenumber" name="172" href="#172">172</a> LOG.info(
<a class="jxr_linenumber" name="173" href="#173">173</a> <span class="jxr_string">"Concurrent Transaction {} should read again base value in {}:{}/{}/{} from its Snapshot | Value read = {}"</span>,
<a class="jxr_linenumber" name="174" href="#174">174</a> tx2, userTableName, Bytes.toString(rowId), Bytes.toString(family),
<a class="jxr_linenumber" name="175" href="#175">175</a> Bytes.toString(qualifier), Bytes.toString(tx2GetResult.value()));
<a class="jxr_linenumber" name="176" href="#176">176</a> Preconditions.checkState(Arrays.equals(tx2GetResult.value(), initialData),
<a class="jxr_linenumber" name="177" href="#177">177</a> <span class="jxr_string">"Tx2 must read the initial value written by Tx0"</span>);
<a class="jxr_linenumber" name="178" href="#178">178</a>
<a class="jxr_linenumber" name="179" href="#179">179</a> <em class="jxr_comment">// Tx2 tries to write the column written by the committed concurrent transaction Tx1...</em>
<a class="jxr_linenumber" name="180" href="#180">180</a> Put tx2Put = <strong class="jxr_keyword">new</strong> Put(rowId);
<a class="jxr_linenumber" name="181" href="#181">181</a> tx2Put.addColumn(family, qualifier, dataValue2);
<a class="jxr_linenumber" name="182" href="#182">182</a> txTable.put(tx2, tx2Put);
<a class="jxr_linenumber" name="183" href="#183">183</a> LOG.info(
<a class="jxr_linenumber" name="184" href="#184">184</a> <span class="jxr_string">"Concurrent Transaction {} updates {}:{}/{}/{} = {} in its own Snapshot (Will conflict with {} at commit time)"</span>,
<a class="jxr_linenumber" name="185" href="#185">185</a> tx2, userTableName, Bytes.toString(rowId), Bytes.toString(family),
<a class="jxr_linenumber" name="186" href="#186">186</a> Bytes.toString(qualifier), Bytes.toString(dataValue1), tx1);
<a class="jxr_linenumber" name="187" href="#187">187</a>
<a class="jxr_linenumber" name="188" href="#188">188</a> <em class="jxr_comment">// ... and when committing, Tx2 has to abort due to concurrent conflicts with committed transaction Tx1</em>
<a class="jxr_linenumber" name="189" href="#189">189</a> <strong class="jxr_keyword">try</strong> {
<a class="jxr_linenumber" name="190" href="#190">190</a> LOG.info(<span class="jxr_string">"Concurrent Transaction {} TRYING TO COMMIT"</span>, tx2);
<a class="jxr_linenumber" name="191" href="#191">191</a> tm.commit(tx2);
<a class="jxr_linenumber" name="192" href="#192">192</a> <em class="jxr_comment">// should throw an exception</em>
<a class="jxr_linenumber" name="193" href="#193">193</a> Preconditions.checkState(false, <span class="jxr_string">"Should have thrown RollbackException"</span>);
<a class="jxr_linenumber" name="194" href="#194">194</a> } <strong class="jxr_keyword">catch</strong> (RollbackException e) {
<a class="jxr_linenumber" name="195" href="#195">195</a> LOG.info(<span class="jxr_string">"Concurrent Transaction {} ROLLED-BACK : {}"</span>, tx2, e.getMessage());
<a class="jxr_linenumber" name="196" href="#196">196</a> }
<a class="jxr_linenumber" name="197" href="#197">197</a> }
<a class="jxr_linenumber" name="198" href="#198">198</a>
<a class="jxr_linenumber" name="199" href="#199">199</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">void</strong> close() <strong class="jxr_keyword">throws</strong> IOException {
<a class="jxr_linenumber" name="200" href="#200">200</a> tm.close();
<a class="jxr_linenumber" name="201" href="#201">201</a> txTable.close();
<a class="jxr_linenumber" name="202" href="#202">202</a> }
<a class="jxr_linenumber" name="203" href="#203">203</a>
<a class="jxr_linenumber" name="204" href="#204">204</a>
<a class="jxr_linenumber" name="205" href="#205">205</a> <strong class="jxr_keyword">void</strong> setRowIdGenerator(<a href="../../../../org/apache/omid/examples/RowIdGenerator.html">RowIdGenerator</a> rowIdGenerator) {
<a class="jxr_linenumber" name="206" href="#206">206</a> <strong class="jxr_keyword">this</strong>.rowIdGenerator = rowIdGenerator;
<a class="jxr_linenumber" name="207" href="#207">207</a> }
<a class="jxr_linenumber" name="208" href="#208">208</a>
<a class="jxr_linenumber" name="209" href="#209">209</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">class</strong> <a href="../../../../org/apache/omid/examples/SnapshotIsolationExample.html">StaticRowIdGenerator</a> <strong class="jxr_keyword">implements</strong> <a href="../../../../org/apache/omid/examples/RowIdGenerator.html">RowIdGenerator</a> {
<a class="jxr_linenumber" name="210" href="#210">210</a>
<a class="jxr_linenumber" name="211" href="#211">211</a> @Override
<a class="jxr_linenumber" name="212" href="#212">212</a> <strong class="jxr_keyword">public</strong> byte[] getRowId() {
<a class="jxr_linenumber" name="213" href="#213">213</a> <strong class="jxr_keyword">return</strong> Bytes.toBytes(<span class="jxr_string">"EXAMPLE_ROW"</span>);
<a class="jxr_linenumber" name="214" href="#214">214</a> }
<a class="jxr_linenumber" name="215" href="#215">215</a> }
<a class="jxr_linenumber" name="216" href="#216">216</a> }
<a class="jxr_linenumber" name="217" href="#217">217</a>
</pre>
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