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<FONT color="green">001</FONT>    /**<a name="line.1"></a>
<FONT color="green">002</FONT>     * Licensed to the Apache Software Foundation (ASF) under one<a name="line.2"></a>
<FONT color="green">003</FONT>     * or more contributor license agreements.  See the NOTICE file<a name="line.3"></a>
<FONT color="green">004</FONT>     * distributed with this work for additional information<a name="line.4"></a>
<FONT color="green">005</FONT>     * regarding copyright ownership.  The ASF licenses this file<a name="line.5"></a>
<FONT color="green">006</FONT>     * to you under the Apache License, Version 2.0 (the<a name="line.6"></a>
<FONT color="green">007</FONT>     * "License"); you may not use this file except in compliance<a name="line.7"></a>
<FONT color="green">008</FONT>     * with the License.  You may obtain a copy of the License at<a name="line.8"></a>
<FONT color="green">009</FONT>     *<a name="line.9"></a>
<FONT color="green">010</FONT>     *     http://www.apache.org/licenses/LICENSE-2.0<a name="line.10"></a>
<FONT color="green">011</FONT>     *<a name="line.11"></a>
<FONT color="green">012</FONT>     * Unless required by applicable law or agreed to in writing, software<a name="line.12"></a>
<FONT color="green">013</FONT>     * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.13"></a>
<FONT color="green">014</FONT>     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.14"></a>
<FONT color="green">015</FONT>     * See the License for the specific language governing permissions and<a name="line.15"></a>
<FONT color="green">016</FONT>     * limitations under the License.<a name="line.16"></a>
<FONT color="green">017</FONT>     */<a name="line.17"></a>
<FONT color="green">018</FONT>    <a name="line.18"></a>
<FONT color="green">019</FONT>    package org.apache.hadoop.mapreduce.lib.db;<a name="line.19"></a>
<FONT color="green">020</FONT>    <a name="line.20"></a>
<FONT color="green">021</FONT>    import java.sql.ResultSet;<a name="line.21"></a>
<FONT color="green">022</FONT>    import java.sql.SQLException;<a name="line.22"></a>
<FONT color="green">023</FONT>    import java.math.BigDecimal;<a name="line.23"></a>
<FONT color="green">024</FONT>    import java.util.ArrayList;<a name="line.24"></a>
<FONT color="green">025</FONT>    import java.util.Iterator;<a name="line.25"></a>
<FONT color="green">026</FONT>    import java.util.List;<a name="line.26"></a>
<FONT color="green">027</FONT>    <a name="line.27"></a>
<FONT color="green">028</FONT>    import org.apache.commons.logging.Log;<a name="line.28"></a>
<FONT color="green">029</FONT>    import org.apache.commons.logging.LogFactory;<a name="line.29"></a>
<FONT color="green">030</FONT>    <a name="line.30"></a>
<FONT color="green">031</FONT>    import org.apache.hadoop.classification.InterfaceAudience;<a name="line.31"></a>
<FONT color="green">032</FONT>    import org.apache.hadoop.classification.InterfaceStability;<a name="line.32"></a>
<FONT color="green">033</FONT>    import org.apache.hadoop.conf.Configuration;<a name="line.33"></a>
<FONT color="green">034</FONT>    import org.apache.hadoop.mapreduce.InputSplit;<a name="line.34"></a>
<FONT color="green">035</FONT>    import org.apache.hadoop.mapreduce.MRJobConfig;<a name="line.35"></a>
<FONT color="green">036</FONT>    <a name="line.36"></a>
<FONT color="green">037</FONT>    /**<a name="line.37"></a>
<FONT color="green">038</FONT>     * Implement DBSplitter over text strings.<a name="line.38"></a>
<FONT color="green">039</FONT>     */<a name="line.39"></a>
<FONT color="green">040</FONT>    @InterfaceAudience.Public<a name="line.40"></a>
<FONT color="green">041</FONT>    @InterfaceStability.Evolving<a name="line.41"></a>
<FONT color="green">042</FONT>    public class TextSplitter extends BigDecimalSplitter {<a name="line.42"></a>
<FONT color="green">043</FONT>    <a name="line.43"></a>
<FONT color="green">044</FONT>      private static final Log LOG = LogFactory.getLog(TextSplitter.class);<a name="line.44"></a>
<FONT color="green">045</FONT>    <a name="line.45"></a>
<FONT color="green">046</FONT>      /**<a name="line.46"></a>
<FONT color="green">047</FONT>       * This method needs to determine the splits between two user-provided strings.<a name="line.47"></a>
<FONT color="green">048</FONT>       * In the case where the user's strings are 'A' and 'Z', this is not hard; we <a name="line.48"></a>
<FONT color="green">049</FONT>       * could create two splits from ['A', 'M') and ['M', 'Z'], 26 splits for strings<a name="line.49"></a>
<FONT color="green">050</FONT>       * beginning with each letter, etc.<a name="line.50"></a>
<FONT color="green">051</FONT>       *<a name="line.51"></a>
<FONT color="green">052</FONT>       * If a user has provided us with the strings "Ham" and "Haze", however, we need<a name="line.52"></a>
<FONT color="green">053</FONT>       * to create splits that differ in the third letter.<a name="line.53"></a>
<FONT color="green">054</FONT>       *<a name="line.54"></a>
<FONT color="green">055</FONT>       * The algorithm used is as follows:<a name="line.55"></a>
<FONT color="green">056</FONT>       * Since there are 2**16 unicode characters, we interpret characters as digits in<a name="line.56"></a>
<FONT color="green">057</FONT>       * base 65536. Given a string 's' containing characters s_0, s_1 .. s_n, we interpret<a name="line.57"></a>
<FONT color="green">058</FONT>       * the string as the number: 0.s_0 s_1 s_2.. s_n in base 65536. Having mapped the<a name="line.58"></a>
<FONT color="green">059</FONT>       * low and high strings into floating-point values, we then use the BigDecimalSplitter<a name="line.59"></a>
<FONT color="green">060</FONT>       * to establish the even split points, then map the resulting floating point values<a name="line.60"></a>
<FONT color="green">061</FONT>       * back into strings.<a name="line.61"></a>
<FONT color="green">062</FONT>       */<a name="line.62"></a>
<FONT color="green">063</FONT>      public List&lt;InputSplit&gt; split(Configuration conf, ResultSet results, String colName)<a name="line.63"></a>
<FONT color="green">064</FONT>          throws SQLException {<a name="line.64"></a>
<FONT color="green">065</FONT>    <a name="line.65"></a>
<FONT color="green">066</FONT>        LOG.warn("Generating splits for a textual index column.");<a name="line.66"></a>
<FONT color="green">067</FONT>        LOG.warn("If your database sorts in a case-insensitive order, "<a name="line.67"></a>
<FONT color="green">068</FONT>            + "this may result in a partial import or duplicate records.");<a name="line.68"></a>
<FONT color="green">069</FONT>        LOG.warn("You are strongly encouraged to choose an integral split column.");<a name="line.69"></a>
<FONT color="green">070</FONT>    <a name="line.70"></a>
<FONT color="green">071</FONT>        String minString = results.getString(1);<a name="line.71"></a>
<FONT color="green">072</FONT>        String maxString = results.getString(2);<a name="line.72"></a>
<FONT color="green">073</FONT>    <a name="line.73"></a>
<FONT color="green">074</FONT>        boolean minIsNull = false;<a name="line.74"></a>
<FONT color="green">075</FONT>    <a name="line.75"></a>
<FONT color="green">076</FONT>        // If the min value is null, switch it to an empty string instead for purposes<a name="line.76"></a>
<FONT color="green">077</FONT>        // of interpolation. Then add [null, null] as a special case split.<a name="line.77"></a>
<FONT color="green">078</FONT>        if (null == minString) {<a name="line.78"></a>
<FONT color="green">079</FONT>          minString = "";<a name="line.79"></a>
<FONT color="green">080</FONT>          minIsNull = true;<a name="line.80"></a>
<FONT color="green">081</FONT>        }<a name="line.81"></a>
<FONT color="green">082</FONT>    <a name="line.82"></a>
<FONT color="green">083</FONT>        if (null == maxString) {<a name="line.83"></a>
<FONT color="green">084</FONT>          // If the max string is null, then the min string has to be null too.<a name="line.84"></a>
<FONT color="green">085</FONT>          // Just return a special split for this case.<a name="line.85"></a>
<FONT color="green">086</FONT>          List&lt;InputSplit&gt; splits = new ArrayList&lt;InputSplit&gt;();<a name="line.86"></a>
<FONT color="green">087</FONT>          splits.add(new DataDrivenDBInputFormat.DataDrivenDBInputSplit(<a name="line.87"></a>
<FONT color="green">088</FONT>              colName + " IS NULL", colName + " IS NULL"));<a name="line.88"></a>
<FONT color="green">089</FONT>          return splits;<a name="line.89"></a>
<FONT color="green">090</FONT>        }<a name="line.90"></a>
<FONT color="green">091</FONT>    <a name="line.91"></a>
<FONT color="green">092</FONT>        // Use this as a hint. May need an extra task if the size doesn't<a name="line.92"></a>
<FONT color="green">093</FONT>        // divide cleanly.<a name="line.93"></a>
<FONT color="green">094</FONT>        int numSplits = conf.getInt(MRJobConfig.NUM_MAPS, 1);<a name="line.94"></a>
<FONT color="green">095</FONT>    <a name="line.95"></a>
<FONT color="green">096</FONT>        String lowClausePrefix = colName + " &gt;= '";<a name="line.96"></a>
<FONT color="green">097</FONT>        String highClausePrefix = colName + " &lt; '";<a name="line.97"></a>
<FONT color="green">098</FONT>    <a name="line.98"></a>
<FONT color="green">099</FONT>        // If there is a common prefix between minString and maxString, establish it<a name="line.99"></a>
<FONT color="green">100</FONT>        // and pull it out of minString and maxString.<a name="line.100"></a>
<FONT color="green">101</FONT>        int maxPrefixLen = Math.min(minString.length(), maxString.length());<a name="line.101"></a>
<FONT color="green">102</FONT>        int sharedLen;<a name="line.102"></a>
<FONT color="green">103</FONT>        for (sharedLen = 0; sharedLen &lt; maxPrefixLen; sharedLen++) {<a name="line.103"></a>
<FONT color="green">104</FONT>          char c1 = minString.charAt(sharedLen);<a name="line.104"></a>
<FONT color="green">105</FONT>          char c2 = maxString.charAt(sharedLen);<a name="line.105"></a>
<FONT color="green">106</FONT>          if (c1 != c2) {<a name="line.106"></a>
<FONT color="green">107</FONT>            break;<a name="line.107"></a>
<FONT color="green">108</FONT>          }<a name="line.108"></a>
<FONT color="green">109</FONT>        }<a name="line.109"></a>
<FONT color="green">110</FONT>    <a name="line.110"></a>
<FONT color="green">111</FONT>        // The common prefix has length 'sharedLen'. Extract it from both.<a name="line.111"></a>
<FONT color="green">112</FONT>        String commonPrefix = minString.substring(0, sharedLen);<a name="line.112"></a>
<FONT color="green">113</FONT>        minString = minString.substring(sharedLen);<a name="line.113"></a>
<FONT color="green">114</FONT>        maxString = maxString.substring(sharedLen);<a name="line.114"></a>
<FONT color="green">115</FONT>    <a name="line.115"></a>
<FONT color="green">116</FONT>        List&lt;String&gt; splitStrings = split(numSplits, minString, maxString, commonPrefix);<a name="line.116"></a>
<FONT color="green">117</FONT>        List&lt;InputSplit&gt; splits = new ArrayList&lt;InputSplit&gt;();<a name="line.117"></a>
<FONT color="green">118</FONT>    <a name="line.118"></a>
<FONT color="green">119</FONT>        // Convert the list of split point strings into an actual set of InputSplits.<a name="line.119"></a>
<FONT color="green">120</FONT>        String start = splitStrings.get(0);<a name="line.120"></a>
<FONT color="green">121</FONT>        for (int i = 1; i &lt; splitStrings.size(); i++) {<a name="line.121"></a>
<FONT color="green">122</FONT>          String end = splitStrings.get(i);<a name="line.122"></a>
<FONT color="green">123</FONT>    <a name="line.123"></a>
<FONT color="green">124</FONT>          if (i == splitStrings.size() - 1) {<a name="line.124"></a>
<FONT color="green">125</FONT>            // This is the last one; use a closed interval.<a name="line.125"></a>
<FONT color="green">126</FONT>            splits.add(new DataDrivenDBInputFormat.DataDrivenDBInputSplit(<a name="line.126"></a>
<FONT color="green">127</FONT>                lowClausePrefix + start + "'", colName + " &lt;= '" + end + "'"));<a name="line.127"></a>
<FONT color="green">128</FONT>          } else {<a name="line.128"></a>
<FONT color="green">129</FONT>            // Normal open-interval case.<a name="line.129"></a>
<FONT color="green">130</FONT>            splits.add(new DataDrivenDBInputFormat.DataDrivenDBInputSplit(<a name="line.130"></a>
<FONT color="green">131</FONT>                lowClausePrefix + start + "'", highClausePrefix + end + "'"));<a name="line.131"></a>
<FONT color="green">132</FONT>          }<a name="line.132"></a>
<FONT color="green">133</FONT>        }<a name="line.133"></a>
<FONT color="green">134</FONT>    <a name="line.134"></a>
<FONT color="green">135</FONT>        if (minIsNull) {<a name="line.135"></a>
<FONT color="green">136</FONT>          // Add the special null split at the end.<a name="line.136"></a>
<FONT color="green">137</FONT>          splits.add(new DataDrivenDBInputFormat.DataDrivenDBInputSplit(<a name="line.137"></a>
<FONT color="green">138</FONT>              colName + " IS NULL", colName + " IS NULL"));<a name="line.138"></a>
<FONT color="green">139</FONT>        }<a name="line.139"></a>
<FONT color="green">140</FONT>    <a name="line.140"></a>
<FONT color="green">141</FONT>        return splits;<a name="line.141"></a>
<FONT color="green">142</FONT>      }<a name="line.142"></a>
<FONT color="green">143</FONT>    <a name="line.143"></a>
<FONT color="green">144</FONT>      List&lt;String&gt; split(int numSplits, String minString, String maxString, String commonPrefix)<a name="line.144"></a>
<FONT color="green">145</FONT>          throws SQLException {<a name="line.145"></a>
<FONT color="green">146</FONT>    <a name="line.146"></a>
<FONT color="green">147</FONT>        BigDecimal minVal = stringToBigDecimal(minString);<a name="line.147"></a>
<FONT color="green">148</FONT>        BigDecimal maxVal = stringToBigDecimal(maxString);<a name="line.148"></a>
<FONT color="green">149</FONT>    <a name="line.149"></a>
<FONT color="green">150</FONT>        List&lt;BigDecimal&gt; splitPoints = split(new BigDecimal(numSplits), minVal, maxVal);<a name="line.150"></a>
<FONT color="green">151</FONT>        List&lt;String&gt; splitStrings = new ArrayList&lt;String&gt;();<a name="line.151"></a>
<FONT color="green">152</FONT>    <a name="line.152"></a>
<FONT color="green">153</FONT>        // Convert the BigDecimal splitPoints into their string representations.<a name="line.153"></a>
<FONT color="green">154</FONT>        for (BigDecimal bd : splitPoints) {<a name="line.154"></a>
<FONT color="green">155</FONT>          splitStrings.add(commonPrefix + bigDecimalToString(bd));<a name="line.155"></a>
<FONT color="green">156</FONT>        }<a name="line.156"></a>
<FONT color="green">157</FONT>    <a name="line.157"></a>
<FONT color="green">158</FONT>        // Make sure that our user-specified boundaries are the first and last entries<a name="line.158"></a>
<FONT color="green">159</FONT>        // in the array.<a name="line.159"></a>
<FONT color="green">160</FONT>        if (splitStrings.size() == 0 || !splitStrings.get(0).equals(commonPrefix + minString)) {<a name="line.160"></a>
<FONT color="green">161</FONT>          splitStrings.add(0, commonPrefix + minString);<a name="line.161"></a>
<FONT color="green">162</FONT>        }<a name="line.162"></a>
<FONT color="green">163</FONT>        if (splitStrings.size() == 1<a name="line.163"></a>
<FONT color="green">164</FONT>            || !splitStrings.get(splitStrings.size() - 1).equals(commonPrefix + maxString)) {<a name="line.164"></a>
<FONT color="green">165</FONT>          splitStrings.add(commonPrefix + maxString);<a name="line.165"></a>
<FONT color="green">166</FONT>        }<a name="line.166"></a>
<FONT color="green">167</FONT>    <a name="line.167"></a>
<FONT color="green">168</FONT>        return splitStrings;<a name="line.168"></a>
<FONT color="green">169</FONT>      }<a name="line.169"></a>
<FONT color="green">170</FONT>    <a name="line.170"></a>
<FONT color="green">171</FONT>      private final static BigDecimal ONE_PLACE = new BigDecimal(65536);<a name="line.171"></a>
<FONT color="green">172</FONT>    <a name="line.172"></a>
<FONT color="green">173</FONT>      // Maximum number of characters to convert. This is to prevent rounding errors<a name="line.173"></a>
<FONT color="green">174</FONT>      // or repeating fractions near the very bottom from getting out of control. Note<a name="line.174"></a>
<FONT color="green">175</FONT>      // that this still gives us a huge number of possible splits.<a name="line.175"></a>
<FONT color="green">176</FONT>      private final static int MAX_CHARS = 8;<a name="line.176"></a>
<FONT color="green">177</FONT>    <a name="line.177"></a>
<FONT color="green">178</FONT>      /**<a name="line.178"></a>
<FONT color="green">179</FONT>       * Return a BigDecimal representation of string 'str' suitable for use<a name="line.179"></a>
<FONT color="green">180</FONT>       * in a numerically-sorting order.<a name="line.180"></a>
<FONT color="green">181</FONT>       */<a name="line.181"></a>
<FONT color="green">182</FONT>      BigDecimal stringToBigDecimal(String str) {<a name="line.182"></a>
<FONT color="green">183</FONT>        BigDecimal result = BigDecimal.ZERO;<a name="line.183"></a>
<FONT color="green">184</FONT>        BigDecimal curPlace = ONE_PLACE; // start with 1/65536 to compute the first digit.<a name="line.184"></a>
<FONT color="green">185</FONT>    <a name="line.185"></a>
<FONT color="green">186</FONT>        int len = Math.min(str.length(), MAX_CHARS);<a name="line.186"></a>
<FONT color="green">187</FONT>    <a name="line.187"></a>
<FONT color="green">188</FONT>        for (int i = 0; i &lt; len; i++) {<a name="line.188"></a>
<FONT color="green">189</FONT>          int codePoint = str.codePointAt(i);<a name="line.189"></a>
<FONT color="green">190</FONT>          result = result.add(tryDivide(new BigDecimal(codePoint), curPlace));<a name="line.190"></a>
<FONT color="green">191</FONT>          // advance to the next less significant place. e.g., 1/(65536^2) for the second char.<a name="line.191"></a>
<FONT color="green">192</FONT>          curPlace = curPlace.multiply(ONE_PLACE);<a name="line.192"></a>
<FONT color="green">193</FONT>        }<a name="line.193"></a>
<FONT color="green">194</FONT>    <a name="line.194"></a>
<FONT color="green">195</FONT>        return result;<a name="line.195"></a>
<FONT color="green">196</FONT>      }<a name="line.196"></a>
<FONT color="green">197</FONT>    <a name="line.197"></a>
<FONT color="green">198</FONT>      /**<a name="line.198"></a>
<FONT color="green">199</FONT>       * Return the string encoded in a BigDecimal.<a name="line.199"></a>
<FONT color="green">200</FONT>       * Repeatedly multiply the input value by 65536; the integer portion after such a multiplication<a name="line.200"></a>
<FONT color="green">201</FONT>       * represents a single character in base 65536. Convert that back into a char and create a<a name="line.201"></a>
<FONT color="green">202</FONT>       * string out of these until we have no data left.<a name="line.202"></a>
<FONT color="green">203</FONT>       */<a name="line.203"></a>
<FONT color="green">204</FONT>      String bigDecimalToString(BigDecimal bd) {<a name="line.204"></a>
<FONT color="green">205</FONT>        BigDecimal cur = bd.stripTrailingZeros();<a name="line.205"></a>
<FONT color="green">206</FONT>        StringBuilder sb = new StringBuilder();<a name="line.206"></a>
<FONT color="green">207</FONT>    <a name="line.207"></a>
<FONT color="green">208</FONT>        for (int numConverted = 0; numConverted &lt; MAX_CHARS; numConverted++) {<a name="line.208"></a>
<FONT color="green">209</FONT>          cur = cur.multiply(ONE_PLACE);<a name="line.209"></a>
<FONT color="green">210</FONT>          int curCodePoint = cur.intValue();<a name="line.210"></a>
<FONT color="green">211</FONT>          if (0 == curCodePoint) {<a name="line.211"></a>
<FONT color="green">212</FONT>            break;<a name="line.212"></a>
<FONT color="green">213</FONT>          }<a name="line.213"></a>
<FONT color="green">214</FONT>    <a name="line.214"></a>
<FONT color="green">215</FONT>          cur = cur.subtract(new BigDecimal(curCodePoint));<a name="line.215"></a>
<FONT color="green">216</FONT>          sb.append(Character.toChars(curCodePoint));<a name="line.216"></a>
<FONT color="green">217</FONT>        }<a name="line.217"></a>
<FONT color="green">218</FONT>    <a name="line.218"></a>
<FONT color="green">219</FONT>        return sb.toString();<a name="line.219"></a>
<FONT color="green">220</FONT>      }<a name="line.220"></a>
<FONT color="green">221</FONT>    }<a name="line.221"></a>




























































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