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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.join;<a name="line.19"></a>
<FONT color="green">020</FONT>    <a name="line.20"></a>
<FONT color="green">021</FONT>    import java.io.IOException;<a name="line.21"></a>
<FONT color="green">022</FONT>    import java.util.ArrayList;<a name="line.22"></a>
<FONT color="green">023</FONT>    import java.util.PriorityQueue;<a name="line.23"></a>
<FONT color="green">024</FONT>    <a name="line.24"></a>
<FONT color="green">025</FONT>    import org.apache.hadoop.classification.InterfaceAudience;<a name="line.25"></a>
<FONT color="green">026</FONT>    import org.apache.hadoop.classification.InterfaceStability;<a name="line.26"></a>
<FONT color="green">027</FONT>    import org.apache.hadoop.conf.Configuration;<a name="line.27"></a>
<FONT color="green">028</FONT>    import org.apache.hadoop.io.NullWritable;<a name="line.28"></a>
<FONT color="green">029</FONT>    import org.apache.hadoop.io.Writable;<a name="line.29"></a>
<FONT color="green">030</FONT>    import org.apache.hadoop.io.WritableComparable;<a name="line.30"></a>
<FONT color="green">031</FONT>    import org.apache.hadoop.io.WritableComparator;<a name="line.31"></a>
<FONT color="green">032</FONT>    import org.apache.hadoop.util.ReflectionUtils;<a name="line.32"></a>
<FONT color="green">033</FONT>    <a name="line.33"></a>
<FONT color="green">034</FONT>    /**<a name="line.34"></a>
<FONT color="green">035</FONT>     * Prefer the &amp;quot;rightmost&amp;quot; data source for this key.<a name="line.35"></a>
<FONT color="green">036</FONT>     * For example, &lt;tt&gt;override(S1,S2,S3)&lt;/tt&gt; will prefer values<a name="line.36"></a>
<FONT color="green">037</FONT>     * from S3 over S2, and values from S2 over S1 for all keys<a name="line.37"></a>
<FONT color="green">038</FONT>     * emitted from all sources.<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.Stable<a name="line.41"></a>
<FONT color="green">042</FONT>    public class OverrideRecordReader&lt;K extends WritableComparable&lt;?&gt;,<a name="line.42"></a>
<FONT color="green">043</FONT>                                      V extends Writable&gt;<a name="line.43"></a>
<FONT color="green">044</FONT>        extends MultiFilterRecordReader&lt;K,V&gt; {<a name="line.44"></a>
<FONT color="green">045</FONT>    <a name="line.45"></a>
<FONT color="green">046</FONT>      OverrideRecordReader(int id, Configuration conf, int capacity,<a name="line.46"></a>
<FONT color="green">047</FONT>          Class&lt;? extends WritableComparator&gt; cmpcl) throws IOException {<a name="line.47"></a>
<FONT color="green">048</FONT>        super(id, conf, capacity, cmpcl);<a name="line.48"></a>
<FONT color="green">049</FONT>      }<a name="line.49"></a>
<FONT color="green">050</FONT>      private Class&lt;? extends Writable&gt; valueclass = null;<a name="line.50"></a>
<FONT color="green">051</FONT>    <a name="line.51"></a>
<FONT color="green">052</FONT>      /**<a name="line.52"></a>
<FONT color="green">053</FONT>       * Emit the value with the highest position in the tuple.<a name="line.53"></a>
<FONT color="green">054</FONT>       */<a name="line.54"></a>
<FONT color="green">055</FONT>      @SuppressWarnings("unchecked") // No static typeinfo on Tuples<a name="line.55"></a>
<FONT color="green">056</FONT>      protected V emit(TupleWritable dst) {<a name="line.56"></a>
<FONT color="green">057</FONT>        return (V) dst.iterator().next();<a name="line.57"></a>
<FONT color="green">058</FONT>      }<a name="line.58"></a>
<FONT color="green">059</FONT>    <a name="line.59"></a>
<FONT color="green">060</FONT>      @SuppressWarnings("unchecked") // Explicit check for value class agreement<a name="line.60"></a>
<FONT color="green">061</FONT>      public V createValue() {<a name="line.61"></a>
<FONT color="green">062</FONT>        if (null == valueclass) {<a name="line.62"></a>
<FONT color="green">063</FONT>          Class&lt;?&gt; cls = kids[kids.length -1].createValue().getClass();<a name="line.63"></a>
<FONT color="green">064</FONT>          for (int i = kids.length -1; cls.equals(NullWritable.class); i--) {<a name="line.64"></a>
<FONT color="green">065</FONT>            cls = kids[i].createValue().getClass();<a name="line.65"></a>
<FONT color="green">066</FONT>          }<a name="line.66"></a>
<FONT color="green">067</FONT>          valueclass = cls.asSubclass(Writable.class);<a name="line.67"></a>
<FONT color="green">068</FONT>        }<a name="line.68"></a>
<FONT color="green">069</FONT>        if (valueclass.equals(NullWritable.class)) {<a name="line.69"></a>
<FONT color="green">070</FONT>          return (V) NullWritable.get();<a name="line.70"></a>
<FONT color="green">071</FONT>        }<a name="line.71"></a>
<FONT color="green">072</FONT>        return (V) ReflectionUtils.newInstance(valueclass, null);<a name="line.72"></a>
<FONT color="green">073</FONT>      }<a name="line.73"></a>
<FONT color="green">074</FONT>    <a name="line.74"></a>
<FONT color="green">075</FONT>      /**<a name="line.75"></a>
<FONT color="green">076</FONT>       * Instead of filling the JoinCollector with iterators from all<a name="line.76"></a>
<FONT color="green">077</FONT>       * data sources, fill only the rightmost for this key.<a name="line.77"></a>
<FONT color="green">078</FONT>       * This not only saves space by discarding the other sources, but<a name="line.78"></a>
<FONT color="green">079</FONT>       * it also emits the number of key-value pairs in the preferred<a name="line.79"></a>
<FONT color="green">080</FONT>       * RecordReader instead of repeating that stream n times, where<a name="line.80"></a>
<FONT color="green">081</FONT>       * n is the cardinality of the cross product of the discarded<a name="line.81"></a>
<FONT color="green">082</FONT>       * streams for the given key.<a name="line.82"></a>
<FONT color="green">083</FONT>       */<a name="line.83"></a>
<FONT color="green">084</FONT>      protected void fillJoinCollector(K iterkey) <a name="line.84"></a>
<FONT color="green">085</FONT>          throws IOException, InterruptedException {<a name="line.85"></a>
<FONT color="green">086</FONT>        final PriorityQueue&lt;ComposableRecordReader&lt;K,?&gt;&gt; q = <a name="line.86"></a>
<FONT color="green">087</FONT>          getRecordReaderQueue();<a name="line.87"></a>
<FONT color="green">088</FONT>        if (q != null &amp;&amp; !q.isEmpty()) {<a name="line.88"></a>
<FONT color="green">089</FONT>          int highpos = -1;<a name="line.89"></a>
<FONT color="green">090</FONT>          ArrayList&lt;ComposableRecordReader&lt;K,?&gt;&gt; list =<a name="line.90"></a>
<FONT color="green">091</FONT>            new ArrayList&lt;ComposableRecordReader&lt;K,?&gt;&gt;(kids.length);<a name="line.91"></a>
<FONT color="green">092</FONT>          q.peek().key(iterkey);<a name="line.92"></a>
<FONT color="green">093</FONT>          final WritableComparator cmp = getComparator();<a name="line.93"></a>
<FONT color="green">094</FONT>          while (0 == cmp.compare(q.peek().key(), iterkey)) {<a name="line.94"></a>
<FONT color="green">095</FONT>            ComposableRecordReader&lt;K,?&gt; t = q.poll();<a name="line.95"></a>
<FONT color="green">096</FONT>            if (-1 == highpos || list.get(highpos).id() &lt; t.id()) {<a name="line.96"></a>
<FONT color="green">097</FONT>              highpos = list.size();<a name="line.97"></a>
<FONT color="green">098</FONT>            }<a name="line.98"></a>
<FONT color="green">099</FONT>            list.add(t);<a name="line.99"></a>
<FONT color="green">100</FONT>            if (q.isEmpty())<a name="line.100"></a>
<FONT color="green">101</FONT>              break;<a name="line.101"></a>
<FONT color="green">102</FONT>          }<a name="line.102"></a>
<FONT color="green">103</FONT>          ComposableRecordReader&lt;K,?&gt; t = list.remove(highpos);<a name="line.103"></a>
<FONT color="green">104</FONT>          t.accept(jc, iterkey);<a name="line.104"></a>
<FONT color="green">105</FONT>          for (ComposableRecordReader&lt;K,?&gt; rr : list) {<a name="line.105"></a>
<FONT color="green">106</FONT>            rr.skip(iterkey);<a name="line.106"></a>
<FONT color="green">107</FONT>          }<a name="line.107"></a>
<FONT color="green">108</FONT>          list.add(t);<a name="line.108"></a>
<FONT color="green">109</FONT>          for (ComposableRecordReader&lt;K,?&gt; rr : list) {<a name="line.109"></a>
<FONT color="green">110</FONT>            if (rr.hasNext()) {<a name="line.110"></a>
<FONT color="green">111</FONT>              q.add(rr);<a name="line.111"></a>
<FONT color="green">112</FONT>            }<a name="line.112"></a>
<FONT color="green">113</FONT>          }<a name="line.113"></a>
<FONT color="green">114</FONT>        }<a name="line.114"></a>
<FONT color="green">115</FONT>      }<a name="line.115"></a>
<FONT color="green">116</FONT>    <a name="line.116"></a>
<FONT color="green">117</FONT>    }<a name="line.117"></a>




























































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