<HTML>
<BODY BGCOLOR="white">
<PRE>
<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>    package org.apache.hadoop.mapreduce.lib.join;<a name="line.18"></a>
<FONT color="green">019</FONT>    <a name="line.19"></a>
<FONT color="green">020</FONT>    import java.io.IOException;<a name="line.20"></a>
<FONT color="green">021</FONT>    import java.util.ArrayList;<a name="line.21"></a>
<FONT color="green">022</FONT>    import java.util.Iterator;<a name="line.22"></a>
<FONT color="green">023</FONT>    <a name="line.23"></a>
<FONT color="green">024</FONT>    import org.apache.hadoop.classification.InterfaceAudience;<a name="line.24"></a>
<FONT color="green">025</FONT>    import org.apache.hadoop.classification.InterfaceStability;<a name="line.25"></a>
<FONT color="green">026</FONT>    import org.apache.hadoop.conf.Configuration;<a name="line.26"></a>
<FONT color="green">027</FONT>    import org.apache.hadoop.io.Writable;<a name="line.27"></a>
<FONT color="green">028</FONT>    import org.apache.hadoop.io.WritableUtils;<a name="line.28"></a>
<FONT color="green">029</FONT>    import org.apache.hadoop.util.ReflectionUtils;<a name="line.29"></a>
<FONT color="green">030</FONT>    <a name="line.30"></a>
<FONT color="green">031</FONT>    /**<a name="line.31"></a>
<FONT color="green">032</FONT>     * This class provides an implementation of ResetableIterator. The<a name="line.32"></a>
<FONT color="green">033</FONT>     * implementation uses an {@link java.util.ArrayList} to store elements<a name="line.33"></a>
<FONT color="green">034</FONT>     * added to it, replaying them as requested.<a name="line.34"></a>
<FONT color="green">035</FONT>     * Prefer {@link StreamBackedIterator}.<a name="line.35"></a>
<FONT color="green">036</FONT>     */<a name="line.36"></a>
<FONT color="green">037</FONT>    @InterfaceAudience.Public<a name="line.37"></a>
<FONT color="green">038</FONT>    @InterfaceStability.Stable<a name="line.38"></a>
<FONT color="green">039</FONT>    public class ArrayListBackedIterator&lt;X extends Writable&gt;<a name="line.39"></a>
<FONT color="green">040</FONT>        implements ResetableIterator&lt;X&gt; {<a name="line.40"></a>
<FONT color="green">041</FONT>    <a name="line.41"></a>
<FONT color="green">042</FONT>      private Iterator&lt;X&gt; iter;<a name="line.42"></a>
<FONT color="green">043</FONT>      private ArrayList&lt;X&gt; data;<a name="line.43"></a>
<FONT color="green">044</FONT>      private X hold = null;<a name="line.44"></a>
<FONT color="green">045</FONT>      private Configuration conf = new Configuration();<a name="line.45"></a>
<FONT color="green">046</FONT>    <a name="line.46"></a>
<FONT color="green">047</FONT>      public ArrayListBackedIterator() {<a name="line.47"></a>
<FONT color="green">048</FONT>        this(new ArrayList&lt;X&gt;());<a name="line.48"></a>
<FONT color="green">049</FONT>      }<a name="line.49"></a>
<FONT color="green">050</FONT>    <a name="line.50"></a>
<FONT color="green">051</FONT>      public ArrayListBackedIterator(ArrayList&lt;X&gt; data) {<a name="line.51"></a>
<FONT color="green">052</FONT>        this.data = data;<a name="line.52"></a>
<FONT color="green">053</FONT>        this.iter = this.data.iterator();<a name="line.53"></a>
<FONT color="green">054</FONT>      }<a name="line.54"></a>
<FONT color="green">055</FONT>    <a name="line.55"></a>
<FONT color="green">056</FONT>      public boolean hasNext() {<a name="line.56"></a>
<FONT color="green">057</FONT>        return iter.hasNext();<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>      public boolean next(X val) throws IOException {<a name="line.60"></a>
<FONT color="green">061</FONT>        if (iter.hasNext()) {<a name="line.61"></a>
<FONT color="green">062</FONT>          ReflectionUtils.copy(conf, iter.next(), val);<a name="line.62"></a>
<FONT color="green">063</FONT>          if (null == hold) {<a name="line.63"></a>
<FONT color="green">064</FONT>            hold = WritableUtils.clone(val, null);<a name="line.64"></a>
<FONT color="green">065</FONT>          } else {<a name="line.65"></a>
<FONT color="green">066</FONT>            ReflectionUtils.copy(conf, val, hold);<a name="line.66"></a>
<FONT color="green">067</FONT>          }<a name="line.67"></a>
<FONT color="green">068</FONT>          return true;<a name="line.68"></a>
<FONT color="green">069</FONT>        }<a name="line.69"></a>
<FONT color="green">070</FONT>        return false;<a name="line.70"></a>
<FONT color="green">071</FONT>      }<a name="line.71"></a>
<FONT color="green">072</FONT>    <a name="line.72"></a>
<FONT color="green">073</FONT>      public boolean replay(X val) throws IOException {<a name="line.73"></a>
<FONT color="green">074</FONT>        ReflectionUtils.copy(conf, hold, val);<a name="line.74"></a>
<FONT color="green">075</FONT>        return true;<a name="line.75"></a>
<FONT color="green">076</FONT>      }<a name="line.76"></a>
<FONT color="green">077</FONT>    <a name="line.77"></a>
<FONT color="green">078</FONT>      public void reset() {<a name="line.78"></a>
<FONT color="green">079</FONT>        iter = data.iterator();<a name="line.79"></a>
<FONT color="green">080</FONT>      }<a name="line.80"></a>
<FONT color="green">081</FONT>    <a name="line.81"></a>
<FONT color="green">082</FONT>      public void add(X item) throws IOException {<a name="line.82"></a>
<FONT color="green">083</FONT>        data.add(WritableUtils.clone(item, null));<a name="line.83"></a>
<FONT color="green">084</FONT>      }<a name="line.84"></a>
<FONT color="green">085</FONT>    <a name="line.85"></a>
<FONT color="green">086</FONT>      public void close() throws IOException {<a name="line.86"></a>
<FONT color="green">087</FONT>        iter = null;<a name="line.87"></a>
<FONT color="green">088</FONT>        data = null;<a name="line.88"></a>
<FONT color="green">089</FONT>      }<a name="line.89"></a>
<FONT color="green">090</FONT>    <a name="line.90"></a>
<FONT color="green">091</FONT>      public void clear() {<a name="line.91"></a>
<FONT color="green">092</FONT>        data.clear();<a name="line.92"></a>
<FONT color="green">093</FONT>        reset();<a name="line.93"></a>
<FONT color="green">094</FONT>      }<a name="line.94"></a>
<FONT color="green">095</FONT>    }<a name="line.95"></a>




























































</PRE>
</BODY>
</HTML>
