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| <pre><span class="sourceLineNo">001</span>/**<a name="line.1"></a> |
| <span class="sourceLineNo">002</span> * Licensed to the Apache Software Foundation (ASF) under one<a name="line.2"></a> |
| <span class="sourceLineNo">003</span> * or more contributor license agreements. See the NOTICE file<a name="line.3"></a> |
| <span class="sourceLineNo">004</span> * distributed with this work for additional information<a name="line.4"></a> |
| <span class="sourceLineNo">005</span> * regarding copyright ownership. The ASF licenses this file<a name="line.5"></a> |
| <span class="sourceLineNo">006</span> * to you under the Apache License, Version 2.0 (the<a name="line.6"></a> |
| <span class="sourceLineNo">007</span> * "License"); you may not use this file except in compliance<a name="line.7"></a> |
| <span class="sourceLineNo">008</span> * with the License. You may obtain a copy of the License at<a name="line.8"></a> |
| <span class="sourceLineNo">009</span> *<a name="line.9"></a> |
| <span class="sourceLineNo">010</span> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.10"></a> |
| <span class="sourceLineNo">011</span> *<a name="line.11"></a> |
| <span class="sourceLineNo">012</span> * Unless required by applicable law or agreed to in writing, software<a name="line.12"></a> |
| <span class="sourceLineNo">013</span> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.13"></a> |
| <span class="sourceLineNo">014</span> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.14"></a> |
| <span class="sourceLineNo">015</span> * See the License for the specific language governing permissions and<a name="line.15"></a> |
| <span class="sourceLineNo">016</span> * limitations under the License.<a name="line.16"></a> |
| <span class="sourceLineNo">017</span> */<a name="line.17"></a> |
| <span class="sourceLineNo">018</span>package org.apache.hadoop.hbase.client;<a name="line.18"></a> |
| <span class="sourceLineNo">019</span><a name="line.19"></a> |
| <span class="sourceLineNo">020</span>import java.util.Optional;<a name="line.20"></a> |
| <span class="sourceLineNo">021</span><a name="line.21"></a> |
| <span class="sourceLineNo">022</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.22"></a> |
| <span class="sourceLineNo">023</span><a name="line.23"></a> |
| <span class="sourceLineNo">024</span>/**<a name="line.24"></a> |
| <span class="sourceLineNo">025</span> * This is the low level API for asynchronous scan.<a name="line.25"></a> |
| <span class="sourceLineNo">026</span> * <p><a name="line.26"></a> |
| <span class="sourceLineNo">027</span> * All results that match the given scan object will be passed to this class by calling<a name="line.27"></a> |
| <span class="sourceLineNo">028</span> * {@link #onNext(Result[], ScanController)}. {@link #onComplete()} means the scan is finished, and<a name="line.28"></a> |
| <span class="sourceLineNo">029</span> * {@link #onError(Throwable)} means we hit an unrecoverable error and the scan is terminated.<a name="line.29"></a> |
| <span class="sourceLineNo">030</span> * {@link #onHeartbeat(ScanController)} means the RS is still working but we can not get a valid<a name="line.30"></a> |
| <span class="sourceLineNo">031</span> * result to call {@link #onNext(Result[], ScanController)}. This is usually because the matched<a name="line.31"></a> |
| <span class="sourceLineNo">032</span> * results are too sparse, for example, a filter which almost filters out everything is specified.<a name="line.32"></a> |
| <span class="sourceLineNo">033</span> * <p><a name="line.33"></a> |
| <span class="sourceLineNo">034</span> * Notice that, all the methods here will be called directly in the thread which we send request to<a name="line.34"></a> |
| <span class="sourceLineNo">035</span> * HBase service. So if you want the asynchronous scanner fetch data from HBase in background while<a name="line.35"></a> |
| <span class="sourceLineNo">036</span> * you process the returned data, you need to move the processing work to another thread to make the<a name="line.36"></a> |
| <span class="sourceLineNo">037</span> * {@link #onNext(Result[], ScanController)} call return immediately. And please do NOT do any time<a name="line.37"></a> |
| <span class="sourceLineNo">038</span> * consuming tasks in these methods unless you know what you are doing.<a name="line.38"></a> |
| <span class="sourceLineNo">039</span> * @since 2.0.0<a name="line.39"></a> |
| <span class="sourceLineNo">040</span> */<a name="line.40"></a> |
| <span class="sourceLineNo">041</span>@InterfaceAudience.Public<a name="line.41"></a> |
| <span class="sourceLineNo">042</span>public interface AdvancedScanResultConsumer extends ScanResultConsumerBase {<a name="line.42"></a> |
| <span class="sourceLineNo">043</span><a name="line.43"></a> |
| <span class="sourceLineNo">044</span> /**<a name="line.44"></a> |
| <span class="sourceLineNo">045</span> * Used to resume a scan.<a name="line.45"></a> |
| <span class="sourceLineNo">046</span> */<a name="line.46"></a> |
| <span class="sourceLineNo">047</span> @InterfaceAudience.Public<a name="line.47"></a> |
| <span class="sourceLineNo">048</span> interface ScanResumer {<a name="line.48"></a> |
| <span class="sourceLineNo">049</span><a name="line.49"></a> |
| <span class="sourceLineNo">050</span> /**<a name="line.50"></a> |
| <span class="sourceLineNo">051</span> * Resume the scan. You are free to call it multiple time but only the first call will take<a name="line.51"></a> |
| <span class="sourceLineNo">052</span> * effect.<a name="line.52"></a> |
| <span class="sourceLineNo">053</span> */<a name="line.53"></a> |
| <span class="sourceLineNo">054</span> void resume();<a name="line.54"></a> |
| <span class="sourceLineNo">055</span> }<a name="line.55"></a> |
| <span class="sourceLineNo">056</span><a name="line.56"></a> |
| <span class="sourceLineNo">057</span> /**<a name="line.57"></a> |
| <span class="sourceLineNo">058</span> * Used to suspend or stop a scan, or get a scan cursor if available.<a name="line.58"></a> |
| <span class="sourceLineNo">059</span> * <p><a name="line.59"></a> |
| <span class="sourceLineNo">060</span> * Notice that, you should only call the {@link #suspend()} or {@link #terminate()} inside onNext<a name="line.60"></a> |
| <span class="sourceLineNo">061</span> * or onHeartbeat method. A IllegalStateException will be thrown if you call them at other places.<a name="line.61"></a> |
| <span class="sourceLineNo">062</span> * <p><a name="line.62"></a> |
| <span class="sourceLineNo">063</span> * You can only call one of the {@link #suspend()} and {@link #terminate()} methods(of course you<a name="line.63"></a> |
| <span class="sourceLineNo">064</span> * are free to not call them both), and the methods are not reentrant. An IllegalStateException<a name="line.64"></a> |
| <span class="sourceLineNo">065</span> * will be thrown if you have already called one of the methods.<a name="line.65"></a> |
| <span class="sourceLineNo">066</span> */<a name="line.66"></a> |
| <span class="sourceLineNo">067</span> @InterfaceAudience.Public<a name="line.67"></a> |
| <span class="sourceLineNo">068</span> interface ScanController {<a name="line.68"></a> |
| <span class="sourceLineNo">069</span><a name="line.69"></a> |
| <span class="sourceLineNo">070</span> /**<a name="line.70"></a> |
| <span class="sourceLineNo">071</span> * Suspend the scan.<a name="line.71"></a> |
| <span class="sourceLineNo">072</span> * <p><a name="line.72"></a> |
| <span class="sourceLineNo">073</span> * This means we will stop fetching data in background, i.e., will not call onNext any more<a name="line.73"></a> |
| <span class="sourceLineNo">074</span> * before you resume the scan.<a name="line.74"></a> |
| <span class="sourceLineNo">075</span> * @return A resumer used to resume the scan later.<a name="line.75"></a> |
| <span class="sourceLineNo">076</span> */<a name="line.76"></a> |
| <span class="sourceLineNo">077</span> ScanResumer suspend();<a name="line.77"></a> |
| <span class="sourceLineNo">078</span><a name="line.78"></a> |
| <span class="sourceLineNo">079</span> /**<a name="line.79"></a> |
| <span class="sourceLineNo">080</span> * Terminate the scan.<a name="line.80"></a> |
| <span class="sourceLineNo">081</span> * <p><a name="line.81"></a> |
| <span class="sourceLineNo">082</span> * This is useful when you have got enough results and want to stop the scan in onNext method,<a name="line.82"></a> |
| <span class="sourceLineNo">083</span> * or you want to stop the scan in onHeartbeat method because it has spent too many time.<a name="line.83"></a> |
| <span class="sourceLineNo">084</span> */<a name="line.84"></a> |
| <span class="sourceLineNo">085</span> void terminate();<a name="line.85"></a> |
| <span class="sourceLineNo">086</span><a name="line.86"></a> |
| <span class="sourceLineNo">087</span> /**<a name="line.87"></a> |
| <span class="sourceLineNo">088</span> * Get the scan cursor if available.<a name="line.88"></a> |
| <span class="sourceLineNo">089</span> * @return The scan cursor.<a name="line.89"></a> |
| <span class="sourceLineNo">090</span> */<a name="line.90"></a> |
| <span class="sourceLineNo">091</span> Optional<Cursor> cursor();<a name="line.91"></a> |
| <span class="sourceLineNo">092</span> }<a name="line.92"></a> |
| <span class="sourceLineNo">093</span><a name="line.93"></a> |
| <span class="sourceLineNo">094</span> /**<a name="line.94"></a> |
| <span class="sourceLineNo">095</span> * Indicate that we have receive some data.<a name="line.95"></a> |
| <span class="sourceLineNo">096</span> * @param results the data fetched from HBase service.<a name="line.96"></a> |
| <span class="sourceLineNo">097</span> * @param controller used to suspend or terminate the scan. Notice that the {@code controller}<a name="line.97"></a> |
| <span class="sourceLineNo">098</span> * instance is only valid within scope of onNext method. You can only call its method in<a name="line.98"></a> |
| <span class="sourceLineNo">099</span> * onNext, do NOT store it and call it later outside onNext.<a name="line.99"></a> |
| <span class="sourceLineNo">100</span> */<a name="line.100"></a> |
| <span class="sourceLineNo">101</span> void onNext(Result[] results, ScanController controller);<a name="line.101"></a> |
| <span class="sourceLineNo">102</span><a name="line.102"></a> |
| <span class="sourceLineNo">103</span> /**<a name="line.103"></a> |
| <span class="sourceLineNo">104</span> * Indicate that there is a heartbeat message but we have not cumulated enough cells to call<a name="line.104"></a> |
| <span class="sourceLineNo">105</span> * {@link #onNext(Result[], ScanController)}.<a name="line.105"></a> |
| <span class="sourceLineNo">106</span> * <p><a name="line.106"></a> |
| <span class="sourceLineNo">107</span> * Note that this method will always be called when RS returns something to us but we do not have<a name="line.107"></a> |
| <span class="sourceLineNo">108</span> * enough cells to call {@link #onNext(Result[], ScanController)}. Sometimes it may not be a<a name="line.108"></a> |
| <span class="sourceLineNo">109</span> * 'heartbeat' message for RS, for example, we have a large row with many cells and size limit is<a name="line.109"></a> |
| <span class="sourceLineNo">110</span> * exceeded before sending all the cells for this row. For RS it does send some data to us and the<a name="line.110"></a> |
| <span class="sourceLineNo">111</span> * time limit has not been reached, but we can not return the data to client so here we call this<a name="line.111"></a> |
| <span class="sourceLineNo">112</span> * method to tell client we have already received something.<a name="line.112"></a> |
| <span class="sourceLineNo">113</span> * <p><a name="line.113"></a> |
| <span class="sourceLineNo">114</span> * This method give you a chance to terminate a slow scan operation.<a name="line.114"></a> |
| <span class="sourceLineNo">115</span> * @param controller used to suspend or terminate the scan. Notice that the {@code controller}<a name="line.115"></a> |
| <span class="sourceLineNo">116</span> * instance is only valid within the scope of onHeartbeat method. You can only call its<a name="line.116"></a> |
| <span class="sourceLineNo">117</span> * method in onHeartbeat, do NOT store it and call it later outside onHeartbeat.<a name="line.117"></a> |
| <span class="sourceLineNo">118</span> */<a name="line.118"></a> |
| <span class="sourceLineNo">119</span> default void onHeartbeat(ScanController controller) {<a name="line.119"></a> |
| <span class="sourceLineNo">120</span> }<a name="line.120"></a> |
| <span class="sourceLineNo">121</span>}<a name="line.121"></a> |
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