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| <pre><span class="source-line-no">001</span><span id="line-1">/*</span> |
| <span class="source-line-no">002</span><span id="line-2"> * Licensed to the Apache Software Foundation (ASF) under one</span> |
| <span class="source-line-no">003</span><span id="line-3"> * or more contributor license agreements. See the NOTICE file</span> |
| <span class="source-line-no">004</span><span id="line-4"> * distributed with this work for additional information</span> |
| <span class="source-line-no">005</span><span id="line-5"> * regarding copyright ownership. The ASF licenses this file</span> |
| <span class="source-line-no">006</span><span id="line-6"> * to you under the Apache License, Version 2.0 (the</span> |
| <span class="source-line-no">007</span><span id="line-7"> * "License"); you may not use this file except in compliance</span> |
| <span class="source-line-no">008</span><span id="line-8"> * with the License. You may obtain a copy of the License at</span> |
| <span class="source-line-no">009</span><span id="line-9"> *</span> |
| <span class="source-line-no">010</span><span id="line-10"> * http://www.apache.org/licenses/LICENSE-2.0</span> |
| <span class="source-line-no">011</span><span id="line-11"> *</span> |
| <span class="source-line-no">012</span><span id="line-12"> * Unless required by applicable law or agreed to in writing, software</span> |
| <span class="source-line-no">013</span><span id="line-13"> * distributed under the License is distributed on an "AS IS" BASIS,</span> |
| <span class="source-line-no">014</span><span id="line-14"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span> |
| <span class="source-line-no">015</span><span id="line-15"> * See the License for the specific language governing permissions and</span> |
| <span class="source-line-no">016</span><span id="line-16"> * limitations under the License.</span> |
| <span class="source-line-no">017</span><span id="line-17"> */</span> |
| <span class="source-line-no">018</span><span id="line-18">package org.apache.hadoop.hbase.coprocessor;</span> |
| <span class="source-line-no">019</span><span id="line-19"></span> |
| <span class="source-line-no">020</span><span id="line-20">import java.io.IOException;</span> |
| <span class="source-line-no">021</span><span id="line-21">import org.apache.hadoop.hbase.Cell;</span> |
| <span class="source-line-no">022</span><span id="line-22">import org.apache.hadoop.hbase.HBaseInterfaceAudience;</span> |
| <span class="source-line-no">023</span><span id="line-23">import org.apache.yetus.audience.InterfaceAudience;</span> |
| <span class="source-line-no">024</span><span id="line-24">import org.apache.yetus.audience.InterfaceStability;</span> |
| <span class="source-line-no">025</span><span id="line-25"></span> |
| <span class="source-line-no">026</span><span id="line-26">import org.apache.hbase.thirdparty.com.google.protobuf.Message;</span> |
| <span class="source-line-no">027</span><span id="line-27"></span> |
| <span class="source-line-no">028</span><span id="line-28">/**</span> |
| <span class="source-line-no">029</span><span id="line-29"> * Defines how value for specific column is interpreted and provides utility methods like compare,</span> |
| <span class="source-line-no">030</span><span id="line-30"> * add, multiply etc for them. Takes column family, column qualifier and return the cell value. Its</span> |
| <span class="source-line-no">031</span><span id="line-31"> * concrete implementation should handle null case gracefully. Refer to</span> |
| <span class="source-line-no">032</span><span id="line-32"> * {@link org.apache.hadoop.hbase.client.coprocessor.LongColumnInterpreter} for an example.</span> |
| <span class="source-line-no">033</span><span id="line-33"> * <p></span> |
| <span class="source-line-no">034</span><span id="line-34"> * Takes two generic parameters and three Message parameters. The cell value type of the interpreter</span> |
| <span class="source-line-no">035</span><span id="line-35"> * is &lt;T&gt;. During some computations like sum, average, the return type can be different than</span> |
| <span class="source-line-no">036</span><span id="line-36"> * the cell value data type, for eg, sum of int cell values might overflow in case of a int result,</span> |
| <span class="source-line-no">037</span><span id="line-37"> * we should use Long for its result. Therefore, this class mandates to use a different (promoted)</span> |
| <span class="source-line-no">038</span><span id="line-38"> * data type for result of these computations &lt;S&gt;. All computations are performed on the</span> |
| <span class="source-line-no">039</span><span id="line-39"> * promoted data type &lt;S&gt;. There is a conversion method</span> |
| <span class="source-line-no">040</span><span id="line-40"> * {@link ColumnInterpreter#castToReturnType(Object)} which takes a &lt;T&gt; type and returns a</span> |
| <span class="source-line-no">041</span><span id="line-41"> * &lt;S&gt; type. The AggregateIm&gt;lementation uses PB messages to initialize the user's</span> |
| <span class="source-line-no">042</span><span id="line-42"> * ColumnInterpreter implementation, and for sending the responses back to AggregationClient.</span> |
| <span class="source-line-no">043</span><span id="line-43"> * <p></span> |
| <span class="source-line-no">044</span><span id="line-44"> * &lt;T&gt; Cell value data type<br></span> |
| <span class="source-line-no">045</span><span id="line-45"> * &lt;S&gt; Promoted data type<br></span> |
| <span class="source-line-no">046</span><span id="line-46"> * &lt;P&gt; PB message that is used to transport initializer specific bytes<br></span> |
| <span class="source-line-no">047</span><span id="line-47"> * &lt;Q&gt; PB message that is used to transport Cell (&lt;T&gt;) instance<br></span> |
| <span class="source-line-no">048</span><span id="line-48"> * &lt;R&gt; PB message that is used to transport Promoted (&lt;S&gt;) instance</span> |
| <span class="source-line-no">049</span><span id="line-49"> */</span> |
| <span class="source-line-no">050</span><span id="line-50">@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC)</span> |
| <span class="source-line-no">051</span><span id="line-51">@InterfaceStability.Evolving</span> |
| <span class="source-line-no">052</span><span id="line-52">public abstract class ColumnInterpreter<T, S, P extends Message, Q extends Message,</span> |
| <span class="source-line-no">053</span><span id="line-53"> R extends Message> {</span> |
| <span class="source-line-no">054</span><span id="line-54"></span> |
| <span class="source-line-no">055</span><span id="line-55"> /** Returns value of type T */</span> |
| <span class="source-line-no">056</span><span id="line-56"> public abstract T getValue(byte[] colFamily, byte[] colQualifier, Cell c) throws IOException;</span> |
| <span class="source-line-no">057</span><span id="line-57"></span> |
| <span class="source-line-no">058</span><span id="line-58"> /** Returns sum or non null value among (if either of them is null); otherwise returns a null. */</span> |
| <span class="source-line-no">059</span><span id="line-59"> public abstract S add(S l1, S l2);</span> |
| <span class="source-line-no">060</span><span id="line-60"></span> |
| <span class="source-line-no">061</span><span id="line-61"> /**</span> |
| <span class="source-line-no">062</span><span id="line-62"> * returns the maximum value for this type T</span> |
| <span class="source-line-no">063</span><span id="line-63"> */</span> |
| <span class="source-line-no">064</span><span id="line-64"> public abstract T getMaxValue();</span> |
| <span class="source-line-no">065</span><span id="line-65"></span> |
| <span class="source-line-no">066</span><span id="line-66"> public abstract T getMinValue();</span> |
| <span class="source-line-no">067</span><span id="line-67"></span> |
| <span class="source-line-no">068</span><span id="line-68"> /** Returns multiplication */</span> |
| <span class="source-line-no">069</span><span id="line-69"> public abstract S multiply(S o1, S o2);</span> |
| <span class="source-line-no">070</span><span id="line-70"></span> |
| <span class="source-line-no">071</span><span id="line-71"> /** Returns increment */</span> |
| <span class="source-line-no">072</span><span id="line-72"> public abstract S increment(S o);</span> |
| <span class="source-line-no">073</span><span id="line-73"></span> |
| <span class="source-line-no">074</span><span id="line-74"> /**</span> |
| <span class="source-line-no">075</span><span id="line-75"> * provides casting opportunity between the data types.</span> |
| <span class="source-line-no">076</span><span id="line-76"> */</span> |
| <span class="source-line-no">077</span><span id="line-77"> public abstract S castToReturnType(T o);</span> |
| <span class="source-line-no">078</span><span id="line-78"></span> |
| <span class="source-line-no">079</span><span id="line-79"> /**</span> |
| <span class="source-line-no">080</span><span id="line-80"> * This takes care if either of arguments are null. returns 0 if they are equal or both are null;</span> |
| <span class="source-line-no">081</span><span id="line-81"> * <ul></span> |
| <span class="source-line-no">082</span><span id="line-82"> * <li>&gt; 0 if l1 &gt; l2 or l1 is not null and l2 is null.</li></span> |
| <span class="source-line-no">083</span><span id="line-83"> * <li>&lt; 0 if l1 &lt; l2 or l1 is null and l2 is not null.</li></span> |
| <span class="source-line-no">084</span><span id="line-84"> * </ul></span> |
| <span class="source-line-no">085</span><span id="line-85"> */</span> |
| <span class="source-line-no">086</span><span id="line-86"> public abstract int compare(final T l1, final T l2);</span> |
| <span class="source-line-no">087</span><span id="line-87"></span> |
| <span class="source-line-no">088</span><span id="line-88"> /**</span> |
| <span class="source-line-no">089</span><span id="line-89"> * used for computing average of &lt;S&gt; data values. Not providing the divide method that takes</span> |
| <span class="source-line-no">090</span><span id="line-90"> * two &lt;S&gt; values as it is not needed as of now.</span> |
| <span class="source-line-no">091</span><span id="line-91"> */</span> |
| <span class="source-line-no">092</span><span id="line-92"> public abstract double divideForAvg(S o, Long l);</span> |
| <span class="source-line-no">093</span><span id="line-93"></span> |
| <span class="source-line-no">094</span><span id="line-94"> /**</span> |
| <span class="source-line-no">095</span><span id="line-95"> * This method should return any additional data that is needed on the server side to construct</span> |
| <span class="source-line-no">096</span><span id="line-96"> * the ColumnInterpreter. The server will pass this to the {@link #initialize} method. If there is</span> |
| <span class="source-line-no">097</span><span id="line-97"> * no ColumnInterpreter specific data (for e.g.,</span> |
| <span class="source-line-no">098</span><span id="line-98"> * {@link org.apache.hadoop.hbase.client.coprocessor.LongColumnInterpreter}) then null should be</span> |
| <span class="source-line-no">099</span><span id="line-99"> * returned.</span> |
| <span class="source-line-no">100</span><span id="line-100"> * @return the PB message</span> |
| <span class="source-line-no">101</span><span id="line-101"> */</span> |
| <span class="source-line-no">102</span><span id="line-102"> public abstract P getRequestData();</span> |
| <span class="source-line-no">103</span><span id="line-103"></span> |
| <span class="source-line-no">104</span><span id="line-104"> /**</span> |
| <span class="source-line-no">105</span><span id="line-105"> * This method should initialize any field(s) of the ColumnInterpreter with a parsing of the</span> |
| <span class="source-line-no">106</span><span id="line-106"> * passed message bytes (used on the server side).</span> |
| <span class="source-line-no">107</span><span id="line-107"> */</span> |
| <span class="source-line-no">108</span><span id="line-108"> public abstract void initialize(P msg);</span> |
| <span class="source-line-no">109</span><span id="line-109"></span> |
| <span class="source-line-no">110</span><span id="line-110"> /**</span> |
| <span class="source-line-no">111</span><span id="line-111"> * This method gets the PB message corresponding to the cell type</span> |
| <span class="source-line-no">112</span><span id="line-112"> * @return the PB message for the cell-type instance</span> |
| <span class="source-line-no">113</span><span id="line-113"> */</span> |
| <span class="source-line-no">114</span><span id="line-114"> public abstract Q getProtoForCellType(T t);</span> |
| <span class="source-line-no">115</span><span id="line-115"></span> |
| <span class="source-line-no">116</span><span id="line-116"> /**</span> |
| <span class="source-line-no">117</span><span id="line-117"> * This method gets the PB message corresponding to the cell type</span> |
| <span class="source-line-no">118</span><span id="line-118"> * @return the cell-type instance from the PB message</span> |
| <span class="source-line-no">119</span><span id="line-119"> */</span> |
| <span class="source-line-no">120</span><span id="line-120"> public abstract T getCellValueFromProto(Q q);</span> |
| <span class="source-line-no">121</span><span id="line-121"></span> |
| <span class="source-line-no">122</span><span id="line-122"> /**</span> |
| <span class="source-line-no">123</span><span id="line-123"> * This method gets the PB message corresponding to the promoted type</span> |
| <span class="source-line-no">124</span><span id="line-124"> * @return the PB message for the promoted-type instance</span> |
| <span class="source-line-no">125</span><span id="line-125"> */</span> |
| <span class="source-line-no">126</span><span id="line-126"> public abstract R getProtoForPromotedType(S s);</span> |
| <span class="source-line-no">127</span><span id="line-127"></span> |
| <span class="source-line-no">128</span><span id="line-128"> /**</span> |
| <span class="source-line-no">129</span><span id="line-129"> * This method gets the promoted type from the proto message</span> |
| <span class="source-line-no">130</span><span id="line-130"> * @return the promoted-type instance from the PB message</span> |
| <span class="source-line-no">131</span><span id="line-131"> */</span> |
| <span class="source-line-no">132</span><span id="line-132"> public abstract S getPromotedValueFromProto(R r);</span> |
| <span class="source-line-no">133</span><span id="line-133"></span> |
| <span class="source-line-no">134</span><span id="line-134"> /**</span> |
| <span class="source-line-no">135</span><span id="line-135"> * The response message comes as type S. This will convert/cast it to T. In some sense, performs</span> |
| <span class="source-line-no">136</span><span id="line-136"> * the opposite of {@link #castToReturnType(Object)}</span> |
| <span class="source-line-no">137</span><span id="line-137"> */</span> |
| <span class="source-line-no">138</span><span id="line-138"> public abstract T castToCellType(S response);</span> |
| <span class="source-line-no">139</span><span id="line-139">}</span> |
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| </pre> |
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