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<pre><span class="sourceLineNo">001</span>/*<a name="line.1"></a>
<span class="sourceLineNo">002</span> * Copyright (C) 2008-2013, fluid Operations AG<a name="line.2"></a>
<span class="sourceLineNo">003</span> *<a name="line.3"></a>
<span class="sourceLineNo">004</span> * FedX is free software: you can redistribute it and/or modify<a name="line.4"></a>
<span class="sourceLineNo">005</span> * it under the terms of the GNU Affero General Public License as<a name="line.5"></a>
<span class="sourceLineNo">006</span> * published by the Free Software Foundation, either version 3 of the<a name="line.6"></a>
<span class="sourceLineNo">007</span> * License, or (at your option) any later version.<a name="line.7"></a>
<span class="sourceLineNo">008</span> * <a name="line.8"></a>
<span class="sourceLineNo">009</span> * This program is distributed in the hope that it will be useful,<a name="line.9"></a>
<span class="sourceLineNo">010</span> * but WITHOUT ANY WARRANTY; without even the implied warranty of<a name="line.10"></a>
<span class="sourceLineNo">011</span> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the<a name="line.11"></a>
<span class="sourceLineNo">012</span> * GNU Affero General Public License for more details.<a name="line.12"></a>
<span class="sourceLineNo">013</span> * <a name="line.13"></a>
<span class="sourceLineNo">014</span> * You should have received a copy of the GNU Affero General Public License<a name="line.14"></a>
<span class="sourceLineNo">015</span> * along with this program.  If not, see &lt;http://www.gnu.org/licenses/&gt;.<a name="line.15"></a>
<span class="sourceLineNo">016</span> */<a name="line.16"></a>
<span class="sourceLineNo">017</span><a name="line.17"></a>
<span class="sourceLineNo">018</span>package com.fluidops.fedx.optimizer;<a name="line.18"></a>
<span class="sourceLineNo">019</span><a name="line.19"></a>
<span class="sourceLineNo">020</span>import java.util.ArrayList;<a name="line.20"></a>
<span class="sourceLineNo">021</span>import java.util.HashMap;<a name="line.21"></a>
<span class="sourceLineNo">022</span>import java.util.HashSet;<a name="line.22"></a>
<span class="sourceLineNo">023</span>import java.util.List;<a name="line.23"></a>
<span class="sourceLineNo">024</span>import java.util.Map;<a name="line.24"></a>
<span class="sourceLineNo">025</span>import java.util.Set;<a name="line.25"></a>
<span class="sourceLineNo">026</span><a name="line.26"></a>
<span class="sourceLineNo">027</span>import org.apache.log4j.Logger;<a name="line.27"></a>
<span class="sourceLineNo">028</span>import org.openrdf.query.algebra.ProjectionElem;<a name="line.28"></a>
<span class="sourceLineNo">029</span>import org.openrdf.query.algebra.QueryModelNode;<a name="line.29"></a>
<span class="sourceLineNo">030</span>import org.openrdf.query.algebra.Service;<a name="line.30"></a>
<span class="sourceLineNo">031</span>import org.openrdf.query.algebra.TupleExpr;<a name="line.31"></a>
<span class="sourceLineNo">032</span>import org.openrdf.query.algebra.Var;<a name="line.32"></a>
<span class="sourceLineNo">033</span>import org.openrdf.query.algebra.helpers.QueryModelVisitorBase;<a name="line.33"></a>
<span class="sourceLineNo">034</span><a name="line.34"></a>
<span class="sourceLineNo">035</span>import com.fluidops.fedx.algebra.NJoin;<a name="line.35"></a>
<span class="sourceLineNo">036</span>import com.fluidops.fedx.algebra.StatementTupleExpr;<a name="line.36"></a>
<span class="sourceLineNo">037</span>import com.fluidops.fedx.exception.OptimizationException;<a name="line.37"></a>
<span class="sourceLineNo">038</span>import com.fluidops.fedx.structures.QueryInfo;<a name="line.38"></a>
<span class="sourceLineNo">039</span><a name="line.39"></a>
<span class="sourceLineNo">040</span><a name="line.40"></a>
<span class="sourceLineNo">041</span>/**<a name="line.41"></a>
<span class="sourceLineNo">042</span> * Optimizer with the following tasks:<a name="line.42"></a>
<span class="sourceLineNo">043</span> * <a name="line.43"></a>
<span class="sourceLineNo">044</span> * 1. Find the scope of variables within groups (and store information <a name="line.44"></a>
<span class="sourceLineNo">045</span> *    within the node)<a name="line.45"></a>
<span class="sourceLineNo">046</span> * <a name="line.46"></a>
<span class="sourceLineNo">047</span> * <a name="line.47"></a>
<span class="sourceLineNo">048</span> * @author as<a name="line.48"></a>
<span class="sourceLineNo">049</span> */<a name="line.49"></a>
<span class="sourceLineNo">050</span>public class VariableScopeOptimizer extends QueryModelVisitorBase&lt;OptimizationException&gt; implements FedXOptimizer {<a name="line.50"></a>
<span class="sourceLineNo">051</span><a name="line.51"></a>
<span class="sourceLineNo">052</span>        public static Logger log = Logger.getLogger(VariableScopeOptimizer.class);<a name="line.52"></a>
<span class="sourceLineNo">053</span>        <a name="line.53"></a>
<span class="sourceLineNo">054</span>        protected final QueryInfo queryInfo;<a name="line.54"></a>
<span class="sourceLineNo">055</span>        protected final Set&lt;String&gt; globalVariables = new HashSet&lt;String&gt;();<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>        public VariableScopeOptimizer(QueryInfo queryInfo) {<a name="line.58"></a>
<span class="sourceLineNo">059</span>                super();<a name="line.59"></a>
<span class="sourceLineNo">060</span>                this.queryInfo = queryInfo;<a name="line.60"></a>
<span class="sourceLineNo">061</span>        }<a name="line.61"></a>
<span class="sourceLineNo">062</span><a name="line.62"></a>
<span class="sourceLineNo">063</span>        // TODO variables that are required in FILTER and OPTIONAL (i.e. outside of joins)<a name="line.63"></a>
<span class="sourceLineNo">064</span>        <a name="line.64"></a>
<span class="sourceLineNo">065</span><a name="line.65"></a>
<span class="sourceLineNo">066</span>        @Override<a name="line.66"></a>
<span class="sourceLineNo">067</span>        public void optimize(TupleExpr tupleExpr) {<a name="line.67"></a>
<span class="sourceLineNo">068</span>                tupleExpr.visit(this);<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>        @Override<a name="line.71"></a>
<span class="sourceLineNo">072</span>        public void meet(Service tupleExpr) {<a name="line.72"></a>
<span class="sourceLineNo">073</span>                // stop traversal<a name="line.73"></a>
<span class="sourceLineNo">074</span>        }<a name="line.74"></a>
<span class="sourceLineNo">075</span>                <a name="line.75"></a>
<span class="sourceLineNo">076</span>        <a name="line.76"></a>
<span class="sourceLineNo">077</span>        @Override<a name="line.77"></a>
<span class="sourceLineNo">078</span>        public void meet(ProjectionElem node) throws OptimizationException<a name="line.78"></a>
<span class="sourceLineNo">079</span>        {<a name="line.79"></a>
<span class="sourceLineNo">080</span>                globalVariables.add(node.getSourceName());<a name="line.80"></a>
<span class="sourceLineNo">081</span>                super.meet(node);<a name="line.81"></a>
<span class="sourceLineNo">082</span>        }<a name="line.82"></a>
<span class="sourceLineNo">083</span>        <a name="line.83"></a>
<span class="sourceLineNo">084</span>        public void meet(Var var) throws OptimizationException {<a name="line.84"></a>
<span class="sourceLineNo">085</span>                globalVariables.add(var.getName());<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>        @Override<a name="line.88"></a>
<span class="sourceLineNo">089</span>        public void meetOther(QueryModelNode node) {<a name="line.89"></a>
<span class="sourceLineNo">090</span>                if (node instanceof StatementTupleExpr) {<a name="line.90"></a>
<span class="sourceLineNo">091</span>                        meetTupleExpression((StatementTupleExpr)node);                  <a name="line.91"></a>
<span class="sourceLineNo">092</span>                } else if (node instanceof NJoin) {<a name="line.92"></a>
<span class="sourceLineNo">093</span>                        meetNJoin((NJoin) node);<a name="line.93"></a>
<span class="sourceLineNo">094</span>                } else {<a name="line.94"></a>
<span class="sourceLineNo">095</span>                        super.meetOther(node);<a name="line.95"></a>
<span class="sourceLineNo">096</span>                }<a name="line.96"></a>
<span class="sourceLineNo">097</span>        }<a name="line.97"></a>
<span class="sourceLineNo">098</span><a name="line.98"></a>
<span class="sourceLineNo">099</span>        <a name="line.99"></a>
<span class="sourceLineNo">100</span>        protected void meetTupleExpression(StatementTupleExpr node) {<a name="line.100"></a>
<span class="sourceLineNo">101</span>                <a name="line.101"></a>
<span class="sourceLineNo">102</span>                // we only get here if this expression is a toplevel expression,<a name="line.102"></a>
<span class="sourceLineNo">103</span>                // i.e. it is not part of a join<a name="line.103"></a>
<span class="sourceLineNo">104</span>                for (String var : node.getFreeVars())<a name="line.104"></a>
<span class="sourceLineNo">105</span>                        if (!isProjection(var))<a name="line.105"></a>
<span class="sourceLineNo">106</span>                                node.addLocalVar(var);<a name="line.106"></a>
<span class="sourceLineNo">107</span>        }<a name="line.107"></a>
<span class="sourceLineNo">108</span>        <a name="line.108"></a>
<span class="sourceLineNo">109</span>        protected void meetNJoin(NJoin node) {<a name="line.109"></a>
<span class="sourceLineNo">110</span><a name="line.110"></a>
<span class="sourceLineNo">111</span>                // map variable names to their parent expressions<a name="line.111"></a>
<span class="sourceLineNo">112</span>                Map&lt;String, List&lt;StatementTupleExpr&gt;&gt; map = new HashMap&lt;String, List&lt;StatementTupleExpr&gt;&gt;();<a name="line.112"></a>
<span class="sourceLineNo">113</span>                                <a name="line.113"></a>
<span class="sourceLineNo">114</span>                for (TupleExpr t : node.getArgs()) {<a name="line.114"></a>
<span class="sourceLineNo">115</span>                        <a name="line.115"></a>
<span class="sourceLineNo">116</span>                        // we can only deal with our expressions. In fact,<a name="line.116"></a>
<span class="sourceLineNo">117</span>                        // t should always be a StatementTupleExpr<a name="line.117"></a>
<span class="sourceLineNo">118</span>                        if (!(t instanceof StatementTupleExpr)) {<a name="line.118"></a>
<span class="sourceLineNo">119</span>                                log.warn("Encountered unexpected expressions type: " + t.getClass() + ", please report this.");<a name="line.119"></a>
<span class="sourceLineNo">120</span>                                return;<a name="line.120"></a>
<span class="sourceLineNo">121</span>                        }<a name="line.121"></a>
<span class="sourceLineNo">122</span>                        <a name="line.122"></a>
<span class="sourceLineNo">123</span>                        StatementTupleExpr st = (StatementTupleExpr)t;<a name="line.123"></a>
<span class="sourceLineNo">124</span>                        for (String var : st.getFreeVars()) {<a name="line.124"></a>
<span class="sourceLineNo">125</span>                                if (isProjection(var))<a name="line.125"></a>
<span class="sourceLineNo">126</span>                                        continue;<a name="line.126"></a>
<span class="sourceLineNo">127</span>                                List&lt;StatementTupleExpr&gt; l = map.get(var);<a name="line.127"></a>
<span class="sourceLineNo">128</span>                                if (l==null) {<a name="line.128"></a>
<span class="sourceLineNo">129</span>                                        l = new ArrayList&lt;StatementTupleExpr&gt;();<a name="line.129"></a>
<span class="sourceLineNo">130</span>                                        map.put(var, l);<a name="line.130"></a>
<span class="sourceLineNo">131</span>                                }<a name="line.131"></a>
<span class="sourceLineNo">132</span>                                l.add(st);<a name="line.132"></a>
<span class="sourceLineNo">133</span>                        }                       <a name="line.133"></a>
<span class="sourceLineNo">134</span>                }<a name="line.134"></a>
<span class="sourceLineNo">135</span>                <a name="line.135"></a>
<span class="sourceLineNo">136</span>                // register the local vars to the particular expression<a name="line.136"></a>
<span class="sourceLineNo">137</span>                for (Map.Entry&lt;String, List&lt;StatementTupleExpr&gt;&gt; e : map.entrySet()) {<a name="line.137"></a>
<span class="sourceLineNo">138</span>                        if (e.getValue().size()&gt;1)<a name="line.138"></a>
<span class="sourceLineNo">139</span>                                continue;<a name="line.139"></a>
<span class="sourceLineNo">140</span>                        StatementTupleExpr st = e.getValue().get(0);            <a name="line.140"></a>
<span class="sourceLineNo">141</span>                        st.addLocalVar(e.getKey());<a name="line.141"></a>
<span class="sourceLineNo">142</span>                }               <a name="line.142"></a>
<span class="sourceLineNo">143</span>        }       <a name="line.143"></a>
<span class="sourceLineNo">144</span>        <a name="line.144"></a>
<span class="sourceLineNo">145</span>        private boolean isProjection(String var) {<a name="line.145"></a>
<span class="sourceLineNo">146</span>                return globalVariables.contains(var);<a name="line.146"></a>
<span class="sourceLineNo">147</span>        }<a name="line.147"></a>
<span class="sourceLineNo">148</span>}<a name="line.148"></a>




























































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