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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 info.aduna.iteration.CloseableIteration;<a name="line.20"></a>
<span class="sourceLineNo">021</span><a name="line.21"></a>
<span class="sourceLineNo">022</span>import java.util.ArrayList;<a name="line.22"></a>
<span class="sourceLineNo">023</span>import java.util.HashSet;<a name="line.23"></a>
<span class="sourceLineNo">024</span>import java.util.List;<a name="line.24"></a>
<span class="sourceLineNo">025</span>import java.util.Map;<a name="line.25"></a>
<span class="sourceLineNo">026</span>import java.util.Set;<a name="line.26"></a>
<span class="sourceLineNo">027</span>import java.util.concurrent.ConcurrentHashMap;<a name="line.27"></a>
<span class="sourceLineNo">028</span>import java.util.concurrent.CountDownLatch;<a name="line.28"></a>
<span class="sourceLineNo">029</span><a name="line.29"></a>
<span class="sourceLineNo">030</span>import org.apache.log4j.Logger;<a name="line.30"></a>
<span class="sourceLineNo">031</span>import org.openrdf.query.BindingSet;<a name="line.31"></a>
<span class="sourceLineNo">032</span>import org.openrdf.query.QueryEvaluationException;<a name="line.32"></a>
<span class="sourceLineNo">033</span>import org.openrdf.query.algebra.StatementPattern;<a name="line.33"></a>
<span class="sourceLineNo">034</span>import org.openrdf.query.impl.EmptyBindingSet;<a name="line.34"></a>
<span class="sourceLineNo">035</span>import org.openrdf.repository.RepositoryConnection;<a name="line.35"></a>
<span class="sourceLineNo">036</span><a name="line.36"></a>
<span class="sourceLineNo">037</span>import com.fluidops.fedx.EndpointManager;<a name="line.37"></a>
<span class="sourceLineNo">038</span>import com.fluidops.fedx.FederationManager;<a name="line.38"></a>
<span class="sourceLineNo">039</span>import com.fluidops.fedx.algebra.EmptyStatementPattern;<a name="line.39"></a>
<span class="sourceLineNo">040</span>import com.fluidops.fedx.algebra.ExclusiveStatement;<a name="line.40"></a>
<span class="sourceLineNo">041</span>import com.fluidops.fedx.algebra.StatementSource;<a name="line.41"></a>
<span class="sourceLineNo">042</span>import com.fluidops.fedx.algebra.StatementSource.StatementSourceType;<a name="line.42"></a>
<span class="sourceLineNo">043</span>import com.fluidops.fedx.algebra.StatementSourcePattern;<a name="line.43"></a>
<span class="sourceLineNo">044</span>import com.fluidops.fedx.cache.Cache;<a name="line.44"></a>
<span class="sourceLineNo">045</span>import com.fluidops.fedx.cache.Cache.StatementSourceAssurance;<a name="line.45"></a>
<span class="sourceLineNo">046</span>import com.fluidops.fedx.cache.CacheEntry;<a name="line.46"></a>
<span class="sourceLineNo">047</span>import com.fluidops.fedx.cache.CacheUtils;<a name="line.47"></a>
<span class="sourceLineNo">048</span>import com.fluidops.fedx.evaluation.TripleSource;<a name="line.48"></a>
<span class="sourceLineNo">049</span>import com.fluidops.fedx.evaluation.concurrent.ControlledWorkerScheduler;<a name="line.49"></a>
<span class="sourceLineNo">050</span>import com.fluidops.fedx.evaluation.concurrent.ParallelExecutor;<a name="line.50"></a>
<span class="sourceLineNo">051</span>import com.fluidops.fedx.evaluation.concurrent.ParallelTask;<a name="line.51"></a>
<span class="sourceLineNo">052</span>import com.fluidops.fedx.exception.ExceptionUtil;<a name="line.52"></a>
<span class="sourceLineNo">053</span>import com.fluidops.fedx.exception.OptimizationException;<a name="line.53"></a>
<span class="sourceLineNo">054</span>import com.fluidops.fedx.structures.Endpoint;<a name="line.54"></a>
<span class="sourceLineNo">055</span>import com.fluidops.fedx.structures.QueryInfo;<a name="line.55"></a>
<span class="sourceLineNo">056</span>import com.fluidops.fedx.structures.SubQuery;<a name="line.56"></a>
<span class="sourceLineNo">057</span>import com.fluidops.fedx.util.QueryStringUtil;<a name="line.57"></a>
<span class="sourceLineNo">058</span><a name="line.58"></a>
<span class="sourceLineNo">059</span><a name="line.59"></a>
<span class="sourceLineNo">060</span>/**<a name="line.60"></a>
<span class="sourceLineNo">061</span> * Perform source selection during optimization <a name="line.61"></a>
<span class="sourceLineNo">062</span> * <a name="line.62"></a>
<span class="sourceLineNo">063</span> * @author Andreas Schwarte<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>public class SourceSelection {<a name="line.66"></a>
<span class="sourceLineNo">067</span><a name="line.67"></a>
<span class="sourceLineNo">068</span>        public static Logger log = Logger.getLogger(SourceSelection.class);<a name="line.68"></a>
<span class="sourceLineNo">069</span>        <a name="line.69"></a>
<span class="sourceLineNo">070</span>        protected final List&lt;Endpoint&gt; endpoints;<a name="line.70"></a>
<span class="sourceLineNo">071</span>        protected final Cache cache;<a name="line.71"></a>
<span class="sourceLineNo">072</span>        protected final QueryInfo queryInfo;<a name="line.72"></a>
<span class="sourceLineNo">073</span>        <a name="line.73"></a>
<span class="sourceLineNo">074</span>        <a name="line.74"></a>
<span class="sourceLineNo">075</span>        public SourceSelection(List&lt;Endpoint&gt; endpoints, Cache cache, QueryInfo queryInfo) {<a name="line.75"></a>
<span class="sourceLineNo">076</span>                this.endpoints = endpoints;<a name="line.76"></a>
<span class="sourceLineNo">077</span>                this.cache = cache;<a name="line.77"></a>
<span class="sourceLineNo">078</span>                this.queryInfo = queryInfo;<a name="line.78"></a>
<span class="sourceLineNo">079</span>        }<a name="line.79"></a>
<span class="sourceLineNo">080</span><a name="line.80"></a>
<span class="sourceLineNo">081</span><a name="line.81"></a>
<span class="sourceLineNo">082</span>        /**<a name="line.82"></a>
<span class="sourceLineNo">083</span>         * Map statements to their sources. Use synchronized access!<a name="line.83"></a>
<span class="sourceLineNo">084</span>         */<a name="line.84"></a>
<span class="sourceLineNo">085</span>        protected Map&lt;StatementPattern, List&lt;StatementSource&gt;&gt; stmtToSources = new ConcurrentHashMap&lt;StatementPattern, List&lt;StatementSource&gt;&gt;();<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>        /**<a name="line.88"></a>
<span class="sourceLineNo">089</span>         * Perform source selection for the provided statements using cache or remote ASK queries.<a name="line.89"></a>
<span class="sourceLineNo">090</span>         * <a name="line.90"></a>
<span class="sourceLineNo">091</span>         * Remote ASK queries are evaluated in parallel using the concurrency infrastructure of FedX. Note,<a name="line.91"></a>
<span class="sourceLineNo">092</span>         * that this method is blocking until every source is resolved.<a name="line.92"></a>
<span class="sourceLineNo">093</span>         * <a name="line.93"></a>
<span class="sourceLineNo">094</span>         * The statement patterns are replaced by appropriate annotations in this optimization.<a name="line.94"></a>
<span class="sourceLineNo">095</span>         * <a name="line.95"></a>
<span class="sourceLineNo">096</span>         * @param stmts<a name="line.96"></a>
<span class="sourceLineNo">097</span>         */<a name="line.97"></a>
<span class="sourceLineNo">098</span>        public void doSourceSelection(List&lt;StatementPattern&gt; stmts) {<a name="line.98"></a>
<span class="sourceLineNo">099</span>                <a name="line.99"></a>
<span class="sourceLineNo">100</span>                List&lt;CheckTaskPair&gt; remoteCheckTasks = new ArrayList&lt;CheckTaskPair&gt;();<a name="line.100"></a>
<span class="sourceLineNo">101</span>                <a name="line.101"></a>
<span class="sourceLineNo">102</span>                // for each statement determine the relevant sources<a name="line.102"></a>
<span class="sourceLineNo">103</span>                for (StatementPattern stmt : stmts) {<a name="line.103"></a>
<span class="sourceLineNo">104</span>                        <a name="line.104"></a>
<span class="sourceLineNo">105</span>                        stmtToSources.put(stmt, new ArrayList&lt;StatementSource&gt;());<a name="line.105"></a>
<span class="sourceLineNo">106</span>                        <a name="line.106"></a>
<span class="sourceLineNo">107</span>                        SubQuery q = new SubQuery(stmt);<a name="line.107"></a>
<span class="sourceLineNo">108</span>                                <a name="line.108"></a>
<span class="sourceLineNo">109</span>                        // check for each current federation member (cache or remote ASK)<a name="line.109"></a>
<span class="sourceLineNo">110</span>                        for (Endpoint e : endpoints) {<a name="line.110"></a>
<span class="sourceLineNo">111</span>                                StatementSourceAssurance a = cache.canProvideStatements(q, e);<a name="line.111"></a>
<span class="sourceLineNo">112</span>                                if (a==StatementSourceAssurance.HAS_LOCAL_STATEMENTS) {<a name="line.112"></a>
<span class="sourceLineNo">113</span>                                        addSource(stmt, new StatementSource(e.getId(), StatementSourceType.LOCAL));<a name="line.113"></a>
<span class="sourceLineNo">114</span>                                } else if (a==StatementSourceAssurance.HAS_REMOTE_STATEMENTS) {<a name="line.114"></a>
<span class="sourceLineNo">115</span>                                        addSource(stmt, new StatementSource(e.getId(), StatementSourceType.REMOTE));                    <a name="line.115"></a>
<span class="sourceLineNo">116</span>                                } else if (a==StatementSourceAssurance.POSSIBLY_HAS_STATEMENTS) {                                       <a name="line.116"></a>
<span class="sourceLineNo">117</span>                                        remoteCheckTasks.add( new CheckTaskPair(e, stmt));<a name="line.117"></a>
<span class="sourceLineNo">118</span>                                }<a name="line.118"></a>
<span class="sourceLineNo">119</span>                        }<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>
<span class="sourceLineNo">122</span>                // if remote checks are necessary, execute them using the concurrency<a name="line.122"></a>
<span class="sourceLineNo">123</span>                // infrastructure and block until everything is resolved<a name="line.123"></a>
<span class="sourceLineNo">124</span>                if (remoteCheckTasks.size()&gt;0) {<a name="line.124"></a>
<span class="sourceLineNo">125</span>                        SourceSelectionExecutorWithLatch.run(this, remoteCheckTasks, cache);<a name="line.125"></a>
<span class="sourceLineNo">126</span>                }<a name="line.126"></a>
<span class="sourceLineNo">127</span>                                <a name="line.127"></a>
<span class="sourceLineNo">128</span>                for (StatementPattern stmt : stmtToSources.keySet()) {<a name="line.128"></a>
<span class="sourceLineNo">129</span>                        <a name="line.129"></a>
<span class="sourceLineNo">130</span>                        List&lt;StatementSource&gt; sources = stmtToSources.get(stmt);<a name="line.130"></a>
<span class="sourceLineNo">131</span>                        <a name="line.131"></a>
<span class="sourceLineNo">132</span>                        // if more than one source -&gt; StatementSourcePattern<a name="line.132"></a>
<span class="sourceLineNo">133</span>                        // exactly one source -&gt; OwnedStatementSourcePattern<a name="line.133"></a>
<span class="sourceLineNo">134</span>                        // otherwise: No resource seems to provide results<a name="line.134"></a>
<span class="sourceLineNo">135</span>                        <a name="line.135"></a>
<span class="sourceLineNo">136</span>                        if (sources.size()&gt;1) {<a name="line.136"></a>
<span class="sourceLineNo">137</span>                                StatementSourcePattern stmtNode = new StatementSourcePattern(stmt, queryInfo);<a name="line.137"></a>
<span class="sourceLineNo">138</span>                                for (StatementSource s : sources)<a name="line.138"></a>
<span class="sourceLineNo">139</span>                                        stmtNode.addStatementSource(s);<a name="line.139"></a>
<span class="sourceLineNo">140</span>                                stmt.replaceWith(stmtNode);<a name="line.140"></a>
<span class="sourceLineNo">141</span>                        }<a name="line.141"></a>
<span class="sourceLineNo">142</span>                <a name="line.142"></a>
<span class="sourceLineNo">143</span>                        else if (sources.size()==1) {<a name="line.143"></a>
<span class="sourceLineNo">144</span>                                stmt.replaceWith( new ExclusiveStatement(stmt, sources.get(0), queryInfo));<a name="line.144"></a>
<span class="sourceLineNo">145</span>                        }<a name="line.145"></a>
<span class="sourceLineNo">146</span>                        <a name="line.146"></a>
<span class="sourceLineNo">147</span>                        else {<a name="line.147"></a>
<span class="sourceLineNo">148</span>                                if (log.isDebugEnabled())<a name="line.148"></a>
<span class="sourceLineNo">149</span>                                        log.debug("Statement " + QueryStringUtil.toString(stmt) + " does not produce any results at the provided sources, replacing node with EmptyStatementPattern." );<a name="line.149"></a>
<span class="sourceLineNo">150</span>                                stmt.replaceWith( new EmptyStatementPattern(stmt));<a name="line.150"></a>
<span class="sourceLineNo">151</span>                        }<a name="line.151"></a>
<span class="sourceLineNo">152</span>                }               <a name="line.152"></a>
<span class="sourceLineNo">153</span>        }<a name="line.153"></a>
<span class="sourceLineNo">154</span>        <a name="line.154"></a>
<span class="sourceLineNo">155</span>        /**<a name="line.155"></a>
<span class="sourceLineNo">156</span>         * Retrieve a set of relevant sources for this query.<a name="line.156"></a>
<span class="sourceLineNo">157</span>         * @return<a name="line.157"></a>
<span class="sourceLineNo">158</span>         */<a name="line.158"></a>
<span class="sourceLineNo">159</span>        public Set&lt;Endpoint&gt; getRelevantSources() {<a name="line.159"></a>
<span class="sourceLineNo">160</span>                Set&lt;Endpoint&gt; endpoints = new HashSet&lt;Endpoint&gt;();<a name="line.160"></a>
<span class="sourceLineNo">161</span>                for (List&lt;StatementSource&gt; sourceList : stmtToSources.values())<a name="line.161"></a>
<span class="sourceLineNo">162</span>                        for (StatementSource source : sourceList)<a name="line.162"></a>
<span class="sourceLineNo">163</span>                                endpoints.add( EndpointManager.getEndpointManager().getEndpoint(source.getEndpointID()));<a name="line.163"></a>
<span class="sourceLineNo">164</span>                return endpoints;<a name="line.164"></a>
<span class="sourceLineNo">165</span>        }       <a name="line.165"></a>
<span class="sourceLineNo">166</span>        <a name="line.166"></a>
<span class="sourceLineNo">167</span>        /**<a name="line.167"></a>
<span class="sourceLineNo">168</span>         * Add a source to the given statement in the map (synchronized through map)<a name="line.168"></a>
<span class="sourceLineNo">169</span>         * <a name="line.169"></a>
<span class="sourceLineNo">170</span>         * @param stmt<a name="line.170"></a>
<span class="sourceLineNo">171</span>         * @param source<a name="line.171"></a>
<span class="sourceLineNo">172</span>         */<a name="line.172"></a>
<span class="sourceLineNo">173</span>        protected void addSource(StatementPattern stmt, StatementSource source) {<a name="line.173"></a>
<span class="sourceLineNo">174</span>                // The list for the stmt mapping is already initialized<a name="line.174"></a>
<span class="sourceLineNo">175</span>                List&lt;StatementSource&gt; sources = stmtToSources.get(stmt);<a name="line.175"></a>
<span class="sourceLineNo">176</span>                synchronized (sources) {<a name="line.176"></a>
<span class="sourceLineNo">177</span>                        sources.add(source);<a name="line.177"></a>
<span class="sourceLineNo">178</span>                }<a name="line.178"></a>
<span class="sourceLineNo">179</span>        }<a name="line.179"></a>
<span class="sourceLineNo">180</span>        <a name="line.180"></a>
<span class="sourceLineNo">181</span>        <a name="line.181"></a>
<span class="sourceLineNo">182</span>        <a name="line.182"></a>
<span class="sourceLineNo">183</span>        protected static class SourceSelectionExecutorWithLatch implements ParallelExecutor&lt;BindingSet&gt; {<a name="line.183"></a>
<span class="sourceLineNo">184</span>                <a name="line.184"></a>
<span class="sourceLineNo">185</span>                /**<a name="line.185"></a>
<span class="sourceLineNo">186</span>                 * Execute the given list of tasks in parallel, and block the thread until<a name="line.186"></a>
<span class="sourceLineNo">187</span>                 * all tasks are completed. Synchronization is achieved by means of a latch.<a name="line.187"></a>
<span class="sourceLineNo">188</span>                 * Results are added to the map of the source selection instance. Errors <a name="line.188"></a>
<span class="sourceLineNo">189</span>                 * are reported as {@link OptimizationException} instances.<a name="line.189"></a>
<span class="sourceLineNo">190</span>                 * <a name="line.190"></a>
<span class="sourceLineNo">191</span>                 * @param tasks<a name="line.191"></a>
<span class="sourceLineNo">192</span>                 */<a name="line.192"></a>
<span class="sourceLineNo">193</span>                public static void run(SourceSelection sourceSelection, List&lt;CheckTaskPair&gt; tasks, Cache cache) {<a name="line.193"></a>
<span class="sourceLineNo">194</span>                        new SourceSelectionExecutorWithLatch(sourceSelection).executeRemoteSourceSelection(tasks, cache);<a name="line.194"></a>
<span class="sourceLineNo">195</span>                }               <a name="line.195"></a>
<span class="sourceLineNo">196</span>                <a name="line.196"></a>
<span class="sourceLineNo">197</span>                private final SourceSelection sourceSelection;<a name="line.197"></a>
<span class="sourceLineNo">198</span>                private ControlledWorkerScheduler&lt;BindingSet&gt; scheduler = FederationManager.getInstance().getJoinScheduler();<a name="line.198"></a>
<span class="sourceLineNo">199</span>                private CountDownLatch latch;<a name="line.199"></a>
<span class="sourceLineNo">200</span>                private boolean finished=false;<a name="line.200"></a>
<span class="sourceLineNo">201</span>                private Thread initiatorThread;<a name="line.201"></a>
<span class="sourceLineNo">202</span>                protected List&lt;Exception&gt; errors = new ArrayList&lt;Exception&gt;();<a name="line.202"></a>
<span class="sourceLineNo">203</span>                <a name="line.203"></a>
<span class="sourceLineNo">204</span><a name="line.204"></a>
<span class="sourceLineNo">205</span>                private SourceSelectionExecutorWithLatch(SourceSelection sourceSelection) {<a name="line.205"></a>
<span class="sourceLineNo">206</span>                        this.sourceSelection = sourceSelection;<a name="line.206"></a>
<span class="sourceLineNo">207</span>                }<a name="line.207"></a>
<span class="sourceLineNo">208</span><a name="line.208"></a>
<span class="sourceLineNo">209</span>                /**<a name="line.209"></a>
<span class="sourceLineNo">210</span>                 * Execute the given list of tasks in parallel, and block the thread until<a name="line.210"></a>
<span class="sourceLineNo">211</span>                 * all tasks are completed. Synchronization is achieved by means of a latch<a name="line.211"></a>
<span class="sourceLineNo">212</span>                 * <a name="line.212"></a>
<span class="sourceLineNo">213</span>                 * @param tasks<a name="line.213"></a>
<span class="sourceLineNo">214</span>                 */<a name="line.214"></a>
<span class="sourceLineNo">215</span>                private void executeRemoteSourceSelection(List&lt;CheckTaskPair&gt; tasks, Cache cache) {<a name="line.215"></a>
<span class="sourceLineNo">216</span>                        if (tasks.size()==0)<a name="line.216"></a>
<span class="sourceLineNo">217</span>                                return;<a name="line.217"></a>
<span class="sourceLineNo">218</span>                        <a name="line.218"></a>
<span class="sourceLineNo">219</span>                        initiatorThread = Thread.currentThread();<a name="line.219"></a>
<span class="sourceLineNo">220</span>                        latch = new CountDownLatch(tasks.size());<a name="line.220"></a>
<span class="sourceLineNo">221</span>                        for (CheckTaskPair task : tasks)<a name="line.221"></a>
<span class="sourceLineNo">222</span>                                scheduler.schedule( new ParallelCheckTask(task.e, task.t, this) );<a name="line.222"></a>
<span class="sourceLineNo">223</span>                        <a name="line.223"></a>
<span class="sourceLineNo">224</span>                        try     {<a name="line.224"></a>
<span class="sourceLineNo">225</span>                                latch.await();  // TODO maybe add timeout here<a name="line.225"></a>
<span class="sourceLineNo">226</span>                        } catch (InterruptedException e) {<a name="line.226"></a>
<span class="sourceLineNo">227</span>                                log.debug("Error during source selection. Thread got interrupted.");<a name="line.227"></a>
<span class="sourceLineNo">228</span>                        }<a name="line.228"></a>
<span class="sourceLineNo">229</span><a name="line.229"></a>
<span class="sourceLineNo">230</span>                        finished = true;<a name="line.230"></a>
<span class="sourceLineNo">231</span>                        <a name="line.231"></a>
<span class="sourceLineNo">232</span>                        // check for errors:<a name="line.232"></a>
<span class="sourceLineNo">233</span>                        if (errors.size()&gt;0) {<a name="line.233"></a>
<span class="sourceLineNo">234</span>                                log.error(errors.size() + " errors were reported:");<a name="line.234"></a>
<span class="sourceLineNo">235</span>                                for (Exception e : errors)<a name="line.235"></a>
<span class="sourceLineNo">236</span>                                        log.error(ExceptionUtil.getExceptionString("Error occured", e));<a name="line.236"></a>
<span class="sourceLineNo">237</span>                                                                <a name="line.237"></a>
<span class="sourceLineNo">238</span>                                Exception ex = errors.get(0);<a name="line.238"></a>
<span class="sourceLineNo">239</span>                                errors.clear();<a name="line.239"></a>
<span class="sourceLineNo">240</span>                                if (ex instanceof OptimizationException)<a name="line.240"></a>
<span class="sourceLineNo">241</span>                                        throw (OptimizationException)ex;<a name="line.241"></a>
<span class="sourceLineNo">242</span>                                <a name="line.242"></a>
<span class="sourceLineNo">243</span>                                throw new OptimizationException(ex.getMessage(), ex);<a name="line.243"></a>
<span class="sourceLineNo">244</span>                        }<a name="line.244"></a>
<span class="sourceLineNo">245</span>                }<a name="line.245"></a>
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<span class="sourceLineNo">247</span>                @Override<a name="line.247"></a>
<span class="sourceLineNo">248</span>                public void run() { /* not needed */ }<a name="line.248"></a>
<span class="sourceLineNo">249</span><a name="line.249"></a>
<span class="sourceLineNo">250</span>                @Override<a name="line.250"></a>
<span class="sourceLineNo">251</span>                public void addResult(CloseableIteration&lt;BindingSet, QueryEvaluationException&gt; res)       {<a name="line.251"></a>
<span class="sourceLineNo">252</span>                        latch.countDown();<a name="line.252"></a>
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<span class="sourceLineNo">257</span>                        errors.add(e);<a name="line.257"></a>
<span class="sourceLineNo">258</span>                        scheduler.abort(getQueryId());  // abort all tasks belonging to this query id<a name="line.258"></a>
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<span class="sourceLineNo">260</span>                                initiatorThread.interrupt();<a name="line.260"></a>
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<span class="sourceLineNo">264</span>                public void done()      { /* not needed */ }<a name="line.264"></a>
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<span class="sourceLineNo">272</span>                public int getQueryId() {<a name="line.272"></a>
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<span class="sourceLineNo">276</span>        <a name="line.276"></a>
<span class="sourceLineNo">277</span>        <a name="line.277"></a>
<span class="sourceLineNo">278</span>        protected class CheckTaskPair {<a name="line.278"></a>
<span class="sourceLineNo">279</span>                public final Endpoint e;<a name="line.279"></a>
<span class="sourceLineNo">280</span>                public final StatementPattern t;<a name="line.280"></a>
<span class="sourceLineNo">281</span>                public CheckTaskPair(Endpoint e, StatementPattern t){<a name="line.281"></a>
<span class="sourceLineNo">282</span>                        this.e = e;<a name="line.282"></a>
<span class="sourceLineNo">283</span>                        this.t = t;<a name="line.283"></a>
<span class="sourceLineNo">284</span>                }               <a name="line.284"></a>
<span class="sourceLineNo">285</span>        }<a name="line.285"></a>
<span class="sourceLineNo">286</span>        <a name="line.286"></a>
<span class="sourceLineNo">287</span>        <a name="line.287"></a>
<span class="sourceLineNo">288</span>        /**<a name="line.288"></a>
<span class="sourceLineNo">289</span>         * Task for sending an ASK request to the endpoints (for source selection)<a name="line.289"></a>
<span class="sourceLineNo">290</span>         * <a name="line.290"></a>
<span class="sourceLineNo">291</span>         * @author Andreas Schwarte<a name="line.291"></a>
<span class="sourceLineNo">292</span>         */<a name="line.292"></a>
<span class="sourceLineNo">293</span>        protected static class ParallelCheckTask implements ParallelTask&lt;BindingSet&gt; {<a name="line.293"></a>
<span class="sourceLineNo">294</span><a name="line.294"></a>
<span class="sourceLineNo">295</span>                protected final Endpoint endpoint;<a name="line.295"></a>
<span class="sourceLineNo">296</span>                protected final StatementPattern stmt;<a name="line.296"></a>
<span class="sourceLineNo">297</span>                protected final SourceSelectionExecutorWithLatch control;<a name="line.297"></a>
<span class="sourceLineNo">298</span>                <a name="line.298"></a>
<span class="sourceLineNo">299</span>                public ParallelCheckTask(Endpoint endpoint, StatementPattern stmt, SourceSelectionExecutorWithLatch control) {<a name="line.299"></a>
<span class="sourceLineNo">300</span>                        this.endpoint = endpoint;<a name="line.300"></a>
<span class="sourceLineNo">301</span>                        this.stmt = stmt;<a name="line.301"></a>
<span class="sourceLineNo">302</span>                        this.control = control;<a name="line.302"></a>
<span class="sourceLineNo">303</span>                }<a name="line.303"></a>
<span class="sourceLineNo">304</span><a name="line.304"></a>
<span class="sourceLineNo">305</span>                <a name="line.305"></a>
<span class="sourceLineNo">306</span>                @Override<a name="line.306"></a>
<span class="sourceLineNo">307</span>                public CloseableIteration&lt;BindingSet, QueryEvaluationException&gt; performTask() throws Exception {<a name="line.307"></a>
<span class="sourceLineNo">308</span>                        try {<a name="line.308"></a>
<span class="sourceLineNo">309</span>                                TripleSource t = endpoint.getTripleSource();<a name="line.309"></a>
<span class="sourceLineNo">310</span>                                RepositoryConnection conn = endpoint.getConn(); <a name="line.310"></a>
<span class="sourceLineNo">311</span><a name="line.311"></a>
<span class="sourceLineNo">312</span>                                boolean hasResults = t.hasStatements(stmt, conn, EmptyBindingSet.getInstance());<a name="line.312"></a>
<span class="sourceLineNo">313</span><a name="line.313"></a>
<span class="sourceLineNo">314</span>                                SourceSelection sourceSelection = control.sourceSelection;<a name="line.314"></a>
<span class="sourceLineNo">315</span>                                CacheEntry entry = CacheUtils.createCacheEntry(endpoint, hasResults);<a name="line.315"></a>
<span class="sourceLineNo">316</span>                                sourceSelection.cache.updateEntry( new SubQuery(stmt), entry);<a name="line.316"></a>
<span class="sourceLineNo">317</span><a name="line.317"></a>
<span class="sourceLineNo">318</span>                                if (hasResults)<a name="line.318"></a>
<span class="sourceLineNo">319</span>                                        sourceSelection.addSource(stmt, new StatementSource(endpoint.getId(), StatementSourceType.REMOTE));<a name="line.319"></a>
<span class="sourceLineNo">320</span>                                <a name="line.320"></a>
<span class="sourceLineNo">321</span>                                return null;<a name="line.321"></a>
<span class="sourceLineNo">322</span>                        } catch (Exception e) {<a name="line.322"></a>
<span class="sourceLineNo">323</span>                                this.control.toss(e);<a name="line.323"></a>
<span class="sourceLineNo">324</span>                                throw new OptimizationException("Error checking results for endpoint " + endpoint.getId() + ": " + e.getMessage(), e);<a name="line.324"></a>
<span class="sourceLineNo">325</span>                        }<a name="line.325"></a>
<span class="sourceLineNo">326</span>                }<a name="line.326"></a>
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<span class="sourceLineNo">328</span>                @Override<a name="line.328"></a>
<span class="sourceLineNo">329</span>                public ParallelExecutor&lt;BindingSet&gt; getControl() {<a name="line.329"></a>
<span class="sourceLineNo">330</span>                        return control;<a name="line.330"></a>
<span class="sourceLineNo">331</span>                }               <a name="line.331"></a>
<span class="sourceLineNo">332</span>        }<a name="line.332"></a>
<span class="sourceLineNo">333</span>        <a name="line.333"></a>
<span class="sourceLineNo">334</span>                <a name="line.334"></a>
<span class="sourceLineNo">335</span>}<a name="line.335"></a>
<span class="sourceLineNo">336</span><a name="line.336"></a>
<span class="sourceLineNo">337</span><a name="line.337"></a>
<span class="sourceLineNo">338</span><a name="line.338"></a>
<span class="sourceLineNo">339</span><a name="line.339"></a>




























































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