[VIVO-1122] Fix to the way resources are consumed in the SPARQL clients, so that it doesn't leak / tie up HTTP connections.

webapp/src/edu/cornell/mannlib/vitro/webapp/dao/jena/SparqlGraph.java

@@ -7,6 +7,7 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
+import edu.cornell.mannlib.vitro.webapp.utils.http.HttpClientFactory;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.http.HttpResponse;
@@ -44,6 +45,7 @@ import com.hp.hpl.jena.util.iterator.SingletonIterator;
 import com.hp.hpl.jena.util.iterator.WrappedIterator;
 
 import edu.cornell.mannlib.vitro.webapp.utils.logging.ToString;
+import org.apache.http.util.EntityUtils;
 
 public class SparqlGraph implements GraphWithPerform {
     
@@ -73,9 +75,7 @@ public class SparqlGraph implements GraphWithPerform {
        this.endpointURI = endpointURI;
        this.graphURI = graphURI;
        
-       PoolingClientConnectionManager cm = new PoolingClientConnectionManager();
+       this.httpClient = HttpClientFactory.getHttpClient();
-       cm.setDefaultMaxPerRoute(50);
-       this.httpClient = new DefaultHttpClient(cm);
     }
     
     public String getEndpointURI() {
@@ -92,20 +92,26 @@ public class SparqlGraph implements GraphWithPerform {
     }
 
     public void executeUpdate(String updateString) {
-        try {
         HttpPost meth = new HttpPost(endpointURI);
+        try {
             meth.addHeader("Content-Type", "application/x-www-form-urlencoded");
             meth.setEntity(new UrlEncodedFormEntity(Arrays.asList(
                     new BasicNameValuePair("update", updateString))));
             HttpResponse response = httpClient.execute(meth);
+            try {
                 int statusCode = response.getStatusLine().getStatusCode();
                 if (statusCode > 399) {
                     log.error("response " + statusCode + " to update. \n");
                     throw new RuntimeException("Unable to perform SPARQL UPDATE: \n"
                             + updateString);
                 }
+            } finally {
+                EntityUtils.consume(response.getEntity());
+            }
         } catch (Exception e) {
             throw new RuntimeException("Unable to perform SPARQL UPDATE", e);
+        } finally {
+            meth.abort();
         }
     }
     

webapp/src/edu/cornell/mannlib/vitro/webapp/rdfservice/impl/sparql/RDFServiceSparql.java

@@ -16,10 +16,12 @@ import java.util.List;
 import java.util.concurrent.ConcurrentLinkedQueue;
 
 import edu.cornell.mannlib.vitro.webapp.rdfservice.ResultSetConsumer;
+import edu.cornell.mannlib.vitro.webapp.utils.http.HttpClientFactory;
 import org.apache.commons.io.IOUtils;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.http.HttpResponse;
+import org.apache.http.client.HttpClient;
 import org.apache.http.client.entity.UrlEncodedFormEntity;
 import org.apache.http.client.methods.HttpGet;
 import org.apache.http.client.methods.HttpPost;
@@ -27,6 +29,7 @@ import org.apache.http.client.utils.URIBuilder;
 import org.apache.http.impl.client.DefaultHttpClient;
 import org.apache.http.impl.conn.PoolingClientConnectionManager;
 import org.apache.http.message.BasicNameValuePair;
+import org.apache.http.util.EntityUtils;
 import org.apache.jena.riot.RDFDataMgr;
 
 import com.hp.hpl.jena.graph.Triple;
@@ -70,11 +73,12 @@ public class RDFServiceSparql extends RDFServiceImpl implements RDFService {
 	private static final Log log = LogFactory.getLog(RDFServiceImpl.class);
 	protected String readEndpointURI;	
 	protected String updateEndpointURI;
-    protected DefaultHttpClient httpClient;
 	                                            // the number of triples to be
 	private static final int CHUNK_SIZE = 1000; // added/removed in a single
 	                                            // SPARQL UPDATE
 
+	protected HttpClient httpClient;
+
 	/**
      * Returns an RDFService for a remote repository 
      * @param String - URI of the read SPARQL endpoint for the knowledge base
@@ -89,10 +93,7 @@ public class RDFServiceSparql extends RDFServiceImpl implements RDFService {
     public RDFServiceSparql(String readEndpointURI, String updateEndpointURI, String defaultWriteGraphURI) {
         this.readEndpointURI = readEndpointURI;
         this.updateEndpointURI = updateEndpointURI;
-
+		httpClient = HttpClientFactory.getHttpClient();
-        PoolingClientConnectionManager cm = new PoolingClientConnectionManager();
-        cm.setDefaultMaxPerRoute(50);
-        this.httpClient = new DefaultHttpClient(cm);
 
         testConnection();
     }
@@ -302,6 +303,7 @@ public class RDFServiceSparql extends RDFServiceImpl implements RDFService {
         	HttpGet meth = new HttpGet(new URIBuilder(readEndpointURI).addParameter("query", queryStr).build());
             meth.addHeader("Accept", "application/sparql-results+xml");
 			HttpResponse response = httpClient.execute(meth);
+			try {
 				int statusCode = response.getStatusLine().getStatusCode();
 				if (statusCode > 399) {
 					log.error("response " + statusCode + " to query. \n");
@@ -332,6 +334,9 @@ public class RDFServiceSparql extends RDFServiceImpl implements RDFService {
 							outputStream.toByteArray());
 					return result;
 				}
+			} finally {
+				EntityUtils.consume(response.getEntity());
+			}
 		} catch (IOException ioe) {
             throw new RuntimeException(ioe);
         } catch (URISyntaxException e) {
@@ -347,6 +352,7 @@ public class RDFServiceSparql extends RDFServiceImpl implements RDFService {
 			HttpGet meth = new HttpGet(new URIBuilder(readEndpointURI).addParameter("query", queryStr).build());
 			meth.addHeader("Accept", "application/sparql-results+xml");
 			HttpResponse response = httpClient.execute(meth);
+			try {
 				int statusCode = response.getStatusLine().getStatusCode();
 				if (statusCode > 399) {
 					log.error("response " + statusCode + " to query. \n");
@@ -357,6 +363,9 @@ public class RDFServiceSparql extends RDFServiceImpl implements RDFService {
 				try (InputStream in = response.getEntity().getContent()) {
 					consumer.processResultSet(ResultSetFactory.fromXML(in));
 				}
+			} finally {
+				EntityUtils.consume(response.getEntity());
+			}
 		} catch (IOException ioe) {
 			throw new RuntimeException(ioe);
 		} catch (URISyntaxException e) {
@@ -499,12 +508,16 @@ public class RDFServiceSparql extends RDFServiceImpl implements RDFService {
             meth.addHeader("Content-Type", "application/x-www-form-urlencoded");
             meth.setEntity(new UrlEncodedFormEntity(Arrays.asList(new BasicNameValuePair("update", updateString))));
 			HttpResponse response = httpClient.execute(meth);
+			try {
 				int statusCode = response.getStatusLine().getStatusCode();
 				if (statusCode > 399) {
 					log.error("response " + response.getStatusLine() + " to update. \n");
 					//log.debug("update string: \n" + updateString);
 					throw new RDFServiceException("Unable to perform SPARQL UPDATE");
 				}
+			} finally {
+				EntityUtils.consume(response.getEntity());
+			}
         } catch (Exception e) {
             throw new RDFServiceException("Unable to perform change set update", e);
         } 

webapp/src/edu/cornell/mannlib/vitro/webapp/rdfservice/impl/virtuoso/RDFServiceVirtuoso.java

@@ -7,6 +7,7 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.UnsupportedEncodingException;
 
+import org.apache.commons.httpclient.HttpMethod;
 import org.apache.commons.io.IOUtils;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -23,6 +24,7 @@ import org.apache.http.protocol.HttpContext;
 
 import edu.cornell.mannlib.vitro.webapp.rdfservice.RDFServiceException;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.impl.sparql.RDFServiceSparql;
+import org.apache.http.util.EntityUtils;
 
 /**
  * For now, at least, it is just like an RDFServiceSparql except:
@@ -78,8 +80,10 @@ public class RDFServiceVirtuoso extends RDFServiceSparql {
 		log.debug("UPDATE STRING: " + updateString);
 
 		try {
+			HttpPost request = createHttpRequest(updateString);
 			HttpResponse response = httpClient.execute(
-					createHttpRequest(updateString), createHttpContext());
+					request, createHttpContext());
+			try {
 				int statusCode = response.getStatusLine().getStatusCode();
 				if (statusCode > 399) {
 					log.error("response " + response.getStatusLine()
@@ -95,6 +99,9 @@ public class RDFServiceVirtuoso extends RDFServiceSparql {
 							"Unable to perform SPARQL UPDATE: status code = "
 									+ statusCode);
 				}
+			} finally {
+				EntityUtils.consume(response.getEntity());
+			}
 		} catch (Exception e) {
 			log.error("Failed to update: " + updateString, e);
 			throw new RDFServiceException(

webapp/src/edu/cornell/mannlib/vitro/webapp/utils/http/HttpClientFactory.java

@@ -0,0 +1,22 @@
+/* $This file is distributed under the terms of the license in /doc/license.txt$ */
+
+package edu.cornell.mannlib.vitro.webapp.utils.http;
+
+import org.apache.http.client.HttpClient;
+import org.apache.http.impl.client.DefaultHttpClient;
+import org.apache.http.impl.conn.PoolingClientConnectionManager;
+
+public final class HttpClientFactory {
+    private static final DefaultHttpClient httpClient;
+
+    static {
+        PoolingClientConnectionManager cm = new PoolingClientConnectionManager();
+        cm.setDefaultMaxPerRoute(50);
+        cm.setMaxTotal(300);
+        httpClient = new DefaultHttpClient(cm);
+    }
+
+    public static HttpClient getHttpClient() {
+        return httpClient;
+    }
+}