First_Application_Tutorial
Create maven project in Eclipse using Blazegraph in embedded mode with Sesame API. You need Eclipse IDE for Java Developer with Maven integration to begin.
Select File->New->Project and choose Maven project in a dialog window.
Click Next and make you sure the option 'Create a simple project' is checked in the dialog box:
Click 'Next' again. In the next dialog box specify Maven project details:
Click 'Finish'. Now you have an Eclipse Maven project.
Open the pom.xml file of your project and add the following lines:
<repositories>
<repository>
<id>bigdata.releases</id>
<url>http://www.systap.com/maven/releases</url>
</repository>
</repositories>
<dependencies>
<dependency>
<groupId>com.bigdata</groupId>
<artifactId>bigdata</artifactId>
<version>1.5.1</version>
</dependency>
</dependencies>
Save pom.xml. All necessary Blazegraph dependencies will be automatically downloaded, updated, and have their sub-dependencies managed by Maven.
Create file log4j.properties in /src/main/resources folder. Copy the following code in it.
log4j.rootCategory=WARN, dest1
log4j.logger.com.bigdata=ERROR
log4j.logger.com.blazegraph.sample-sesame-local=INFO
log4j.appender.dest1=org.apache.log4j.ConsoleAppender
log4j.appender.dest1.layout=org.apache.log4j.PatternLayout
We are going to create a simple application which uploads a statement to the Blazegraph local store:
<http://blazegraph.com/Blazegraph> <http://blazegraph.com/says> "hello"^^<http://www.w3.org/2001/XMLSchema#string> .
Then we want to retrieve it by evaluating a SPARQL query:
select ?p ?o where {<http://blazegraph.com/Blazegraph> ?p ?o .}
We will connect to Blazegraph using Sesame API.
Right-click on src/main/java and select New->Class. In the dialog fill in the class name (HelloBlazegraph in example) and make sure public static void main (String[] args) is checked.
Click 'Finish' and Eclipse will create the new class and automatically open it in an editor.
Insert the following code to HelloBlazegraph.java.
import java.util.Properties;
import org.openrdf.OpenRDFException;
import org.openrdf.model.Literal;
import org.openrdf.model.Statement;
import org.openrdf.model.impl.LiteralImpl;
import org.openrdf.model.impl.StatementImpl;
import org.openrdf.model.impl.URIImpl;
import org.openrdf.query.BindingSet;
import org.openrdf.query.QueryLanguage;
import org.openrdf.query.TupleQuery;
import org.openrdf.query.TupleQueryResult;
import org.openrdf.repository.Repository;
import org.openrdf.repository.RepositoryConnection;
import com.bigdata.journal.Options;
import com.bigdata.rdf.sail.BigdataSail;
import com.bigdata.rdf.sail.BigdataSailRepository;
public class HelloBlazegraph {
public static void main(String[] args) throws OpenRDFException {
final Properties props = new Properties();
props.put(Options.BUFFER_MODE, "DiskRW"); // persistent file system located journal
props.put(Options.FILE, "/tmp/blazegraph/test.jnl"); // journal file location
final BigdataSail sail = new BigdataSail(props); // instantiate a sail
final Repository repo = new BigdataSailRepository(sail); // create a Sesame repository
repo.initialize();
try {
// prepare a statement
URIImpl subject = new URIImpl("http://blazegraph.com/Blazegraph");
URIImpl predicate = new URIImpl("http://blazegraph.com/says");
Literal object = new LiteralImpl("hello");
Statement stmt = new StatementImpl(subject, predicate, object);
// open repository connection
RepositoryConnection cxn = repo.getConnection();
// upload data to repository
try {
cxn.begin();
cxn.add(stmt);
cxn.commit();
} catch (OpenRDFException ex) {
cxn.rollback();
throw ex;
} finally {
// close the repository connection
cxn.close();
}
// open connection
if (repo instanceof BigdataSailRepository) {
cxn = ((BigdataSailRepository) repo).getReadOnlyConnection();
} else {
cxn = repo.getConnection();
}
// evaluate sparql query
try {
final TupleQuery tupleQuery = cxn
.prepareTupleQuery(QueryLanguage.SPARQL,
"select ?p ?o where { <http://blazegraph.com/Blazegraph> ?p ?o . }");
TupleQueryResult result = tupleQuery.evaluate();
try {
while (result.hasNext()) {
BindingSet bindingSet = result.next();
System.err.println(bindingSet);
}
} finally {
result.close();
}
} finally {
// close the repository connection
cxn.close();
}
} finally {
repo.shutDown();
}
}
}
After running the application, you will see the following in your Eclipse console :
BlazeGraph(TM) Graph Engine
Flexible
Reliable
Affordable
Web-Scale Computing for the Enterprise
Copyright SYSTAP, LLC 2006-2015. All rights reserved.
192.168.3.3
Tue Apr 21 17:31:49 YEKT 2015
Linux/3.13.0-49-generic amd64
AMD FX(tm)-6100 Six-Core Processor Family 21 Model 1 Stepping 2, AuthenticAMD #CPU=6
Oracle Corporation 1.8.0_40
freeMemory=237754792
buildVersion=1.5.1
Dependency License
ICU http://source.icu-project.org/repos/icu/icu/trunk/license.html
bigdata-ganglia http://www.apache.org/licenses/LICENSE-2.0.html
blueprints-core https://github.com/tinkerpop/blueprints/blob/master/LICENSE.txt
colt http://acs.lbl.gov/software/colt/license.html
commons-codec http://www.apache.org/licenses/LICENSE-2.0.html
commons-fileupload http://www.apache.org/licenses/LICENSE-2.0.html
commons-io http://www.apache.org/licenses/LICENSE-2.0.html
commons-logging http://www.apache.org/licenses/LICENSE-2.0.html
dsiutils http://www.gnu.org/licenses/lgpl-2.1.html
fastutil http://www.apache.org/licenses/LICENSE-2.0.html
flot http://www.opensource.org/licenses/mit-license.php
high-scale-lib http://creativecommons.org/licenses/publicdomain
httpclient http://www.apache.org/licenses/LICENSE-2.0.html
httpclient-cache http://www.apache.org/licenses/LICENSE-2.0.html
httpcore http://www.apache.org/licenses/LICENSE-2.0.html
httpmime http://www.apache.org/licenses/LICENSE-2.0.html
jackson-core http://www.apache.org/licenses/LICENSE-2.0.html
jetty http://www.apache.org/licenses/LICENSE-2.0.html
jquery https://github.com/jquery/jquery/blob/master/MIT-LICENSE.txt
log4j http://www.apache.org/licenses/LICENSE-2.0.html
lucene http://www.apache.org/licenses/LICENSE-2.0.html
nanohttp http://elonen.iki.fi/code/nanohttpd/#license
rexster-core https://github.com/tinkerpop/rexster/blob/master/LICENSE.txt
river http://www.apache.org/licenses/LICENSE-2.0.html
servlet-api http://www.apache.org/licenses/LICENSE-2.0.html
sesame http://www.openrdf.org/download.jsp
slf4j http://www.slf4j.org/license.html
zookeeper http://www.apache.org/licenses/LICENSE-2.0.html
INFO: com.bigdata.util.config.LogUtil: Configure: file:/home/maria/workspace_sample/sample-sesame-local/target/classes/log4j.properties
New service class org.openrdf.query.resultio.sparqljson.SPARQLResultsJSONWriterFactory replaces existing service class com.bigdata.rdf.rio.json.BigdataSPARQLResultsJSONWriterFactory
New service class org.openrdf.query.resultio.sparqljson.SPARQLResultsJSONParserFactory replaces existing service class com.bigdata.rdf.rio.json.BigdataSPARQLResultsJSONParserFactory
[p=http://blazegraph.com/says;o="hello"]
