Apache Jena
Revision as of 10:12, 28 June 2020 by Wf (talk | contribs) (→SSH tunnel to make port 3030 available)
What is Apache Jena?
- https://jena.apache.org/
- https://en.wikipedia.org/wiki/Apache_Jena
- https://en.wikipedia.org/wiki/Draft:Apache_Fuseki (Draft in progress/review as of 2020-06-28)
- https://www.wikidata.org/wiki/Q1686799
Setting up an Apache Jena instance, loading some data and starting a Fuseki server
When i first tried to get Apache Jena and the Fuseki server running i had some issues doing so. This page is to share how i solved the issues e.g.
Script to download Apache jena and load initial data with tdb2.tdbloader
#!/bin/bash
# WF 2020-05-10
# global settings
jena=apache-jena-3.15.0
tgz=$jena.tar.gz
jenaurl=http://mirror.easyname.ch/apache/jena/binaries/$tgz
base=/hd/luxio/gnd
data=$base/data
tdbloader=$jena/bin/tdb2.tdbloader
getjena() {
# download
if [ ! -f $tgz ]
then
echo "downloading $tgz from $jenaurl"
wget $jenaurl
else
echo "$tgz already downloaded"
fi
# unpack
if [ ! -d $jena ]
then
echo "unpacking $jena from $tgz"
tar xvzf $tgz
else
echo "$jena already unpacked"
fi
# create data directory
if [ ! -d $data ]
then
echo "creating $data directory"
mkdir -p $data
else
echo "$data directory already created"
fi
}
#
# show the given timestamp
#
timestamp() {
local msg="$1"
local ts=$(date -u +"%Y-%m-%dT%H:%M:%SZ")
echo "$msg at $ts"
}
#
# load data for the given data dir and input
#
loaddata() {
local data="$1"
local input="$2"
timestamp "start loading $input to $data"
$tdbloader --loader=parallel --loc "$data" "$input" > tdb2-$phase-out.log 2> tdb2-$phase-err.log
timestamp "finished loading $input to $data"
}
getjena
export TMPDIR=$base/tmp
if [ ! -d $TMPDIR ]
then
echo "creating temporary directory $TMPDIR"
mkdir $TMPDIR
else
echo "using temporary directory $TMPDIR"
fi
if [ ! -f authorities-kongress_lds.ttl ]
then
wget https://data.dnb.de/opendata/authorities-kongress_lds.ttl.gz
gunzip authorities-kongress_lds.ttl.gz
fi
loaddata $data authorities-kongress_lds.ttl
Script to start Fuseki server
#!/bin/bash
# WF 2020-06-25
# Jena Fuseki server installation
# see https://jena.apache.org/documentation/fuseki2/fuseki-run.html
version=3.14.0
fuseki=apache-jena-fuseki-$version
if [ ! -d $fuseki ]
then
if [ ! -f $fuseki.tar.gz ]
then
wget http://archive.apache.org/dist/jena/binaries/$fuseki.tar.gz
else
echo $fuseki.tar.gz already downloaded
fi
echo "unpacking $fuseki.tar.gz"
tar xvfz $fuseki.tar.gz
else
echo $fuseki already downloaded and unpacked
fi
cd $fuseki
java -jar fuseki-server.jar --tdb2 --loc=../data /gnd
SSH tunnel to make port 3030 available
The default installation of Fuseki only allows connections from localhost. If you don't want to bother with the configuration you can use a SSH tunnel like this:
ssh -L 3030:localhost:3030 capri.bitplan.com
replacing capri.bitplan.com with the name of the server you are using. While the above ssh session is active you'll be able to point your browser to http://localhost:3030 and the Apache admin Web GUI will show and be functional.
Script to start Jena on boot =
You might want to adapt the harddisk location where you keep your jena/fuseki installation and adapt the script name "fuseki" which is the script for starting Fuseki shown above.
#
# start Apache jena server
#
startJena() {
cd /hd/luxio/gnd
log=/var/log/jena.log
sudo touch $log
sudo chmod 666 $log
nohup sudo ./fuseki > /var/log/jena.log 2>&1 &
}
startJena
RDF API Tutorial examples
see https://jena.apache.org/tutorials/rdf_api.html
Script to compile and run tutorial examples
#!/bin/bash
# WF 2020-06-14
num=$1
pwd=$(pwd)
base=$pwd/apache-jena-3.15.0
cd $base/src-examples
echo compiling Tutorial $num
javac -cp "$base/lib/*" jena/examples/rdf/Tutorial$num.java
echo running Tutorial $num
java -cp ".:$base/lib/*" jena/examples/rdf/Tutorial$num
Tutorial03.java
Java Code
/** Tutorial 3 Statement attribute accessor methods
*/
public class Tutorial03 extends Object {
public static void main (String args[]) {
// some definitions
String personURI = "http://somewhere/JohnSmith";
String givenName = "John";
String familyName = "Smith";
String fullName = givenName + " " + familyName;
// create an empty model
Model model = ModelFactory.createDefaultModel();
// create the resource
// and add the properties cascading style
Resource johnSmith
= model.createResource(personURI)
.addProperty(VCARD.FN, fullName)
.addProperty(VCARD.N,
model.createResource()
.addProperty(VCARD.Given, givenName)
.addProperty(VCARD.Family, familyName));
// list the statements in the graph
StmtIterator iter = model.listStatements();
// print out the predicate, subject and object of each statement
while (iter.hasNext()) {
Statement stmt = iter.nextStatement(); // get next statement
Resource subject = stmt.getSubject(); // get the subject
Property predicate = stmt.getPredicate(); // get the predicate
RDFNode object = stmt.getObject(); // get the object
System.out.print(subject.toString());
System.out.print(" " + predicate.toString() + " ");
if (object instanceof Resource) {
System.out.print(object.toString());
} else {
// object is a literal
System.out.print(" \"" + object.toString() + "\"");
}
System.out.println(" .");
}
}
}
Trying it
./ct 03
compiling Tutorial 03
running Tutorial 03
http://somewhere/JohnSmith http://www.w3.org/2001/vcard-rdf/3.0#N 7555a24e-8f13-4508-91f0-9dfb26cd2239 .
http://somewhere/JohnSmith http://www.w3.org/2001/vcard-rdf/3.0#FN "John Smith" .
7555a24e-8f13-4508-91f0-9dfb26cd2239 http://www.w3.org/2001/vcard-rdf/3.0#Family "Smith" .
7555a24e-8f13-4508-91f0-9dfb26cd2239 http://www.w3.org/2001/vcard-rdf/3.0#Given "John" .
Tutorial04.java
Java Code
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jena.examples.rdf ;
import org.apache.jena.rdf.model.*;
import org.apache.jena.vocabulary.*;
/** Tutorial 4 - create a model and write it in XML form to standard out
*/
public class Tutorial04 extends Object {
// some definitions
static String tutorialURI = "http://hostname/rdf/tutorial/";
static String briansName = "Brian McBride";
static String briansEmail1 = "brian_mcbride@hp.com";
static String briansEmail2 = "brian_mcbride@hpl.hp.com";
static String title = "An Introduction to RDF and the Jena API";
static String date = "23/01/2001";
public static void main (String args[]) {
// some definitions
String personURI = "http://somewhere/JohnSmith";
String givenName = "John";
String familyName = "Smith";
String fullName = givenName + " " + familyName;
// create an empty model
Model model = ModelFactory.createDefaultModel();
// create the resource
// and add the properties cascading style
Resource johnSmith
= model.createResource(personURI)
.addProperty(VCARD.FN, fullName)
.addProperty(VCARD.N,
model.createResource()
.addProperty(VCARD.Given, givenName)
.addProperty(VCARD.Family, familyName));
// now write the model in XML form to a file
model.write(System.out);
}
}
Trying it
./ct 04
compiling Tutorial 04
running Tutorial 04
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:vcard="http://www.w3.org/2001/vcard-rdf/3.0#">
<rdf:Description rdf:about="http://somewhere/JohnSmith">
<vcard:N rdf:parseType="Resource">
<vcard:Family>Smith</vcard:Family>
<vcard:Given>John</vcard:Given>
</vcard:N>
<vcard:FN>John Smith</vcard:FN>
</rdf:Description>
</rdf:RDF>
Tutorial05.java
Java Code
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jena.examples.rdf ;
import org.apache.jena.rdf.model.*;
import org.apache.jena.util.FileManager;
import java.io.*;
/** Tutorial 5 - read RDF XML from a file and write it to standard out
*/
public class Tutorial05 extends Object {
/**
NOTE that the file is loaded from the class-path and so requires that
the data-directory, as well as the directory containing the compiled
class, must be added to the class-path when running this and
subsequent examples.
*/
static final String inputFileName = "vc-db-1.rdf";
public static void main (String args[]) {
// create an empty model
Model model = ModelFactory.createDefaultModel();
InputStream in = FileManager.get().open( inputFileName );
if (in == null) {
throw new IllegalArgumentException( "File: " + inputFileName + " not found");
}
// read the RDF/XML file
model.read(in, "");
// write it to standard out
model.write(System.out);
}
}
Try it!
wget https://jena.apache.org/tutorials/sparql_data/vc-db-1.rdf
mv vc-db-1.rdf apache-jena-3.15.0/src-examples/
./ct 05
compiling Tutorial 05
running Tutorial 05
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:vCard="http://www.w3.org/2001/vcard-rdf/3.0#">
<rdf:Description rdf:about="http://somewhere/SarahJones">
<vCard:N rdf:parseType="Resource">
<vCard:Given>Sarah</vCard:Given>
<vCard:Family>Jones</vCard:Family>
</vCard:N>
<vCard:FN>Sarah Jones</vCard:FN>
</rdf:Description>
<rdf:Description rdf:about="http://somewhere/JohnSmith">
<vCard:N rdf:parseType="Resource">
<vCard:Given>John</vCard:Given>
<vCard:Family>Smith</vCard:Family>
</vCard:N>
<vCard:FN>John Smith</vCard:FN>
</rdf:Description>
<rdf:Description rdf:about="http://somewhere/MattJones">
<vCard:N rdf:parseType="Resource">
<vCard:Given>Matthew</vCard:Given>
<vCard:Family>Jones</vCard:Family>
</vCard:N>
<vCard:FN>Matt Jones</vCard:FN>
</rdf:Description>
<rdf:Description rdf:about="http://somewhere/RebeccaSmith">
<vCard:N rdf:parseType="Resource">
<vCard:Given>Rebecca</vCard:Given>
<vCard:Family>Smith</vCard:Family>
</vCard:N>
<vCard:FN>Becky Smith</vCard:FN>
</rdf:Description>
</rdf:RDF>
Tutorial06.java
Java Code
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jena.examples.rdf ;
import org.apache.jena.rdf.model.*;
import org.apache.jena.util.FileManager;
import org.apache.jena.vocabulary.*;
import java.io.*;
/** Tutorial navigating a model
*/
public class Tutorial06 extends Object {
static final String inputFileName = "vc-db-1.rdf";
static final String johnSmithURI = "http://somewhere/JohnSmith";
public static void main (String args[]) {
// create an empty model
Model model = ModelFactory.createDefaultModel();
// use the FileManager to find the input file
InputStream in = FileManager.get().open(inputFileName);
if (in == null) {
throw new IllegalArgumentException( "File: " + inputFileName + " not found");
}
// read the RDF/XML file
model.read(new InputStreamReader(in), "");
// retrieve the Adam Smith vcard resource from the model
Resource vcard = model.getResource(johnSmithURI);
// retrieve the value of the N property
Resource name = (Resource) vcard.getRequiredProperty(VCARD.N)
.getObject();
// retrieve the given name property
String fullName = vcard.getRequiredProperty(VCARD.FN)
.getString();
// add two nick name properties to vcard
vcard.addProperty(VCARD.NICKNAME, "Smithy")
.addProperty(VCARD.NICKNAME, "Adman");
// set up the output
System.out.println("The nicknames of \"" + fullName + "\" are:");
// list the nicknames
StmtIterator iter = vcard.listProperties(VCARD.NICKNAME);
while (iter.hasNext()) {
System.out.println(" " + iter.nextStatement().getObject()
.toString());
}
}
}
Try it!
./ct 06
compiling Tutorial 06
running Tutorial 06
The nicknames of "John Smith" are:
Adman
Smithy
Tutorial07.java
Java Code
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jena.examples.rdf ;
import org.apache.jena.rdf.model.*;
import org.apache.jena.util.FileManager;
import org.apache.jena.vocabulary.*;
import java.io.*;
/** Tutorial 7 - selecting the VCARD resources
*/
public class Tutorial07 extends Object {
static final String inputFileName = "vc-db-1.rdf";
public static void main (String args[]) {
// create an empty model
Model model = ModelFactory.createDefaultModel();
// use the FileManager to find the input file
InputStream in = FileManager.get().open(inputFileName);
if (in == null) {
throw new IllegalArgumentException( "File: " + inputFileName + " not found");
}
// read the RDF/XML file
model.read( in, "");
// select all the resources with a VCARD.FN property
ResIterator iter = model.listResourcesWithProperty(VCARD.FN);
if (iter.hasNext()) {
System.out.println("The database contains vcards for:");
while (iter.hasNext()) {
System.out.println(" " + iter.nextResource()
.getRequiredProperty(VCARD.FN)
.getString() );
}
} else {
System.out.println("No vcards were found in the database");
}
}
}
Try it !
compiling Tutorial 07
running Tutorial 07
The database contains vcards for:
Sarah Jones
John Smith
Matt Jones
Becky Smith
Tutorial08.java
Java Code
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jena.examples.rdf ;
import org.apache.jena.rdf.model.*;
import org.apache.jena.util.FileManager;
import org.apache.jena.vocabulary.*;
import java.io.*;
/** Tutorial 8 - demonstrate Selector methods
*/
public class Tutorial08 extends Object {
static final String inputFileName = "vc-db-1.rdf";
public static void main (String args[]) {
// create an empty model
Model model = ModelFactory.createDefaultModel();
// use the FileManager to find the input file
InputStream in = FileManager.get().open(inputFileName);
if (in == null) {
throw new IllegalArgumentException( "File: " + inputFileName + " not found");
}
// read the RDF/XML file
model.read( in, "" );
// select all the resources with a VCARD.FN property
// whose value ends with "Smith"
StmtIterator iter = model.listStatements(
new
SimpleSelector(null, VCARD.FN, (RDFNode) null) {
@Override
public boolean selects(Statement s) {
return s.getString().endsWith("Smith");
}
});
if (iter.hasNext()) {
System.out.println("The database contains vcards for:");
while (iter.hasNext()) {
System.out.println(" " + iter.nextStatement()
.getString());
}
} else {
System.out.println("No Smith's were found in the database");
}
}
}
Try it !
./ct 08
compiling Tutorial 08
running Tutorial 08
The database contains vcards for:
Becky Smith
John Smith