类CreateSequence表明了如何将一系列服务串联起来，并自动产生一个描述新服务的profile，这个类假定每个服务都是单输入单输出的（除了第一个服务和最后一个服务），这样前面的服务的输出将作为后一个服务的输入。第一个服务不需要有输入，最后一个服务不需要有输出。组合服务的名字命名为[Service1 + Service2 + ... + ServiceN]。最后在main函数中进行测试，将BookFinder.owl和BNPrice.owl进行组合，输入"City of Glass"，先查通过BookFinder.owl查到书号，然后将书号输入BNPrice.owl，得到输出：
Executing...done
Book Price =
Price:
currency: USD
amount: 14.00
完整代码如下：
import java.net.URI;
import java.util.ArrayList;
import java.util.List;
import org.mindswap.owl.EntityFactory;
import org.mindswap.owl.OWLFactory;
import org.mindswap.owl.OWLIndividual;
import org.mindswap.owl.OWLKnowledgeBase;
import org.mindswap.owl.OWLOntology;
import org.mindswap.owls.OWLSFactory;
import org.mindswap.owls.grounding.Grounding;
import org.mindswap.owls.process.AtomicProcess;
import org.mindswap.owls.process.CompositeProcess;
import org.mindswap.owls.process.Input;
import org.mindswap.owls.process.Output;
import org.mindswap.owls.process.Perform;
import org.mindswap.owls.process.Process;
import org.mindswap.owls.process.ProcessList;
import org.mindswap.owls.process.Result;
import org.mindswap.owls.process.Sequence;
import org.mindswap.owls.process.execution.ProcessExecutionEngine;
import org.mindswap.owls.profile.Profile;
import org.mindswap.owls.service.Service;
import org.mindswap.query.ValueMap;
import org.mindswap.utils.URIUtils;
import org.mindswap.utils.Utils;
/**
* An example to show how service descriptions can be created on the fly, saved and executed.
*
* @author Evren Sirin
*/
public class CreateSequence {
public static final URI baseURI = URI.create("http://www.example.org/BookPrice.owl#");
OWLOntology ont;
public CreateSequence() {
}
/**
*
* Create a new Sequence from the processes of the given services and put them in a new
* Service object with a automatically generated Profile. This function assumes that
* each service in the list has exactly one input and one output (except the first and
* last one) such that in the resulting Service the output of each service will be fed
* as input to the next one. The first service does not have to have an input and the
* last one does not need to have an output. The resulting service will have an input
* (or an output) depending on this.
*
* @param services List of Service objects
* @param baseURI The base URI for the generated service
* @return The Service which is a Sequence of the given services
*/
Service createSequenceService(List services) {
Service service = ont.createService(URIUtils.createURI(baseURI, "TestService"));
CompositeProcess process = ont.createCompositeProcess(URIUtils.createURI(baseURI, "TestProcess"));
Profile profile = ont.createProfile(URIUtils.createURI(baseURI, "TestProfile"));
Grounding grounding = ont.createGrounding(URIUtils.createURI(baseURI, "TestGrounding"));
System.out.println(ont.getKB().getServices());
service.setProfile(profile);
service.setProcess(process);
service.setGrounding(grounding);
createSequenceProcess(process, services);
createProfile(profile, process);
ProcessList list = process.getComposedOf().getAllProcesses();
for(int i = 0; i < list.size(); i++) {
Process pc = list.processAt(i);
if(pc instanceof AtomicProcess) {
grounding.addGrounding(((AtomicProcess)pc).getGrounding());
}
}
profile.setLabel(createLabel(services));
profile.setTextDescription(profile.getLabel());
service.setProfile(profile);
service.setProcess(process);
service.setGrounding(grounding);
return service;
}
/**
*
* Create a label for the composite service based on the labels of services. Basically
* return the string [Service1 + Service2 + ... + ServiceN] as the label
*
* @param services List of Servie objects
* @return
*/
String createLabel(List services) {
String label = "[";
for(int i = 0; i < services.size(); i++) {
Service s = (Service) services.get(i);
if(i > 0) label += " + ";
label += s.getLabel();
}
label += "]";
return label;
}
/**
*
* Create a Profile for the composite service. We only set the input and output of the profile
* based on the process.
*
* @param profile
* @param process
* @return
*/
Profile createProfile(Profile profile, Process process) {
for(int i = 0; i < process.getInputs().size(); i++) {
Input input = process.getInputs().inputAt(i);
profile.addInput(input);
}
for(int i = 0; i < process.getOutputs().size(); i++) {
Output output = process.getOutputs().outputAt(i);
profile.addOutput(output);
}
return profile;
}
/**
*
* Create a Sequence process for the processes of given services. Creates the DataFlow asssuming each
* service has one output and one intput (except first and last one).
*
* @param compositeProcess
* @param grounding
* @param services
* @return
*/
CompositeProcess createSequenceProcess(CompositeProcess compositeProcess, List services) {
Sequence sequence = ont.createSequence();
compositeProcess.setComposedOf(sequence);
Perform[] performs = new Perform[services.size()];
for(int i = 0; i < services.size(); i++) {
Service s = (Service) services.get(i);
Process p = s.getProcess();
performs[i] = ont.createPerform();
performs[i].setProcess(p);
sequence.addComponent(performs[i]);
if(i > 0) {
Perform prevPerform = performs[i - 1];
Input input = p.getInputs().inputAt(0);
Output output = prevPerform.getProcess().getOutputs().outputAt(0);
// the value of 'input' is the value of 'output' from 'prevPerform'
performs[i].addBinding(input, prevPerform, output);
}
}
Perform firstPerform = performs[0];
Perform lastPerform = performs[services.size()-1];
boolean createInput = firstPerform.getProcess().getInputs().size() > 0;
boolean createOutput = lastPerform.getProcess().getOutputs().size() > 0;
if(createInput) {
Input input = firstPerform.getProcess().getInputs().inputAt(0);
Input newInput = ont.createInput(URIUtils.createURI(baseURI, "TestInput"));
newInput.setLabel(input.getLabel());
newInput.setParamType(input.getParamType());
newInput.setProcess(compositeProcess);
// input of the first perform is directly read from the input of the
// composite process
performs[0].addBinding(input, Perform.TheParentPerform, newInput);
}
if(createOutput) {
Output output = lastPerform.getProcess().getOutputs().outputAt(0);
Output newOutput = ont.createOutput(URIUtils.createURI(baseURI, "TestOutput"));
newOutput.setLabel(output.getLabel());
newOutput.setParamType(output.getParamType());
newOutput.setProcess(compositeProcess);
// the output of the composite process is the output pf last process
Result result = ont.createResult();
result.addBinding(newOutput, lastPerform, output);
compositeProcess.setResult(result);
}
return compositeProcess;
}
public void runTest() throws Exception {
// create an OWL-S knowledge base
OWLKnowledgeBase kb = OWLFactory.createKB();
// create an empty ontology in this KB
ont = kb.createOntology();
// create an execution engine
ProcessExecutionEngine exec = OWLSFactory.createExecutionEngine();
// load two services
Service s1 = kb.readService("http://www.mindswap.org/2004/owl-s/1.1/BookFinder.owl#");
Service s2 = kb.readService("http://www.mindswap.org/2004/owl-s/1.1/BNPrice.owl#");
// put the services in a list
List services = new ArrayList();
services.add(s1);
services.add(s2);
// create a new service as a sequence of the list
Service s = createSequenceService(services);
// print the description of new service to standard output
ont.write(System.out, baseURI);
System.out.println();
// get the process of the new service
Process process = s.getProcess();
// initialize the input values to be empty
ValueMap values = new ValueMap();
// get the parameter using the local name
values.setValue(process.getInputs().inputAt(0), EntityFactory.createDataValue("City of Glass"));
// execute the service
System.out.print("Executing...");
values = exec.execute(process, values);
System.out.println("done");
// get the output param using the index
OWLIndividual outValue = values.getIndividualValue(process.getOutput());
// display the result
System.out.println("Book Price = ");
System.out.println(Utils.formatRDF(outValue.toRDF()));
System.out.println();
}
public static void main(String[] args) throws Exception {
CreateSequence test = new CreateSequence();
test.runTest();
}
}
ForEachExample类是对多输入值进行操作的例子，例如，分别输入三个邮政编码，然后调用服务得到三个地区的纬度和经度。
完整代码如下：
import impl.owls.process.execution.ProcessExecutionEngineImpl;
import java.net.URI;
import org.mindswap.owl.OWLClass;
import org.mindswap.owl.OWLDataProperty;
import org.mindswap.owl.OWLFactory;
import org.mindswap.owl.OWLIndividual;
import org.mindswap.owl.OWLKnowledgeBase;
import org.mindswap.owl.OWLOntology;
import org.mindswap.owl.list.RDFList;
import org.mindswap.owls.OWLSFactory;
import org.mindswap.owls.process.CompositeProcess;
import org.mindswap.owls.process.ForEach;
import org.mindswap.owls.process.Input;
import org.mindswap.owls.process.Local;
import org.mindswap.owls.process.Perform;
import org.mindswap.owls.process.Process;
import org.mindswap.owls.process.execution.ProcessExecutionEngine;
import org.mindswap.owls.service.Service;
import org.mindswap.owls.vocabulary.OWLS;
import org.mindswap.query.ValueMap;
/**
*
* Example to show how to create and execute a forEach control construct.
*
* @author Evren Sirin
*/
public class ForEachExample {
public void run() throws Exception {
String ns = "http://www.example.org/test#";
// print the inputs and outputs during each iteration of the loop
ProcessExecutionEngineImpl.DEBUG = true;
ProcessExecutionEngine exec = OWLSFactory.createExecutionEngine();
OWLKnowledgeBase kb = OWLFactory.createKB();
Service service = kb.readService("http://www.mindswap.org/2004/owl-s/1.1/FindLatLong.owl");
Process process = service.getProcess();
OWLOntology ont = kb.createOntology();
CompositeProcess cp = ont.createCompositeProcess();
Input in = ont.createInput(URI.create( ns + "in" ));
in.setParamType(OWLS.ObjList.List());
cp.addInput(in);
// create a ForEach construct
ForEach forEach = ont.createForEach();
Local loopVar = ont.createLocal( URI.create( ns + "loopVar") );
cp.setComposedOf(forEach);
forEach.setListValue( Perform.TheParentPerform, in );
forEach.setLoopVar( loopVar );
// perform the process by passing the loop variable
Perform perform = ont.createPerform();
perform.setProcess(process);
perform.addBinding(process.getInput(), Perform.TheParentPerform, loopVar);
forEach.setComponent(perform);
// display how the construct looks like in RDF/XML
ont.write(System.out);
// create some zip code values
String zipcodeOnt = "http://www.daml.org/2001/10/html/zipcode-ont#";
OWLClass ZipCode = kb.getClass(URI.create(zipcodeOnt + "ZipCode"));
OWLDataProperty zip = kb.getDataProperty(URI.create(zipcodeOnt + "zip"));
OWLIndividual zip1 = ont.createInstance(ZipCode);
zip1.setProperty(zip, "20740");
OWLIndividual zip2 = ont.createInstance(ZipCode);
zip2.setProperty(zip, "11430");
OWLIndividual zip3 = ont.createInstance(ZipCode);
zip3.setProperty(zip, "94102");
// put them in a list
RDFList list = ont.createList(zip1).add(zip2).add(zip3);
ValueMap values = new ValueMap();
values.setValue(cp.getInput("in"), list);
exec.execute( cp , values );
}
public static void main(String[] args) throws Exception {
ForEachExample test = new ForEachExample();
test.run();
}
}
运行后得到输出：
Executing AtomicProcess http://www.mindswap.org/2004/owl-s/1.1/FindLobjectatLong.owl#FindLatLongProcess
Inputs:
(http://www.mindswap.org/2004/owl-s/1.1/FindLobjectatLong.owl#ZipCode=
<j.0:ZipCode>
<j.0:zip>20740</j.0:zip>
</j.0:ZipCode>
)
Invoking http://cheeso.members.winisp.net/zips/ZipService.asmx?WSDL
Result:
(http://www.mindswap.org/2004/owl-s/1.1/FindLobjectatLong.owl#LatLong=
<j.0:LatLon>
<j.0:latitude>38.996303</j.0:latitude>
<j.0:longitude>-76.929891</j.0:longitude>
</j.0:LatLon>
)
Executing AtomicProcess http://www.mindswap.org/2004/owl-s/1.1/FindLobjectatLong.owl#FindLatLongProcess
Inputs:
(http://www.mindswap.org/2004/owl-s/1.1/FindLobjectatLong.owl#ZipCode=
<rdf:Description>
<j.0:zip>11430</j.0:zip>
</rdf:Description>
)
Invoking http://cheeso.members.winisp.net/zips/ZipService.asmx?WSDL
Result:
(http://www.mindswap.org/2004/owl-s/1.1/FindLobjectatLong.owl#LatLong=
<j.0:LatLon>
<j.0:latitude>-0</j.0:latitude>
<j.0:longitude>-0</j.0:longitude>
</j.0:LatLon>
)
Executing AtomicProcess http://www.mindswap.org/2004/owl-s/1.1/FindLobjectatLong.owl#FindLatLongProcess
Inputs:
(http://www.mindswap.org/2004/owl-s/1.1/FindLobjectatLong.owl#ZipCode=
<rdf:Description>
<j.0:zip>94102</j.0:zip>
</rdf:Description>
)
Invoking http://cheeso.members.winisp.net/zips/ZipService.asmx?WSDL
Result:
(http://www.mindswap.org/2004/owl-s/1.1/FindLobjectatLong.owl#LatLong=
<j.0:LatLon>
<j.0:latitude>-0</j.0:latitude>
<j.0:longitude>-0</j.0:longitude>
</j.0:LatLon>
)
Matchmaker这个例子说明了如何对服务进行匹配，实现服务的组合。服务的输出与服务的输入进行匹配，分别运用"EXACT, SUBSUME以及RELAXED"作为匹配标准。这里应用了Pellet推理机。
对以下几个文件进行输入输出皮匹配：
http://www.mindswap.org/2004/owl-s/1.1/BNPrice.owl
http://www.mindswap.org/2004/owl-s/1.1/BookFinder.owl
http://www.mindswap.org/2004/owl-s/1.1/CurrencyConverter.owl
http://www.mindswap.org/2004/owl-s/1.1/Dictionary.owl
http://www.mindswap.org/2004/owl-s/1.1/ZipCodeFinder.owl
http://www.mindswap.org/2004/owl-s/1.1/FindLatLong.owl
http://www.mindswap.org/2004/owl-s/1.1/BabelFishTranslator.owl
得到运行结果：
Reading http://www.mindswap.org/2004/owl-s/1.1/BNPrice.owl
Reading http://www.mindswap.org/2004/owl-s/1.1/BookFinder.owl
Reading http://www.mindswap.org/2004/owl-s/1.1/CurrencyConverter.owl
Reading http://www.mindswap.org/2004/owl-s/1.1/Dictionary.owl
Reading http://www.mindswap.org/2004/owl-s/1.1/ZipCodeFinder.owl
Reading http://www.mindswap.org/2004/owl-s/1.1/FindLatLong.owl
Reading http://www.mindswap.org/2004/owl-s/1.1/BabelFishTranslator.owl#
Computing matches...
Matches:
EXACT BNPriceService.BookPrice -> CurrencyConverterService.InputPrice
EXACT BookFinderService.BookInfo -> BNPriceService.BookInfo
EXACT CurrencyConverterService.OutputPrice -> CurrencyConverterService.InputPrice
EXACT DictionaryService.OutputString -> BookFinderService.BookName
EXACT DictionaryService.OutputString -> DictionaryService.InputString
EXACT DictionaryService.OutputString -> ZipCodeFinderService.City
EXACT DictionaryService.OutputString -> ZipCodeFinderService.State
EXACT DictionaryService.OutputString -> BabelFishTranslatorService.InputString
EXACT ZipCodeFinderService.ZipCode -> FindLatLongService.ZipCode
EXACT BabelFishTranslatorService.OutputString -> BookFinderService.BookName
EXACT BabelFishTranslatorService.OutputString -> DictionaryService.InputString
EXACT BabelFishTranslatorService.OutputString -> ZipCodeFinderService.City
EXACT BabelFishTranslatorService.OutputString -> ZipCodeFinderService.State
EXACT BabelFishTranslatorService.OutputString -> BabelFishTranslatorService.InputString
完整代码如下：
import java.io.FileNotFoundException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.mindswap.owl.OWLFactory;
import org.mindswap.owl.OWLIndividual;
import org.mindswap.owl.OWLKnowledgeBase;
import org.mindswap.owl.OWLType;
import org.mindswap.owls.process.Input;
import org.mindswap.owls.process.Output;
import org.mindswap.owls.service.Service;
import org.mindswap.query.ValueMap;
/**
* An example that finds service matches for composition. The outputs of services are matched with
* the inputs of services using one of EXACT, SUBSUME and RELAXED match criteria. Pellet reasoner is
* used to find matches but can be replaced with any other reasoner.
*
* @author Evren Sirin
*/
public class Matchmaker {
OWLKnowledgeBase kb;
public static class Match {
public static String[] MATCHES = {"EXACT", "SUBSUME", "RELAXED", "FAIL"};
public static int EXACT = 0;
public static int SUBSUME = 1;
public static int RELAXED = 2;
public static int FAIL = 3;
int matchType;
boolean listMatch;
Service outputService;
Output output;
Service inputService;
Input input;
public Match(int matchType, Output output, Input input) {
this.matchType = matchType;
this.outputService = output.getService();
this.output = output;
this.inputService = input.getService();
this.input = input;
}
public String toString() {
String str = "";
str += MATCHES[matchType] + " ";
if(listMatch)
str += ".LIST";
str += outputService.getLocalName() + "." + output.getLocalName();
str += " -> ";
str += inputService.getLocalName() + "." + input.getLocalName();
return str;
}
}
public Matchmaker() {
kb = OWLFactory.createKB();
kb.setReasoner("Pellet");
}
public void addOntology( String ont ) throws FileNotFoundException, URISyntaxException {
System.out.println( "Reading " + ont );
kb.read( new URI( ont ) );
}
public void addOntology( URI ont ) throws FileNotFoundException {
System.out.println( "Reading " + ont );
kb.read( ont );
}
public List findServices(boolean getProducers) {
String hasParameter = getProducers ? "process:hasOutput" : "process:hasInput";
String queryString =
"SELECT * " +
"WHERE " +
" (?process rdf:type process:Process)" +
" (?process " + hasParameter + " ?param)" +
"USING " +
" process FOR <http://www.daml.org/services/owl-s/1.1/Process.owl#>";
return kb.query( queryString );
}
public List findOutputs() {
return findServices(true);
}
public List findInputs() {
return findServices(false);
}
public int getMatchType(OWLType outputType, OWLType inputType) {
if(outputType.isEquivalent(inputType))
return Match.EXACT;
else if(outputType.isSubTypeOf(inputType))
return Match.SUBSUME;
else if(inputType.isSubTypeOf(outputType))
return Match.RELAXED;
else
return Match.FAIL;
}
public List displayAllMatches() {
List matches = new ArrayList();
System.out.println( "Computing matches..." );
List producers = findOutputs();
List consumers = findInputs();
Iterator i = producers.iterator();
while( i.hasNext() ) {
ValueMap binding = (ValueMap) i.next();
Output output = (Output) ((OWLIndividual) binding.getValue("param")).castTo(Output.class);
OWLType outputType = output.getParamType();
Iterator j = consumers.iterator();
while( j.hasNext() ) {
binding = (ValueMap) j.next() ;
Input input = (Input) ((OWLIndividual) binding.getValue("param")).castTo(Input.class);
OWLType inputType = input.getParamType();
// System.out.println("Trying " +
// URIUtils.getLocalName(outputType.getURI()) + " " +
// URIUtils.getLocalName(inputType.getURI()) + " " +
// producer.getLocalName() + " " +
// output.getLocalName() + " " +
// consumer.getLocalName() + " " +
// input.getLocalName()
// );
int matchType = getMatchType(outputType, inputType);
if(matchType != Match.FAIL)
matches.add(new Match(matchType, output, input));
}
}
return matches;
}
public static void printIterator(Iterator i) {
if(i.hasNext()) {
while (i.hasNext())
System.out.println( i.next() );
}
else
System.out.println("<EMPTY>");
System.out.println();
}
public static void main(String[] args) throws FileNotFoundException, URISyntaxException {
Matchmaker matchmaker = new Matchmaker();
matchmaker.addOntology("http://www.mindswap.org/2004/owl-s/1.1/BNPrice.owl");
matchmaker.addOntology("http://www.mindswap.org/2004/owl-s/1.1/BookFinder.owl");
matchmaker.addOntology("http://www.mindswap.org/2004/owl-s/1.1/CurrencyConverter.owl");
matchmaker.addOntology("http://www.mindswap.org/2004/owl-s/1.1/Dictionary.owl");
matchmaker.addOntology("http://www.mindswap.org/2004/owl-s/1.1/ZipCodeFinder.owl");
matchmaker.addOntology("http://www.mindswap.org/2004/owl-s/1.1/FindLatLong.owl");
matchmaker.addOntology("http://www.mindswap.org/2004/owl-s/1.1/BabelFishTranslator.owl#");
List matches = matchmaker.displayAllMatches();
System.out.println();
System.out.println("Matches:");
printIterator(matches.iterator());
}
}
对其他几个类作简单介绍：
OWLSValidator主要是对OWL-S文件的有效性进行检验。
PreconditionCheck说明了服务如何被执行。
OWLSExtensions说明了API包的可扩展性，显示了默认Profile的可以扩充为用户自定义的Profile。
Translator主要是对不同版本的service description进行转换，以保证兼容性。
WSDL2OWLS主要是将WDSL描述的服务自动转化为OWL-S描述。
