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Olaf Hartig
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changed the IFragmentRequestProcessor interface such that such processors can be used for multiple requests now, and separated out Jena-specific code from the base class for such processors
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+267
-161
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5 files changed

+267
-161
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‎src/org/linkeddatafragments/datasource/AbstractJenaBasedRequestProcessorForTriplePatterns.java

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package org.linkeddatafragments.datasource;
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import java.util.regex.Matcher;
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import java.util.regex.Pattern;
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import org.linkeddatafragments.fragments.LinkedDataFragment;
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import org.linkeddatafragments.fragments.tpf.TriplePatternFragmentRequest;
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import org.linkeddatafragments.util.CommonResources;
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import com.hp.hpl.jena.datatypes.TypeMapper;
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import com.hp.hpl.jena.rdf.model.Property;
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import com.hp.hpl.jena.rdf.model.RDFNode;
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import com.hp.hpl.jena.rdf.model.Resource;
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import com.hp.hpl.jena.rdf.model.ResourceFactory;
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/**
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* Base class for implementations of {@link IFragmentRequestProcessor} that
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* process {@link TriplePatternFragmentRequest}s based on the Jena API.
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*
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* @author <a href="http://olafhartig.de">Olaf Hartig</a>
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* @author Ruben Verborgh
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*/
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abstract public class AbstractJenaBasedRequestProcessorForTriplePatterns
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extends AbstractRequestProcessorForTriplePatterns
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{
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abstract static protected class Worker
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extends AbstractRequestProcessorForTriplePatterns.Worker
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{
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public Worker( final TriplePatternFragmentRequest request )
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{
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super( request );
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}
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@Override
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protected LinkedDataFragment createFragment( final String subject,
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final String predicate,
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final String object,
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final long offset,
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final long limit )
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throws IllegalArgumentException
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{
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final Resource s = parseAsResource( subject );
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final Property p = parseAsProperty( predicate );
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final RDFNode o = parseAsNode( object );
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return createFragment( s, p, o, offset, limit );
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}
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abstract protected LinkedDataFragment createFragment(
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final Resource subject,
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final Property predicate,
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final RDFNode object,
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final long offset,
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final long limit )
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throws IllegalArgumentException;
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/**
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* Parses the given value as an RDF resource.
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*
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* @param value the value
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* @return the parsed value, or null if unspecified
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*/
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public Resource parseAsResource( String value )
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{
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RDFNode subject = parseAsNode( value );
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return subject == null || subject instanceof Resource
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? (Resource) subject
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: CommonResources.INVALID_URI;
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}
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/**
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* Parses the given value as an RDF property.
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*
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* @param value the value
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* @return the parsed value, or null if unspecified
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*/
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public Property parseAsProperty( String value )
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{
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RDFNode predicateNode = parseAsNode( value );
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if ( predicateNode instanceof Resource ) {
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final String uri = ( (Resource) predicateNode ).getURI();
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return ResourceFactory.createProperty( uri );
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}
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else if ( predicateNode == null ) {
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return null;
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}
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else {
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return CommonResources.INVALID_URI;
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}
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}
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public final static TypeMapper TYPES = TypeMapper.getInstance();
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public final static Pattern STRINGPATTERN
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= Pattern.compile("^\"(.*)\"(?:@(.*)|\\^\\^<?([^<>]*)>?)?$");
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/**
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* Parses the given value as an RDF node.
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*
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* @param value the value
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* @return the parsed value, or null if unspecified
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*/
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public RDFNode parseAsNode( String value )
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{
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// nothing or empty indicates an unknown
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if ( value == null || value.isEmpty() ) {
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return null;
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}
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// find the kind of entity based on the first character
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char firstChar = value.charAt(0);
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switch ( firstChar )
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{
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// variable or blank node indicates an unknown
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case '?':
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case '_':
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return null;
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// angular brackets indicate a URI
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case '<':
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return ResourceFactory.createResource(
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value.substring(1, value.length() - 1) );
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// quotes indicate a string
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case '"':
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Matcher matcher = STRINGPATTERN.matcher( value );
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if ( matcher.matches() ) {
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String body = matcher.group(1);
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String lang = matcher.group(2);
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String type = matcher.group(3);
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if ( lang != null ) {
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return ResourceFactory.createLangLiteral(
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body, lang );
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}
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else if ( type != null ) {
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return ResourceFactory.createTypedLiteral(
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body, TYPES.getSafeTypeByName(type) );
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}
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else {
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return ResourceFactory.createPlainLiteral( body );
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}
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}
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else {
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return CommonResources.INVALID_URI;
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}
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// assume it's a URI without angular brackets
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default:
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return ResourceFactory.createResource( value );
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}
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}
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} // end of class Worker
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}

‎src/org/linkeddatafragments/datasource/AbstractRequestProcessor.java

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package org.linkeddatafragments.datasource;
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import org.linkeddatafragments.fragments.LinkedDataFragment;
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import org.linkeddatafragments.fragments.LinkedDataFragmentRequest;
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/**
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* Base class for implementations of {@link IFragmentRequestProcessor}.
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*
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* @author <a href="http://olafhartig.de">Olaf Hartig</a>
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*/
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abstract public class AbstractRequestProcessor
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implements IFragmentRequestProcessor
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{
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@Override
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public void close() {}
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@Override
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final public LinkedDataFragment createRequestedFragment(
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final LinkedDataFragmentRequest request )
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throws IllegalArgumentException
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{
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return getWorker( request ).createRequestedFragment();
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}
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abstract protected Worker getWorker(
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final LinkedDataFragmentRequest request )
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throws IllegalArgumentException;
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abstract static protected class Worker
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{
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public final LinkedDataFragmentRequest request;
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public Worker( final LinkedDataFragmentRequest request )
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{
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this.request = request;
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}
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abstract public LinkedDataFragment createRequestedFragment()
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throws IllegalArgumentException;
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} // end of class Worker
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}

‎src/org/linkeddatafragments/datasource/AbstractRequestProcessorForTriplePatterns.java

Lines changed: 63 additions & 58 deletions
Original file line numberDiff line numberDiff line change
@@ -7,82 +7,87 @@
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import org.linkeddatafragments.fragments.tpf.TriplePatternFragmentRequest;
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import com.hp.hpl.jena.rdf.model.Model;
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import com.hp.hpl.jena.rdf.model.Property;
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import com.hp.hpl.jena.rdf.model.RDFNode;
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import com.hp.hpl.jena.rdf.model.Resource;
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/**
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* Base class for implementations of {@link IFragmentRequestProcessor} that
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* process triple pattern based requests.
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* process {@link TriplePatternFragmentRequest}s.
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*
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* @author <a href="http://olafhartig.de">Olaf Hartig</a>
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*/
2017
public abstract class AbstractRequestProcessorForTriplePatterns
21-
implements IFragmentRequestProcessor
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extends AbstractRequestProcessor
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{
23-
public final TriplePatternFragmentRequest request;
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public final long pageNumber;
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public AbstractRequestProcessorForTriplePatterns(
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final TriplePatternFragmentRequest request )
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@Override
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protected Worker getWorker( final LinkedDataFragmentRequest request )
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throws IllegalArgumentException
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{
29-
this.request = request;
30-
if ( request.isPageRequest() )
31-
this.pageNumber = request.getPageNumber();
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if ( request instanceof TriplePatternFragmentRequest )
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return getWorker( (TriplePatternFragmentRequest) request );
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else
33-
this.pageNumber = 1L;
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throw new IllegalArgumentException( request.getClass().getName() );
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}
3529

36-
@Override
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public void close() {}
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abstract protected Worker getWorker(
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final TriplePatternFragmentRequest request )
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throws IllegalArgumentException;
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39-
@Override
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public LinkedDataFragment createRequestedFragment()
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{
42-
final long limit = LinkedDataFragmentRequest.TRIPLESPERPAGE;
43-
final long offset = limit * ( pageNumber - 1L );
4434

45-
return createFragment( request.getSubject(),
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request.getPredicate(),
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request.getObject(),
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offset, limit );
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}
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abstract static protected class Worker
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extends AbstractRequestProcessor.Worker
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{
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public Worker( final TriplePatternFragmentRequest request )
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{
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super( request );
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}
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52-
protected LinkedDataFragment createFragment( final String subj,
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final String pred,
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final String obj,
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final long offset,
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final long limit )
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{
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final Resource s = FragmentRequestProcessorUtils.parseAsResource(subj);
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final Property p = FragmentRequestProcessorUtils.parseAsProperty(pred);
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final RDFNode o = FragmentRequestProcessorUtils.parseAsNode(obj);
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@Override
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public LinkedDataFragment createRequestedFragment()
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throws IllegalArgumentException
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{
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final long limit = LinkedDataFragmentRequest.TRIPLESPERPAGE;
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final long offset;
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if ( request.isPageRequest() )
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offset = limit * ( request.getPageNumber() - 1L );
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else
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offset = 0L; // FIXME: we should not have a limit in this case!
6153

62-
return createFragment( s, p, o, offset, limit );
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}
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final TriplePatternFragmentRequest tpfRequest =
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(TriplePatternFragmentRequest) request;
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65-
abstract protected LinkedDataFragment createFragment( final Resource subject,
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final Property predicate,
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final RDFNode object,
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final long offset,
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final long limit );
57+
return createFragment( tpfRequest.getSubject(),
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tpfRequest.getPredicate(),
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tpfRequest.getObject(),
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offset, limit );
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}
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71-
protected TriplePatternFragment createEmptyTriplePatternFragment()
72-
{
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return new TriplePatternFragmentImpl( request.getFragmentURL(),
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request.getDatasetURL() );
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}
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abstract protected LinkedDataFragment createFragment( final String subj,
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final String pred,
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final String obj,
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final long offset,
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final long limit )
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throws IllegalArgumentException;
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77-
protected TriplePatternFragment createTriplePatternFragment(
78-
Model triples, long totalSize, final boolean isLastPage )
79-
{
80-
return new TriplePatternFragmentImpl( triples,
81-
totalSize,
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request.getFragmentURL(),
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request.getDatasetURL(),
84-
pageNumber,
85-
isLastPage );
86-
}
70+
protected TriplePatternFragment createEmptyTriplePatternFragment()
71+
{
72+
return new TriplePatternFragmentImpl( request.getFragmentURL(),
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request.getDatasetURL() );
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}
75+
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protected TriplePatternFragment createTriplePatternFragment(
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final Model triples,
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final long totalSize,
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final boolean isLastPage )
80+
{
81+
// FIXME: deal with the case in which request.isPageRequest()==false
82+
83+
return new TriplePatternFragmentImpl( triples,
84+
totalSize,
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request.getFragmentURL(),
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request.getDatasetURL(),
87+
request.getPageNumber(),
88+
isLastPage );
89+
}
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} // end of class Worker
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}

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