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Commit 693f9b1

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author
Olaf Hartig
committed
changed the existing code base to use the new i'faces and classes for LDF requests and for processors of such requests
1 parent 1400984 commit 693f9b1

7 files changed

Lines changed: 139 additions & 335 deletions

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‎src/org/linkeddatafragments/datasource/DataSource.java‎

Lines changed: 0 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -8,20 +8,6 @@
88
public abstract class DataSource implements IDataSource {
99
protected String title;
1010
protected String description;
11-
12-
/**
13-
*
14-
* @param offset
15-
* @param limit
16-
*/
17-
protected void checkBoundaries(long offset, long limit) {
18-
if (offset < 0) {
19-
throw new IndexOutOfBoundsException("offset");
20-
}
21-
if (limit < 1) {
22-
throw new IllegalArgumentException("limit");
23-
}
24-
}
2511

2612
public DataSource(String title, String description) {
2713
this.title = title;

‎src/org/linkeddatafragments/datasource/HdtDataSource.java‎

Lines changed: 27 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -20,6 +20,7 @@
2020
* An HDT data source of Basic Linked Data Fragments.
2121
*
2222
* @author Ruben Verborgh
23+
* @author <a href="http://olafhartig.de">Olaf Hartig</a>
2324
*/
2425
public class HdtDataSource extends DataSource {
2526

@@ -41,16 +42,35 @@ public HdtDataSource(String title, String description, String hdtFile) throws IO
4142
}
4243

4344
@Override
44-
public TriplePatternFragment getFragment(Resource subject, Property predicate, RDFNode object, final long offset, final long limit) {
45-
checkBoundaries(offset, limit);
45+
public IFragmentRequestProcessor getRequestProcessor(
46+
final LinkedDataFragmentRequest request )
47+
{
48+
if ( ! (request instanceof TriplePatternFragmentRequest) )
49+
throw new IllegalArgumentException();
4650

51+
return new MyProcessor( (TriplePatternFragmentRequest) request );
52+
}
53+
54+
protected class MyProcessor extends AbstractRequestProcessorForTriplePatterns
55+
{
56+
public MyProcessor( final TriplePatternFragmentRequest request ) {
57+
super( request );
58+
}
59+
60+
@Override
61+
protected LinkedDataFragment createFragment( final Resource subject,
62+
final Property predicate,
63+
final RDFNode object,
64+
final long offset,
65+
final long limit )
66+
{
4767
// look up the result from the HDT datasource)
4868
int subjectId = subject == null ? 0 : dictionary.getIntID(subject.asNode(), TripleComponentRole.SUBJECT);
4969
int predicateId = predicate == null ? 0 : dictionary.getIntID(predicate.asNode(), TripleComponentRole.PREDICATE);
5070
int objectId = object == null ? 0 : dictionary.getIntID(object.asNode(), TripleComponentRole.OBJECT);
5171

5272
if (subjectId < 0 || predicateId < 0 || objectId < 0) {
53-
return new TriplePatternFragmentBase();
73+
return createEmptyTriplePatternFragment();
5474
}
5575

5676
final Model triples = ModelFactory.createDefaultModel();
@@ -92,19 +112,12 @@ public TriplePatternFragment getFragment(Resource subject, Property predicate, R
92112
: 0;
93113

94114
// create the fragment
95-
return new TriplePatternFragment() {
96-
@Override
97-
public Model getTriples() {
98-
return triples;
99-
}
100-
101-
@Override
102-
public long getTotalSize() {
103-
return estimatedTotal;
104-
}
105-
};
115+
final boolean isLastPage = ( estimatedTotal < offset + limit );
116+
return createTriplePatternFragment( triples, estimatedTotal, isLastPage );
106117
}
107118

119+
} // end of MyProcessor
120+
108121
/**
109122
* Converts the HDT triple to a Jena Triple.
110123
*

‎src/org/linkeddatafragments/datasource/IDataSource.java‎

Lines changed: 11 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -2,27 +2,22 @@
22

33
import java.io.Closeable;
44

5-
import com.hp.hpl.jena.rdf.model.Property;
6-
import com.hp.hpl.jena.rdf.model.RDFNode;
7-
import com.hp.hpl.jena.rdf.model.Resource;
8-
95
/**
10-
* A data source of Basic Linked Data Fragments.
6+
* A data source of Linked Data Fragments.
7+
*
118
* @author Ruben Verborgh
9+
* @author <a href="http://olafhartig.de">Olaf Hartig</a>
1210
*/
1311
public interface IDataSource extends Closeable {
14-
/**
15-
* Gets a page of the Basic Linked Data Fragment matching the specified triple pattern.
16-
* @param subject the subject (null to match any subject)
17-
* @param predicate the predicate (null to match any predicate)
18-
* @param object the object (null to match any object)
19-
* @param offset the triple index at which to start the page
20-
* @param limit the number of triples on the page
21-
* @return the first page of the fragment
22-
*/
23-
public TriplePatternFragment getFragment(Resource subject, Property predicate,
24-
RDFNode object, long offset, long limit);
12+
2513
public String getTitle();
2614

2715
public String getDescription();
16+
17+
/**
18+
* Returns a data source specific processor for the given request of a
19+
* Linked Data Fragment.
20+
*/
21+
IFragmentRequestProcessor getRequestProcessor(
22+
final LinkedDataFragmentRequest request );
2823
}

‎src/org/linkeddatafragments/datasource/IndexDataSource.java‎

Lines changed: 28 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -15,6 +15,7 @@
1515
* An Index data source provides an overview of all available datasets.
1616
*
1717
* @author Miel Vander Sande
18+
* @author <a href="http://olafhartig.de">Olaf Hartig</a>
1819
*/
1920
public class IndexDataSource extends DataSource {
2021

@@ -44,8 +45,29 @@ public IndexDataSource(String baseUrl, HashMap<String, IDataSource> datasources)
4445
}
4546

4647
@Override
47-
public TriplePatternFragment getFragment(Resource subject, Property predicate, RDFNode object, long offset, long limit) {
48-
StmtIterator listStatements = this.model.listStatements(subject, predicate, object);
48+
public IFragmentRequestProcessor getRequestProcessor(
49+
final LinkedDataFragmentRequest request )
50+
{
51+
if ( ! (request instanceof TriplePatternFragmentRequest) )
52+
throw new IllegalArgumentException();
53+
54+
return new MyProcessor( (TriplePatternFragmentRequest) request );
55+
}
56+
57+
protected class MyProcessor extends AbstractRequestProcessorForTriplePatterns
58+
{
59+
public MyProcessor( final TriplePatternFragmentRequest request ) {
60+
super( request );
61+
}
62+
63+
@Override
64+
protected LinkedDataFragment createFragment( final Resource subject,
65+
final Property predicate,
66+
final RDFNode object,
67+
final long offset,
68+
final long limit )
69+
{
70+
StmtIterator listStatements = model.listStatements(subject, predicate, object);
4971
Model result = ModelFactory.createDefaultModel();
5072

5173
long index = 0;
@@ -58,7 +80,10 @@ public TriplePatternFragment getFragment(Resource subject, Property predicate, R
5880
result.add(listStatements.next());
5981
}
6082

61-
return new TriplePatternFragmentBase(result, result.size());
83+
final boolean isLastPage = ( result.size() < offset + limit );
84+
return createTriplePatternFragment( result, result.size(), isLastPage );
6285
}
6386

87+
} // end of MyProcessor
88+
6489
}

‎src/org/linkeddatafragments/datasource/JenaTDBDataSource.java‎

Lines changed: 29 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -22,6 +22,7 @@
2222
* Experimental Jena TDB-backed data source of Basic Linked Data Fragments.
2323
*
2424
* @author Bart Hanssens <bart.hanssens@fedict.be>
25+
* @author <a href="http://olafhartig.de">Olaf Hartig</a>
2526
*/
2627
public class JenaTDBDataSource extends DataSource {
2728
private final Dataset tdb;
@@ -34,9 +35,28 @@ public class JenaTDBDataSource extends DataSource {
3435
private final Query countQuery = QueryFactory.create(count, Syntax.syntaxSPARQL_11);
3536

3637
@Override
37-
public TriplePatternFragment getFragment(Resource subject, Property predicate, RDFNode object, long offset, long limit) {
38-
checkBoundaries(offset, limit);
38+
public IFragmentRequestProcessor getRequestProcessor(
39+
final LinkedDataFragmentRequest request )
40+
{
41+
if ( ! (request instanceof TriplePatternFragmentRequest) )
42+
throw new IllegalArgumentException();
3943

44+
return new MyProcessor( (TriplePatternFragmentRequest) request );
45+
}
46+
47+
protected class MyProcessor extends AbstractRequestProcessorForTriplePatterns
48+
{
49+
public MyProcessor( final TriplePatternFragmentRequest request ) {
50+
super( request );
51+
}
52+
53+
@Override
54+
protected LinkedDataFragment createFragment( final Resource subject,
55+
final Property predicate,
56+
final RDFNode object,
57+
final long offset,
58+
final long limit )
59+
{
4060
Model model = tdb.getDefaultModel();
4161
QuerySolutionMap map = new QuerySolutionMap();
4262
if (subject != null) {
@@ -59,7 +79,7 @@ public TriplePatternFragment getFragment(Resource subject, Property predicate, R
5979
}
6080

6181
if (triples.isEmpty()) {
62-
return new TriplePatternFragmentBase();
82+
return createEmptyTriplePatternFragment();
6383
}
6484

6585
// Try to get an estimate
@@ -87,9 +107,14 @@ public TriplePatternFragment getFragment(Resource subject, Property predicate, R
87107
if (estimate < offset + size) {
88108
estimate = (size == limit) ? offset + size + 1 : offset + size;
89109
}
90-
return new TriplePatternFragmentBase(triples, estimate);
110+
111+
// create the fragment
112+
final boolean isLastPage = ( estimate < offset + limit );
113+
return createTriplePatternFragment( triples, estimate, isLastPage );
91114
}
92115

116+
} // end of MyProcessor
117+
93118

94119
/**
95120
* Constructor

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