eclipse-rdf4jGH-5058: additional parser code (WIP)

Fedict · Jul 15, 2024 · 489756f · 489756f
1 parent 2b1d57f
commit 489756f
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Showing 2 changed files with 74 additions and 19 deletions.
diff --git a/core/rio/csvw/src/main/java/org/eclipse/rdf4j/rio/csvw/CSVWParser.java b/core/rio/csvw/src/main/java/org/eclipse/rdf4j/rio/csvw/CSVWParser.java
@@ -24,7 +24,6 @@
 import java.util.Optional;
 import java.util.stream.Collectors;
 
-import org.apache.commons.lang3.CharSet;
 import org.eclipse.rdf4j.model.BNode;
 import org.eclipse.rdf4j.model.IRI;
 import org.eclipse.rdf4j.model.Model;
@@ -48,6 +47,7 @@
 import org.eclipse.rdf4j.rio.csvw.parsers.CellParser;
 import org.eclipse.rdf4j.rio.csvw.parsers.CellParserFactory;
 import org.eclipse.rdf4j.rio.helpers.AbstractRDFParser;
+
 import org.slf4j.LoggerFactory;
 
 import com.opencsv.CSVParser;
@@ -57,14 +57,17 @@
 import com.opencsv.exceptions.CsvValidationException;
 
 /**
- * Basic (experimental) CSV on the Web parser.
- *
- * Currently only "minimal mode" is supported
+ * Experimental CSV on the Web parser.
  *
  * @author Bart Hanssens
  *
+ * Basically it consists of an existing CSV file and a metadata file (in JSON-LD) describing the columns.
+ * Parsers need to convert the data client-side.
+ * 
  * @see <a href="https://w3c.github.io/csvw/primer/">CSV on the Web Primer</a>
+ * @see <a href="https://w3c.github.io/csvw/syntax/">Model for Tabular Data and Metadata on the Web</a>
  * @see <a href="https://w3c.github.io/csvw/metadata">Metadata Vocabulary for Tabular Data</a>
+ * 
  * @since 5.1.0
  */
 public class CSVWParser extends AbstractRDFParser {
@@ -86,7 +89,7 @@ public synchronized void parse(InputStream in, String baseURI)
 			throw new RDFParseException("No metadata found");
 		}
 
-		RDFHandler rdfHandler = getRDFHandler();
+		rdfHandler = getRDFHandler();
 
 		boolean minimal = getParserConfig().get(CSVWParserSettings.MINIMAL_MODE);
 		Resource rootNode = minimal ? null : generateTablegroupNode(rdfHandler);

diff --git a/core/rio/csvw/src/main/java/org/eclipse/rdf4j/rio/csvw/parsers/CellParser.java b/core/rio/csvw/src/main/java/org/eclipse/rdf4j/rio/csvw/parsers/CellParser.java
@@ -10,7 +10,10 @@
  *******************************************************************************/
 package org.eclipse.rdf4j.rio.csvw.parsers;
 
+import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
+import java.util.HashSet;
 import java.util.Set;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -29,6 +32,7 @@ public abstract class CellParser {
 	private static final Pattern PLACEHOLDERS = Pattern.compile("(\\{#?_?[^\\}]+\\})");
 
 	private String name;
+	private String encodedName;
 	private IRI dataType;
 	private String lang;
 	private String defaultValue;
@@ -45,18 +49,45 @@ public abstract class CellParser {
 	private boolean virtual = false;
 	private boolean suppressed = false;
 
+	private String aboutPlaceholder;
 	private String[] aboutPlaceholders;
-	private String[] propPlaceholders;
-	private String[] valPlaceholders;
+
+	private String valuePlaceholder;
+	private String[] valuePlaceholders;
 
+	/**
+	 * Get name of the column
+	 * 
+	 * @return 
+	 */
 	public String getName() {
 		return name;
 	}
 
+	/**
+	 * Get URL encoded name
+	 * 
+	 * @return encoded name 
+	 */
+	public String getNameEncoded() {
+		return encodedName;
+	}
+
+	/**
+	 * Set name of the column
+	 * 
+	 * @param name 
+	 */
 	public void setName(String name) {
 		this.name = name;
+		this.encodedName = URLEncoder.encode(name, StandardCharsets.UTF_8);
 	}
-
+
+	/**
+	 * Get datatype
+	 * 
+	 * @return 
+	 */
 	public IRI getDataType() {
 		return dataType;
 	}
@@ -135,21 +166,39 @@ public void setVirtual(boolean virtual) {
 		this.virtual = virtual;
 	}
 
+
 	/**
-	 * Extract placeholders (if any)
+	 * Extract placeholder name for the own column, if any
 	 *
 	 * @param template URI template string
-	 * @return array of placeholders
+	 * @return placeholder name or null
 	 */
-	private String[] extractPlaceholders(String template) {
+	private String getOwnPlaceholder(String template) {
+		if (encodedName != null) {
+			String placeholder = "{" + encodedName + "}";
+			if (template.contains(placeholder)) {
+				return placeholder;
+			}
+		}
+		return null;
+	}
+
+	/**
+	 * Extract placeholder names for (values of) other columns, if any
+	 *
+	 * @param template URI template string
+	 * @return array of placeholder names
+	 */
+	private String[] getPlaceholders(String template) {
 		Matcher matcher = PLACEHOLDERS.matcher(template);
+		String ownPlaceholder = getOwnPlaceholder(template);
+
 		if (matcher.find()) {
-			int matches = matcher.groupCount();
-			String[] placeholders = new String[matches];
-			for (int i = 0; i < matches; i++) {
-				placeholders[i] = matcher.group(i + 1);
-			}
-			return placeholders;
+			Set<String> placeholders = matcher.results()
+										.map(m -> m.group())
+										.filter(m -> !m.equals(ownPlaceholder))
+										.collect(Collectors.toSet());
+			return placeholders.toArray(new String[placeholders.size()]);
 		}
 		return null;
 	}
@@ -170,7 +219,9 @@ public String getAboutUrl() {
 	 */
 	public void setAboutUrl(String aboutUrl) {
 		this.aboutUrl = aboutUrl;
-		this.aboutPlaceholders = extractPlaceholders(aboutUrl);
+		// check if this URL contains column placeholders
+		this.aboutPlaceholder = getOwnPlaceholder(aboutUrl);
+		this.aboutPlaceholders = getPlaceholders(aboutUrl);
 	}
 
 	/**
@@ -217,7 +268,8 @@ public String getValueUrl() {
 	 */
 	public void setValueUrl(String valueUrl) {
 		this.valueUrl = valueUrl;
-		this.valPlaceholders = extractPlaceholders(valueUrl);
+		// check if this URL contains column placeholders
+		this.valuePlaceholders = getPlaceholders(valueUrl);
 	}
 
 	/**