[SIS-178] First property read in a DenseFeature returns a null value, next ones are ok.

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.5
• Fix Version/s: 0.5
• Component/s: Features

Environment

Seen on branch JDK 8, but should be the same everywhere.

• Assignee: Martin Desruisseaux
• Reporter: Marc Le Bihan
• Created: 29/Sep/14 14:27
• Updated: 03/Feb/15 21:39
• Resolved: 03/Feb/15 21:39

Description

The first field value asked in a DenseFeature is always returning a null value, the next calls on the same feature are successful.

Loading a sample shapefile from here
http://export.openstreetmap.fr/contours-administratifs/communes/92-Hauts-de-Seine.shp.tar.gz

If I attempt to query the values of a Feature this way : "REF_INSEE", "COMMUNE", "CODE_POSTA",
I will receive : null, “a city name”, “a zip code”.

If I try to query this way : "CODE_POSTA", "REF_INSEE", "COMMUNE",
I will receive : null, “an INSEE code”, “a city name”.

Involved method :

DenseFeature.java

@Override
public Property getProperty(final String name) throws IllegalArgumentException {
    ArgumentChecks.ensureNonNull("name", name);
    final int index = getIndex(name);
    if (properties instanceof Property[]) {
        final Property property = ((Property[]) properties)[index];
        if (property != null) {
            return property;
        }
    } else {
        wrapValuesInProperties();
    }
    final Property property = createProperty(name);
    properties[index] = property;
    return property;
}

hypothesis :
after the init call of

wrapValuesInProperties();

the method assumes that it has done the same work it would have done with

final Property property = ((Property[]) properties)[index];

but it’s not the case.

The following unit test will show the problem :

IssuesWithFeaturesTest.java

package org.apache.sis.storage.shapefile;

import static org.junit.Assert.*;

import java.io.*;

import org.apache.sis.storage.*;
import org.junit.*;
import org.opengis.feature.*;
import org.opengis.test.*;

/**
 * Issues with features.
 */
public class IssuesWithFeaturesTest extends TestCase
{
   /**
    * Issue : the first property red by DenseFeature is null.
    * @throws DataStoreException if unable to find or read the shapefile.
    * @throws IOException if unable to find or read the shapefile.
    */
   @Test public void issueFirstPropertyNull() throws IOException, DataStoreException {
      ShapeFile shapefile = new ShapeFile("src/test/resources/org/apache/sis/storage/shapefile/92-Hauts-de-Seine.shp");

      Feature feature = shapefile.FeatureMap.values().iterator().next(); // The shapefile has 36 features, take the first one.
      String city = (String)feature.getProperty("COMMUNE\0\0\0\0").getValue();
      String refInsee = (String)feature.getProperty("REF_INSEE\0\0").getValue();
      String zipCode = (String)feature.getProperty("CODE_POSTA\0").getValue();

      // The first feature property you read (city here) will return a null value.
      assertNotNull("The city should have an INSEE reference.", refInsee);
      assertNotNull("The city should have a zip code.", zipCode);
      assertNotNull("The city should have a name.", city);
   }
}