Add meaningful error when no images could be found in a table

src/main/java/org/embl/mobie/lib/SourcesFromTableCreator.java

@@ -44,9 +44,8 @@
 import tech.tablesaw.columns.Column;
 
 import java.io.File;
-import java.util.ArrayList;
-import java.util.LinkedHashSet;
-import java.util.List;
+import java.lang.reflect.Array;
+import java.util.*;
 
 import static tech.tablesaw.aggregate.AggregateFunctions.mean;
 
@@ -103,8 +102,12 @@ public SourcesFromTableCreator( String tablePath, List< String > imageColumns, L
 			}
 		}
 
+
 		// region table for grid view
 		//
+		if ( imageFileSources.isEmpty() )
+			throw new RuntimeException("No images found in the table! Please check your table and image column names: " + imageColumns );
+
 		int numSources = imageFileSources.get( 0 ).getSources().size();
 
 		if ( table.rowCount() == numSources )
@@ -126,14 +129,15 @@ public SourcesFromTableCreator( String tablePath, List< String > imageColumns, L
 			regionTable = Table.create( "image table" );
 
 			// init columns
-			LinkedHashSet< String > uniqueImagePaths = new LinkedHashSet<>(); // important not to change the order!
+			LinkedHashSet< String > uniqueRegionNames = new LinkedHashSet<>(); // important not to change the order!
 			String imageColumnName = new TableImageSource( imageColumns.get( 0 ) ).columnName;
 			StringColumn imageColumn = table.stringColumn( imageColumnName );
 			for ( String imagePath : imageColumn )
 			{
-				uniqueImagePaths.add( imagePath );
+				// FIXME It would be nice to shorten the names, e.g. by removing everything that is common to all image paths
+				uniqueRegionNames.add( imagePath );
 			}
-			final List< String > regions = new ArrayList<>( uniqueImagePaths );
+			final List< String > regions = new ArrayList<>( uniqueRegionNames );
 			regionTable.addColumns( StringColumn.create( ColumnNames.REGION_ID, regions ) ); // needed for region table
 			regionTable.addColumns( StringColumn.create( imageColumnName, regions ) ); // needed for joining the tables
 

src/test/java/projects/OpenRemoteAlexandraTable.java

@@ -0,0 +1,53 @@
+/*-
+ * #%L
+ * Fiji viewer for MoBIE projects
+ * %%
+ * Copyright (C) 2018 - 2024 EMBL
+ * %%
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ * #L%
+ */
+package projects;
+
+import net.imagej.ImageJ;
+import org.embl.mobie.MoBIE;
+import org.embl.mobie.MoBIESettings;
+import org.embl.mobie.command.open.OpenTableCommand;
+import org.embl.mobie.lib.transform.GridType;
+
+import java.io.File;
+import java.io.IOException;
+
+public class OpenRemoteAlexandraTable
+{
+	public static void main( String[] args ) throws IOException
+	{
+		final ImageJ imageJ = new ImageJ();
+		imageJ.ui().showUI();
+
+		OpenTableCommand command = new OpenTableCommand();
+		command.table = new File("/Users/tischer/Desktop/alexandra-mobie.tsv");
+		command.gridType = GridType.Transformed;
+		command.images = "Images";
+		command.run();
+	}
+}