From 205cdc4559c5713441cb1529c18a25be4a639d3e Mon Sep 17 00:00:00 2001
From: Stefan Hahmann <stefan.hahmann@tu-dresden.de>
Date: Tue, 28 May 2024 18:11:24 +0200
Subject: [PATCH] Make file filter show the extension, instead of cryptic stuff

* Override FileFilter toString() method in SwingFileWidget so that it shows the extension(s) that are filtered by the file choose dialog instead of the standard toString() of the
* Related to
  * https://github.com/bigdataviewer/bigdataviewer-playground/issues/110
  * https://forum.image.sc/t/scijava-command-file-extensions/29869/2
---
 .../ui/swing/widget/SwingFileWidget.java      | 16 ++++++++++++++
 .../ui/swing/widget/SwingFileWidgetTest.java  | 21 +++++++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 src/test/java/org/scijava/ui/swing/widget/SwingFileWidgetTest.java

diff --git a/src/main/java/org/scijava/ui/swing/widget/SwingFileWidget.java b/src/main/java/org/scijava/ui/swing/widget/SwingFileWidget.java
index f669e39..224f593 100644
--- a/src/main/java/org/scijava/ui/swing/widget/SwingFileWidget.java
+++ b/src/main/java/org/scijava/ui/swing/widget/SwingFileWidget.java
@@ -40,6 +40,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.StringJoiner;
 import java.util.stream.Collectors;
 
 import javax.swing.Box;
@@ -235,9 +236,24 @@ public boolean accept(final File pathname) {
 				}
 				return false;
 			}
+
+			@Override
+			public String toString() {
+				return formatFileFilterExtensions( exts );
+			}
 		};
 	}
 
+	static String formatFileFilterExtensions( final List< String > extensions ) {
+		List< String > extsWithPrefix = new ArrayList<>();
+		for ( String extension : extensions ) {
+			extsWithPrefix.add( "*." + extension );
+		}
+		StringJoiner joiner = new StringJoiner( ";" );
+		extsWithPrefix.forEach( joiner::add );
+		return joiner.toString();
+	}
+
 	/**
 	 * Checks whether the given drag and drop operation offers a list of files as
 	 * one of its flavors.
diff --git a/src/test/java/org/scijava/ui/swing/widget/SwingFileWidgetTest.java b/src/test/java/org/scijava/ui/swing/widget/SwingFileWidgetTest.java
new file mode 100644
index 0000000..d03a797
--- /dev/null
+++ b/src/test/java/org/scijava/ui/swing/widget/SwingFileWidgetTest.java
@@ -0,0 +1,21 @@
+package org.scijava.ui.swing.widget;
+
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+
+public class SwingFileWidgetTest
+{
+
+	@Test
+	public void testFormatFileFilterExtensions() {
+		final List< String > multipleExtensions = Arrays.asList( "jpg", "jpeg", "png", "gif", "bmp" );
+		final List< String > singleExtension = Collections.singletonList( "xml" );
+		assertEquals( "*.jpg;*.jpeg;*.png;*.gif;*.bmp", SwingFileWidget.formatFileFilterExtensions( multipleExtensions ) );
+		assertEquals( "*.xml", SwingFileWidget.formatFileFilterExtensions( singleExtension ) );
+	}
+}