Custom File Filter Null Extension Fixes (#447)

Provide string utility method with guaranteed contract to return false instead of an NPE for null strings and suffixes. Prevent null extensions from being accepted in the custom file filter constructor.

org/lateralgm/components/impl/CustomFileFilter.java

@@ -15,6 +15,8 @@
 
 import javax.swing.filechooser.FileFilter;
 
+import org.lateralgm.main.Util;
+
 public class CustomFileFilter extends FileFilter implements FilenameFilter
 	{
 	private ArrayList<String> ext = new ArrayList<String>();
@@ -36,7 +38,7 @@ public CustomFileFilter(String desc, String...ext)
 		{
 		this.desc = desc;
 		for (String element : ext)
-			this.ext.add(element);
+			if (element != null) this.ext.add(element);
 		}
 
 	public boolean accept(File f)
@@ -50,7 +52,7 @@ public boolean accept(File dir, String name)
 		if (ext.size() == 0) return true;
 		//if (f.isDirectory()) return true;
 		for (String e : ext)
-			if (name.endsWith(e))
+			if (Util.stringEndsWith(name,e))
 				return true;
 		return false;
 		}

org/lateralgm/main/LGM.java

@@ -135,7 +135,7 @@
 
 public final class LGM
 	{
-	public static final String version = "1.8.82"; //$NON-NLS-1$
+	public static final String version = "1.8.83"; //$NON-NLS-1$
 
 	// TODO: This list holds the class loader for any loaded plugins which should be
 	// cleaned up and closed when the application closes.

org/lateralgm/main/Util.java

@@ -1255,4 +1255,11 @@ public static void OpenDesktopEditor(File file)
 					JOptionPane.ERROR_MESSAGE);
 			}
 		}
+
+	// Guaranteed contract to not throw an NPE and return false if str or suffix is null.
+	public static boolean stringEndsWith(String str, String suffix)
+		{
+		if (suffix == null || str == null) return false;
+		return str.endsWith(suffix);
+		}
 	}