Fix #268 Make sure license file name has only one extension

src/it/download-licenses-basic/expected_licenses_ordering_1.xml

@@ -23,7 +23,7 @@
           <name>New BSD License</name>
           <url>http://www.opensource.org/licenses/bsd-license.php</url>
           <distribution>repo</distribution>
-          <file>new bsd license - bsd-license.php.html</file>
+          <file>new bsd license - bsd-license.html</file>
         </license>
       </licenses>
     </dependency>

src/it/download-licenses-basic/expected_licenses_ordering_2.xml

@@ -10,7 +10,7 @@
           <name>New BSD License</name>
           <url>http://www.opensource.org/licenses/bsd-license.php</url>
           <distribution>repo</distribution>
-          <file>new bsd license - bsd-license.php.html</file>
+          <file>new bsd license - bsd-license.html</file>
         </license>
       </licenses>
     </dependency>

src/main/java/org/codehaus/mojo/license/download/LicenseDownloader.java

@@ -79,6 +79,8 @@ public class LicenseDownloader implements AutoCloseable
      */
     public static final int DEFAULT_CONNECTION_TIMEOUT = 5000;
 
+    private static final Pattern EXTENSION_PATTERN = Pattern.compile( "\\.[a-z]{1,4}$", Pattern.CASE_INSENSITIVE );
+
     private final CloseableHttpClient client;
 
     public LicenseDownloader( Proxy proxy )
@@ -232,23 +234,20 @@ public LicenseDownloadResult downloadLicense( String licenseUrlString, FileNameE
         }
     }
 
-    private static File updateFileExtension( File outputFile, String mimeType )
+    static File updateFileExtension( File outputFile, String mimeType )
     {
-        final String realExtension = FileUtil.toExtension( mimeType, false );
-
-        if ( realExtension != null )
+        String realExtension = FileUtil.toExtension( mimeType, false );
+        if ( realExtension == null )
         {
-            if ( !outputFile.getName().endsWith( realExtension ) )
-            {
-                return new File( outputFile.getAbsolutePath() + realExtension );
-            }
+            /* default extension is .txt */
+            realExtension = ".txt";
         }
-        /* default extension is .txt */
-        final String name = outputFile.getName();
-        final int periodPos = name.lastIndexOf( '.' );
-        if ( periodPos < 0 || name.length() - periodPos > 5 )
+
+        final String oldFileName = outputFile.getName();
+        if ( !oldFileName.endsWith( realExtension ) )
         {
-            return new File( outputFile.getParent(), name.substring( 0, periodPos ) + ".txt" );
+            final String newFileName = EXTENSION_PATTERN.matcher( oldFileName ).replaceAll( "" ) + realExtension;
+            return new File( outputFile.getParentFile(), newFileName );
         }
         return outputFile;
     }

src/test/java/org/codehaus/mojo/license/download/LicenseDownloaderTest.java

@@ -0,0 +1,46 @@
+package org.codehaus.mojo.license.download;
+
+/*
+ * #%L
+ * License Maven Plugin
+ * %%
+ * Copyright (C) 2019 Codehaus
+ * %%
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Lesser Public License for more details.
+ *
+ * You should have received a copy of the GNU General Lesser Public
+ * License along with this program.  If not, see
+ * <http://www.gnu.org/licenses/lgpl-3.0.html>.
+ * #L%
+ */
+
+import java.io.File;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class LicenseDownloaderTest
+{
+
+    @Test
+    public void updateFileExtension() {
+        assertExtension( "path/to/file.html", "path/to/file.php", "text/html" );
+        assertExtension( "path/to/file.txt", "path/to/file", null );
+    }
+
+    private static void assertExtension( String expected, String input, String mimeType )
+    {
+        final File in = new File( input );
+        final File result = LicenseDownloader.updateFileExtension( in, mimeType );
+        Assert.assertEquals( expected, result.getPath().replace( '\\', '/' ) );
+    }
+
+}