Add Charsets.toCharset(Charset, Charset).

Add Charsets.toCharset(String, Charset).

Author: Gary Gregory

src/changes/changes.xml

@@ -393,6 +393,10 @@ The <action> type attribute can be add,update,fix,remove.
         Add IOUtils.closeQuietly(Iterable&lt;Closeable&gt;).
         Add IOUtils.closeQuietly(Stream&lt;Closeable&gt;).
       </action>
+      <action dev="ggregory" type="add" due-to="Gary Gregory">
+        Add Charsets.toCharset(Charset, Charset).
+        Add Charsets.toCharset(String, Charset).
+      </action>
       <!-- UPDATE -->
       <action dev="kinow" type="update" due-to="Dependabot, Gary Gregory">
         Bump actions/cache from 2.1.6 to 3.0.4 #307, #337.

src/main/java/org/apache/commons/io/Charsets.java

@@ -183,6 +183,18 @@ public static Charset toCharset(final Charset charset) {
         return charset == null ? Charset.defaultCharset() : charset;
     }
 
+    /**
+     * Returns the given charset if non-null, otherwise return defaultCharset.
+     *
+     * @param charset The charset to test, may be null.
+     * @param defaultCharset The charset to return if charset is null, may be null.
+     * @return a Charset .
+     * @since 2.12.0
+     */
+    public static Charset toCharset(final Charset charset, final Charset defaultCharset) {
+        return charset == null ? defaultCharset : charset;
+    }
+
     /**
      * Returns a Charset for the named charset. If the name is null, return the default Charset.
      *
@@ -191,6 +203,19 @@ public static Charset toCharset(final Charset charset) {
      * @throws UnsupportedCharsetException If the named charset is unavailable (unchecked exception).
      */
     public static Charset toCharset(final String charsetName) throws UnsupportedCharsetException {
-        return charsetName == null ? Charset.defaultCharset() : Charset.forName(charsetName);
+        return toCharset(charsetName, Charset.defaultCharset());
+    }
+
+    /**
+     * Returns a Charset for the named charset. If the name is null, return the given default Charset.
+     *
+     * @param charsetName The name of the requested charset, may be null.
+     * @param defaultCharset The name charset to return if charsetName is null, may be null.
+     * @return a Charset for the named charset.
+     * @throws UnsupportedCharsetException If the named charset is unavailable (unchecked exception).
+     * @since 2.12.0
+     */
+    public static Charset toCharset(final String charsetName, final Charset defaultCharset) throws UnsupportedCharsetException {
+        return charsetName == null ? defaultCharset : Charset.forName(charsetName);
     }
 }

src/test/java/org/apache/commons/io/CharsetsTest.java

@@ -27,7 +27,6 @@
 
 /**
  * Tests {@link Charsets}.
- *
  */
 @SuppressWarnings("deprecation") // testing deprecated code
 public class CharsetsTest {
@@ -51,13 +50,24 @@ public void testRequiredCharsets() {
     }
 
     @Test
-    public void testToCharset() {
+    public void testToCharset_String() {
         assertEquals(Charset.defaultCharset(), Charsets.toCharset((String) null));
         assertEquals(Charset.defaultCharset(), Charsets.toCharset((Charset) null));
         assertEquals(Charset.defaultCharset(), Charsets.toCharset(Charset.defaultCharset()));
         assertEquals(StandardCharsets.UTF_8, Charsets.toCharset(StandardCharsets.UTF_8));
     }
 
+    @Test
+    public void testToCharset_String_Charset() {
+        assertEquals(null, Charsets.toCharset((String) null, null));
+        assertEquals(Charset.defaultCharset(), Charsets.toCharset((String) null, Charset.defaultCharset()));
+        assertEquals(Charset.defaultCharset(), Charsets.toCharset((Charset) null, Charset.defaultCharset()));
+        assertEquals(null, Charsets.toCharset((Charset) null, null));
+        assertEquals(Charset.defaultCharset(), Charsets.toCharset(Charset.defaultCharset(), Charset.defaultCharset()));
+        assertEquals(StandardCharsets.UTF_8, Charsets.toCharset(StandardCharsets.UTF_8, Charset.defaultCharset()));
+        assertEquals(StandardCharsets.UTF_8, Charsets.toCharset(StandardCharsets.UTF_8, null));
+    }
+
     @Test
     public void testUsAscii() {
         assertEquals("US-ASCII", Charsets.US_ASCII.name());