CLI-277: Add generics to TypeHandler

Author: britter

src/main/java/org/apache/commons/cli/TypeHandler.java

@@ -61,43 +61,44 @@ public static Object createValue(final String str, final Object obj) throws Pars
      * the value of <code>str</code>.
      * @throws ParseException if the value creation for the given class failed
      */
-    public static Object createValue(final String str, final Class<?> clazz) throws ParseException
+    @SuppressWarnings("unchecked") // returned value will have type T because it is fixed by clazz
+    public static <T> T createValue(final String str, final Class<T> clazz) throws ParseException
     {
         if (PatternOptionBuilder.STRING_VALUE == clazz)
         {
-            return str;
+            return (T) str;
         }
         else if (PatternOptionBuilder.OBJECT_VALUE == clazz)
         {
-            return createObject(str);
+            return (T) createObject(str);
         }
         else if (PatternOptionBuilder.NUMBER_VALUE == clazz)
         {
-            return createNumber(str);
+            return (T) createNumber(str);
         }
         else if (PatternOptionBuilder.DATE_VALUE == clazz)
         {
-            return createDate(str);
+            return (T) createDate(str);
         }
         else if (PatternOptionBuilder.CLASS_VALUE == clazz)
         {
-            return createClass(str);
+            return (T) createClass(str);
         }
         else if (PatternOptionBuilder.FILE_VALUE == clazz)
         {
-            return createFile(str);
+            return (T) createFile(str);
         }
         else if (PatternOptionBuilder.EXISTING_FILE_VALUE == clazz)
         {
-            return openFile(str);
+            return (T) openFile(str);
         }
         else if (PatternOptionBuilder.FILES_VALUE == clazz)
         {
-            return createFiles(str);
+            return (T) createFiles(str);
         }
         else if (PatternOptionBuilder.URL_VALUE == clazz)
         {
-            return createURL(str);
+            return (T) createURL(str);
         }
         else
         {

src/test/java/org/apache/commons/cli/TypeHandlerTest.java

@@ -0,0 +1,159 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.cli;
+
+import org.junit.Test;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.net.URL;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+public class TypeHandlerTest
+{
+
+    @Test
+    public void testCreateValueString()
+        throws Exception
+    {
+        assertEquals("String", TypeHandler.createValue("String", PatternOptionBuilder.STRING_VALUE));
+    }
+
+    @Test(expected = ParseException.class)
+    public void testCreateValueObject_unknownClass()
+        throws Exception
+    {
+        TypeHandler.createValue("unknown", PatternOptionBuilder.OBJECT_VALUE);
+    }
+
+    @Test(expected = ParseException.class)
+    public void testCreateValueObject_notInstantiableClass()
+        throws Exception
+    {
+        TypeHandler.createValue(NotInstantiable.class.getName(), PatternOptionBuilder.OBJECT_VALUE);
+    }
+
+    @Test
+    public void testCreateValueObject_InstantiableClass()
+        throws Exception
+    {
+        Object result = TypeHandler.createValue(Instantiable.class.getName(), PatternOptionBuilder.OBJECT_VALUE);
+        assertTrue(result instanceof Instantiable);
+    }
+
+    @Test(expected = ParseException.class)
+    public void testCreateValueNumber_noNumber()
+        throws Exception
+    {
+        TypeHandler.createValue("not a number", PatternOptionBuilder.NUMBER_VALUE);
+    }
+
+    @Test
+    public void testCreateValueNumber_Double()
+        throws Exception
+    {
+        assertEquals(1.5d, TypeHandler.createValue("1.5", PatternOptionBuilder.NUMBER_VALUE));
+    }
+
+    @Test
+    public void testCreateValueNumber_Long()
+        throws Exception
+    {
+        assertEquals(Long.valueOf(15), TypeHandler.createValue("15", PatternOptionBuilder.NUMBER_VALUE));
+    }
+
+    @Test(expected = UnsupportedOperationException.class)
+    public void testCreateValueDate()
+        throws Exception
+    {
+        TypeHandler.createValue("what ever", PatternOptionBuilder.DATE_VALUE);
+    }
+
+    @Test(expected = ParseException.class)
+    public void testCreateValueClass_notFound()
+        throws Exception
+    {
+        TypeHandler.createValue("what ever", PatternOptionBuilder.CLASS_VALUE);
+    }
+
+    @Test
+    public void testCreateValueClass()
+        throws Exception
+    {
+        Object clazz = TypeHandler.createValue(Instantiable.class.getName(), PatternOptionBuilder.CLASS_VALUE);
+        assertEquals(Instantiable.class, clazz);
+    }
+
+    @Test
+    public void testCreateValueFile()
+            throws Exception
+    {
+        File result = TypeHandler.createValue("some-file.txt", PatternOptionBuilder.FILE_VALUE);
+        assertEquals("some-file.txt", result.getName());
+    }
+
+    @Test
+    public void testCreateValueExistingFile()
+            throws Exception
+    {
+        FileInputStream result = TypeHandler.createValue("src/test/resources/existing-readable.file", PatternOptionBuilder.EXISTING_FILE_VALUE);
+        assertNotNull(result);
+    }
+
+    @Test(expected = ParseException.class)
+    public void testCreateValueExistingFile_nonExistingFile()
+            throws Exception
+    {
+        TypeHandler.createValue("non-existing.file", PatternOptionBuilder.EXISTING_FILE_VALUE);
+    }
+
+    @Test(expected = UnsupportedOperationException.class)
+    public void testCreateValueFiles()
+            throws Exception
+    {
+        TypeHandler.createValue("some.files", PatternOptionBuilder.FILES_VALUE);
+    }
+
+    @Test
+    public void testCreateValueURL()
+            throws Exception
+    {
+        String urlString = "http://commons.apache.org";
+        URL result = TypeHandler.createValue(urlString, PatternOptionBuilder.URL_VALUE);
+        assertEquals(urlString, result.toString());
+    }
+
+    @Test(expected = ParseException.class)
+    public void testCreateValueURL_malformed()
+            throws Exception
+    {
+        TypeHandler.createValue("malformed-url", PatternOptionBuilder.URL_VALUE);
+    }
+
+    public static class Instantiable
+    {
+    }
+
+    public static class NotInstantiable
+    {
+        private NotInstantiable() {}
+    }
+}