Make TextPlainEngine return some String-based values

CHANGELOG.md

@@ -22,6 +22,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 - Upgrade [pippo-jade] to Jade 1.1.4
 - Upgrade [pippo-pebble] to Pebble 2.2.1
 - Make `chunked` transfer-encoding optional, not the default
+- Make the text/plain content type engine handle returning reasonable types like String, CharSequence, char[], and byte[]
 
 #### Added
 - [#245]: Route groups

pippo-core/src/main/java/ro/pippo/core/TextPlainEngine.java

@@ -16,6 +16,8 @@
 package ro.pippo.core;
 
 
+import java.nio.charset.StandardCharsets;
+
 /**
  * A text/plain engine based on toString()
  *
@@ -39,6 +41,16 @@ public String toString(Object object) {
 
     @Override
     public <T> T fromString(String content, Class<T> classOfT) {
+        if (String.class.equals(classOfT)) {
+            return (T) content;
+        } else if (CharSequence.class.equals(classOfT)) {
+            return (T) content;
+        } else if (char[].class.equals(classOfT)) {
+            return (T) content.toCharArray();
+        } else if (byte[].class.equals(classOfT)) {
+            return (T) content.getBytes(StandardCharsets.UTF_8);
+        }
+
         throw new PippoRuntimeException("Sorry, can not transform '{}' content to '{}'", getContentType(),
             classOfT.getName());
     }