docs: add Javadoc

src/main/java/com/github/polpetta/mezzotre/i18n/TemplateContentGenerator.java

@@ -9,6 +9,14 @@ import org.apache.velocity.tools.ToolManager;
 import org.apache.velocity.util.StringBuilderWriter;
 
 // FIXME doc, tests
+
+/**
+ * This class aims to generate localized messages or strings either merging Velocity templates or
+ * taking directly the keys from {@link java.util.ResourceBundle}
+ *
+ * @author Davide Polonio
+ * @since 1.0
+ */
 public class TemplateContentGenerator {
 
   private final LocalizedMessageFactory localizedMessageFactory;
@@ -18,6 +26,19 @@ public class TemplateContentGenerator {
     this.localizedMessageFactory = localizedMessageFactory;
   }
 
+  /**
+   * Merge a Velocity template located in the local Jar resource path with the given {@link Locale},
+   * provided as a {@link String}. A {@link Consumer} is provided in order to let the user customize
+   * the {@link VelocityContext} with additional variables. Localization strings will be directly
+   * taken via the use of {@link LocalizedTool} class.
+   *
+   * @param velocityContextConsumer a lambda function that allows for the customization of {@link
+   *     VelocityContext} instance
+   * @param localeAsString a {@link Locale} formatted as a {@link String}. Note that {@link
+   *     Locale#forLanguageTag(String)} will be used for the conversion
+   * @param templateName the path to the local Jar resource
+   * @return a {@link String} containing the localized message
+   */
   public String mergeTemplate(
       Consumer<VelocityContext> velocityContextConsumer,
       String localeAsString,