Added RenderUtils and more tests.

lib/src/main/java/rife/render/RenderUtils.java

@@ -0,0 +1,48 @@
+/*
+ *  Copyright 2023 the original author or authors.
+ *
+ *  Licensed 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
+ *
+ *       https://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 rife.render;
+
+import rife.template.Template;
+import rife.tools.Convert;
+
+/**
+ * Collection of utility-type methods commonly used by the renderers.
+ */
+public final  class RenderUtils {
+    private RenderUtils() {
+        // no-op
+    }
+
+    /**
+     * Fetches the specified value from a template or template's attribute.
+     *
+     * @param template the template
+     * @param valueId  the ID of the value to fetch
+     * @return The fetched value.
+     */
+    public static String fetchValue(Template template, String valueId) {
+        Object value = null;
+        if (template.hasValueId(valueId)) {
+            value = template.getValue(valueId);
+        }
+        if (value == null && template.hasAttribute(valueId)) {
+            value = template.getAttribute(valueId);
+        }
+        return Convert.toString(value);
+    }
+}