Initial commit

lib/src/main/java/rife2/render/SwapCase.java

@@ -0,0 +1,80 @@
+/*
+ *  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 rife2.render;
+
+import rife.template.Template;
+import rife.template.ValueRenderer;
+
+/**
+ * <p>Swap case of a template value.</p>
+ *
+ * <p>Usage:</p>
+ *
+ * <pre>
+ *   &lt;!--v render:rife.render.SwapCase:valueId/--&gt;
+ *   {{v render:rife.render.SwapCase:valueId}}
+ * </pre>
+ *
+ * @author <a href="https://erik.thauvin.net/">Erik C. Thauvin</a>
+ * @since 1.0
+ */
+public class SwapCase implements ValueRenderer {
+    /**
+     * Swaps the case of a String.
+     * @param s the String to swap the case of
+     * @return the modified String or null
+     */
+    public static String swapCase(String s) {
+        if (s == null || s.isEmpty()) {
+            return s;
+        }
+
+        var buffer = s.toCharArray();
+        var whitespace = true;
+
+        for (var i = 0; i < buffer.length; i++) {
+            var ch = buffer[i];
+            if (Character.isUpperCase(ch) || Character.isTitleCase(ch)) {
+                buffer[i] = Character.toLowerCase(ch);
+                whitespace = false;
+            } else if (Character.isLowerCase(ch)) {
+                if (whitespace) {
+                    buffer[i] = Character.toTitleCase(ch);
+                    whitespace = false;
+                } else {
+                    buffer[i] = Character.toUpperCase(ch);
+                }
+            } else {
+                whitespace = Character.isWhitespace(ch);
+            }
+        }
+        return new String(buffer);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public String render(Template template, String valueId, String differentiator) {
+        if (differentiator != null && !differentiator.isBlank() && template.hasValueId(differentiator)) {
+            return swapCase(template.getValue(differentiator));
+        } else {
+            return "";
+        }
+    }
+}