added *Generator.addPage(Supplier<String>)

Author: jirka.pinkas@gmail.com

src/main/java/cz/jiripinkas/jsitemapgenerator/AbstractGenerator.java

@@ -73,6 +73,23 @@ public I addPage(String name) {
         return addPage(WebPage.of(name));
     }
 
+    /**
+     * Add single page to sitemap.
+     * @param supplier Supplier method which sneaks any checked exception
+     *                 https://www.baeldung.com/java-sneaky-throws
+     *                 Allows for calling method which performs some operation and then returns name of page.
+     * @return this
+     */
+    public I addPage(StringSupplierWithException<String> supplier) {
+        try {
+            addPage(supplier.get());
+        } catch (Exception e) {
+            sneakyThrow(e);
+        }
+        return getThis();
+    }
+
+
     /**
      * This method is called before adding a page to urls.
      * It can be used to change webPage attributes
@@ -223,6 +240,10 @@ public interface GeneratorConsumerWithException<T> {
         void accept(T t) throws Exception;
     }
 
+    public interface StringSupplierWithException<String> {
+        String get() throws Exception;
+    }
+
     /**
      * Sneak exception https://www.baeldung.com/java-sneaky-throws
      * @param e Exception