JCL-417: Add ldp validation handling to example code (#589)

Author: acoburn

examples/webapp/src/main/java/com/inrupt/client/examples/webapp/ClientExceptionMapper.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright Inrupt Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+ * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+ * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.inrupt.client.examples.webapp;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.slf4j.LoggerFactory.getLogger;
+
+import com.inrupt.client.solid.DataMappingException;
+
+import io.quarkus.qute.CheckedTemplate;
+import io.quarkus.qute.TemplateInstance;
+
+import jakarta.ws.rs.core.MediaType;
+import jakarta.ws.rs.core.Response;
+import jakarta.ws.rs.ext.ExceptionMapper;
+import jakarta.ws.rs.ext.Provider;
+
+import java.io.ByteArrayInputStream;
+import java.util.Collection;
+
+import org.slf4j.Logger;
+
+@Provider
+public class ClientExceptionMapper implements ExceptionMapper<DataMappingException> {
+
+    private static final Logger LOGGER = getLogger(ClientExceptionMapper.class);
+
+    @CheckedTemplate
+    static class Templates {
+        private static native TemplateInstance error(
+                String message,
+                Collection<String> errors);
+    }
+
+    @Override
+    public Response toResponse(final DataMappingException err) {
+        LOGGER.debug("Web Application Error: {}", err.getMessage());
+
+        final var errorHtml = Templates.error("Invalid container", err.getValidationResults()).render();
+
+        final var response = new ByteArrayInputStream(errorHtml.getBytes(UTF_8));
+
+        return Response.status(400)
+                       .entity(response)
+                       .type(MediaType.TEXT_HTML)
+                       .build();
+    }
+}

examples/webapp/src/main/resources/templates/ClientExceptionMapper/error.html

@@ -0,0 +1,12 @@
+{#include master}
+  {#body}
+  <h3>Error</h3>
+  <p><strong>{message}</strong></p>
+  <ul>
+    {#for item in errors}
+      <li>{item}</li>
+    {/for}
+  </ul>
+  {/body}
+{/include}
+