1 files changed, 77 insertions, 0 deletions
diff --git a/framework/src/onos/web/api/src/main/java/org/onosproject/rest/exceptions/AbstractMapper.java b/framework/src/onos/web/api/src/main/java/org/onosproject/rest/exceptions/AbstractMapper.java
new file mode 100644
index 00000000..f49202dd
--- /dev/null
+++ b/framework/src/onos/web/api/src/main/java/org/onosproject/rest/exceptions/AbstractMapper.java
@@ -0,0 +1,77 @@
+/*
+ * Copyright 2014-2015 Open Networking Laboratory
+ *
+ * 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
+ *
+ *     http://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 org.onosproject.rest.exceptions;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+
+import javax.ws.rs.core.Response;
+import javax.ws.rs.ext.ExceptionMapper;
+
+import static com.google.common.base.Strings.isNullOrEmpty;
+
+/**
+ * Base exception mapper implementation.
+ */
+public abstract class AbstractMapper<E extends Throwable> implements ExceptionMapper<E> {
+
+    /**
+     * Returns the response status to be given when the exception occurs.
+     *
+     * @return response status
+     */
+    protected abstract Response.Status responseStatus();
+
+    @Override
+    public Response toResponse(E exception) {
+        return response(responseStatus(), exception).build();
+    }
+
+    /**
+     * Produces a response builder primed with the supplied status code
+     * and JSON entity with the status code and exception message.
+     *
+     * @param status    response status
+     * @param exception exception to encode
+     * @return response builder
+     */
+    protected Response.ResponseBuilder response(Response.Status status,
+                                                Throwable exception) {
+        ObjectMapper mapper = new ObjectMapper();
+        String message = messageFrom(exception);
+        ObjectNode result = mapper.createObjectNode()
+                .put("code", status.getStatusCode())
+                .put("message", message);
+        return Response.status(status).entity(result.toString());
+    }
+
+    /**
+     * Produces a response message from the supplied exception. Either it will
+     * use the exception message, if there is one, or it will use the top
+     * stack-frame message.
+     *
+     * @param exception exception from which to produce a message
+     * @return response message
+     */
+    protected String messageFrom(Throwable exception) {
+        if (isNullOrEmpty(exception.getMessage())) {
+            StackTraceElement[] trace = exception.getStackTrace();
+            return trace.length == 0 ? "Unknown error" : trace[0].toString();
+        }
+        return exception.getMessage();
+    }
+
+}