Initial sketch of codecs and REST API approach.
FIxed typos and defects.
ONOS-81
Change-Id: I789444a181abea509c354966545c927e305710d1
diff --git a/web/api/src/main/java/org/onlab/onos/rest/AbstractWebResource.java b/web/api/src/main/java/org/onlab/onos/rest/AbstractWebResource.java
new file mode 100644
index 0000000..ee9adb0
--- /dev/null
+++ b/web/api/src/main/java/org/onlab/onos/rest/AbstractWebResource.java
@@ -0,0 +1,81 @@
+/*
+ * Copyright 2014 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.onlab.onos.rest;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.onlab.api.ItemNotFoundException;
+import org.onlab.onos.codec.CodecContext;
+import org.onlab.onos.codec.CodecService;
+import org.onlab.onos.codec.JsonCodec;
+import org.onlab.rest.BaseResource;
+
+/**
+ * Abstract REST resource.
+ */
+public class AbstractWebResource extends BaseResource implements CodecContext {
+
+ @Override
+ public ObjectMapper mapper() {
+ return new ObjectMapper();
+ }
+
+ /**
+ * Returns the JSON codec for the specified entity class.
+ *
+ * @param entityClass entity class
+ * @param <T> entity type
+ * @return JSON codec
+ */
+ public <T> JsonCodec<T> codec(Class<T> entityClass) {
+ return get(CodecService.class).getCodec(entityClass);
+ }
+
+ /**
+ * Returns JSON object wrapping the array encoding of the specified
+ * collection of items.
+ *
+ * @param codecClass codec item class
+ * @param field field holding the array
+ * @param items collection of items to be encoded into array
+ * @param <T> item type
+ * @return JSON object
+ */
+ protected <T> ObjectNode encodeArray(Class<T> codecClass, String field,
+ Iterable<T> items) {
+ ObjectNode result = mapper().createObjectNode();
+ result.set(field, codec(codecClass).encode(items, this));
+ return result;
+ }
+
+ /**
+ * Returns the specified item if that items is null; otherwise throws
+ * not found exception.
+ *
+ * @param item item to check
+ * @param message not found message
+ * @param <T> item type
+ * @return item if not null
+ * @throws org.onlab.api.ItemNotFoundException if item is null
+ */
+ protected <T> T nullIsNotFound(T item, String message) {
+ if (item == null) {
+ throw new ItemNotFoundException(message);
+ }
+ return item;
+ }
+
+}