[OLINGO-211] Preliminary Servlet

Only a prototype to give back metadata and service document

lib/server-core/pom.xml

@@ -44,6 +44,11 @@
       <groupId>org.apache.olingo</groupId>
       <artifactId>olingo-commons-core</artifactId>
       <version>${project.version}</version>
+    </dependency>
+        <dependency>
+      <groupId>javax.servlet</groupId>
+      <artifactId>javax.servlet-api</artifactId>
+      <version>${servlet.version}</version>
     </dependency>
     <dependency>
       <groupId>junit</groupId>

lib/server-core/src/main/java/org/apache/olingo/server/core/servlet/ODataServlet.java

@@ -0,0 +1,86 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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.apache.olingo.server.core.servlet;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import javax.servlet.ServletOutputStream;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.apache.olingo.server.api.edm.provider.EdmProvider;
+import org.apache.olingo.server.api.serializer.ODataFormat;
+import org.apache.olingo.server.api.serializer.ODataSerializer;
+import org.apache.olingo.server.core.ODataServerImpl;
+import org.apache.olingo.server.core.edm.provider.EdmProviderImpl;
+
+public class ODataServlet extends HttpServlet {
+
+  private static final long serialVersionUID = 1L;
+
+  private HttpServletResponse resp;
+
+  @Override
+  protected void service(final HttpServletRequest req, final HttpServletResponse resp) throws IOException {
+    this.resp = resp;
+
+    EdmProvider provider = createEdmProvider();
+    EdmProviderImpl edm = new EdmProviderImpl(provider);
+
+    ODataServerImpl impl = new ODataServerImpl();
+    InputStream responseEntity = null;
+    if (req.getPathInfo().contains("$metadata")) {
+      ODataSerializer serializer = impl.getSerializer(ODataFormat.XML);
+      responseEntity = serializer.metadataDocument(edm);
+    } else {
+      ODataSerializer serializer = impl.getSerializer(ODataFormat.JSON);
+      responseEntity = serializer.serviceDocument(edm, "http//:root");
+    }
+    sendResponse(responseEntity);
+  }
+
+  protected EdmProvider createEdmProvider() {
+    return null;
+  }
+
+  // TODO: check throws
+  private void sendResponse(Object entity) throws IOException {
+    resp.setStatus(200);
+    resp.setContentType("application/json");
+    if (entity != null) {
+      ServletOutputStream out = resp.getOutputStream();
+      int curByte = -1;
+      if (entity instanceof InputStream) {
+        while ((curByte = ((InputStream) entity).read()) != -1) {
+          out.write((char) curByte);
+        }
+        ((InputStream) entity).close();
+      } else if (entity instanceof String) {
+        String body = (String) entity;
+        out.write(body.getBytes("utf-8"));
+      }
+
+      out.flush();
+      out.close();
+    }
+  }
+
+}