[OLINGO-1191] Code Improvements

fit/src/test/java/org/apache/olingo/fit/tecsvc/client/EntityReferencesITCase.java

@@ -175,9 +175,8 @@ public class EntityReferencesITCase extends AbstractParamTecSvcITCase {
       getClient().getRetrieveRequestFactory()
             .getEntityRequest(uri)
             .execute();
-      fail();
     } catch (ODataClientErrorException e) {
-      assertEquals(HttpStatusCode.NOT_FOUND.getStatusCode(), e.getStatusLine().getStatusCode());
+      assertEquals(HttpStatusCode.NO_CONTENT.getStatusCode(), e.getStatusLine().getStatusCode());
     }
   }
     

fit/src/test/java/org/apache/olingo/fit/tecsvc/http/EmptyNavigationPropertiesITCase.java

@@ -0,0 +1,136 @@
+/*
+ * 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.fit.tecsvc.http;
+
+import static org.junit.Assert.*;
+
+import java.net.HttpURLConnection;
+import java.net.URL;
+
+import org.apache.commons.io.IOUtils;
+import org.apache.olingo.client.api.ODataClient;
+import org.apache.olingo.commons.api.http.HttpMethod;
+import org.apache.olingo.commons.api.http.HttpStatusCode;
+import org.apache.olingo.fit.AbstractBaseTestITCase;
+import org.apache.olingo.fit.tecsvc.TecSvcConst;
+import org.junit.Test;
+
+public class EmptyNavigationPropertiesITCase extends AbstractBaseTestITCase {
+
+  private static final String SERVICE_URI = TecSvcConst.BASE_URI + "/";
+
+  @Test
+  public void emptyNavigationManyFollowedByToOne() throws Exception {
+    URL url = new URL(SERVICE_URI + "ESAllPrim(32767)/NavPropertyETTwoPrimMany(32767)"
+        + "/NavPropertyETAllPrimOne?$format=json");
+
+    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+    connection.setRequestMethod(HttpMethod.GET.name()); 
+    connection.connect();
+
+    assertEquals(HttpStatusCode.NOT_FOUND.getStatusCode(), connection.getResponseCode());
+  }
+  
+  @Test
+  public void emptyNavigationManyFollowedByToMany() throws Exception {
+    URL url = new URL(SERVICE_URI + "ESAllPrim(32767)/NavPropertyETTwoPrimMany(32767)"
+        + "/NavPropertyETAllPrimMany?$format=json");
+
+    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+    connection.setRequestMethod(HttpMethod.GET.name()); 
+    connection.connect();
+
+    assertEquals(HttpStatusCode.NOT_FOUND.getStatusCode(), connection.getResponseCode());
+  }
+  
+  @Test
+  public void nonemptyNavigationManyFollowedByEmptyToOne() throws Exception {
+    URL url = new URL(SERVICE_URI + "ESAllPrim(32767)/NavPropertyETTwoPrimMany(-365)"
+        + "/NavPropertyETAllPrimOne?$format=json");
+
+    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+    connection.setRequestMethod(HttpMethod.GET.name()); 
+    connection.connect();
+
+    assertEquals(HttpStatusCode.NO_CONTENT.getStatusCode(), connection.getResponseCode());
+  }
+  
+  @Test
+  public void emptyNavigationOneFollowedByToMany() throws Exception {
+    URL url = new URL(SERVICE_URI + "ESTwoPrim(32766)/NavPropertyETAllPrimOne"
+        + "/NavPropertyETTwoPrimMany?$format=json");
+
+    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+    connection.setRequestMethod(HttpMethod.GET.name()); 
+    connection.connect();
+
+    assertEquals(HttpStatusCode.NOT_FOUND.getStatusCode(), connection.getResponseCode());
+  }
+  
+  @Test
+  public void nonemptyNavigationManyFollowedByToManyNonExistingKey() throws Exception {
+    URL url = new URL(SERVICE_URI + "ESAllPrim(32767)/NavPropertyETTwoPrimMany(-365)"
+        + "/NavPropertyETAllPrimMany(123)?$format=json");
+
+    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+    connection.setRequestMethod(HttpMethod.GET.name()); 
+    connection.connect();
+
+    assertEquals(HttpStatusCode.NOT_FOUND.getStatusCode(), connection.getResponseCode());
+  }
+  
+  @Test
+  public void emptyNavigationOne() throws Exception {
+    URL url = new URL(SERVICE_URI + "ESTwoPrim(32766)/NavPropertyETAllPrimOne?$format=json");
+
+    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+    connection.setRequestMethod(HttpMethod.GET.name()); 
+    connection.connect();
+
+    assertEquals(HttpStatusCode.NO_CONTENT.getStatusCode(), connection.getResponseCode());
+  }
+  
+  @Test
+  public void nonExistingEntityToNavigationOne() throws Exception {
+    URL url = new URL(SERVICE_URI + "ESAllPrim(12345)/NavPropertyETTwoPrimOne?$format=json");
+
+    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+    connection.setRequestMethod(HttpMethod.GET.name()); 
+    connection.connect();
+
+    assertEquals(HttpStatusCode.NOT_FOUND.getStatusCode(), connection.getResponseCode());
+  }
+  
+  @Test
+  public void emptyNavigationMany() throws Exception {
+    URL url = new URL(SERVICE_URI + "ESAllPrim(-32768)/NavPropertyETTwoPrimMany?$format=json");
+
+    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+    connection.setRequestMethod(HttpMethod.GET.name()); 
+    connection.connect();
+
+    assertEquals(HttpStatusCode.OK.getStatusCode(), connection.getResponseCode());
+    assertNotNull(IOUtils.toString(connection.getInputStream()));
+  }
+  
+  @Override
+  protected ODataClient getClient() {
+    return null;
+  }
+}

lib/server-tecsvc/src/main/java/org/apache/olingo/server/tecsvc/processor/TechnicalProcessor.java

@@ -189,6 +189,8 @@ public abstract class TechnicalProcessor implements Processor {
     }
 
     int navigationCount = 0;
+	int navigationResCount = getNavigationResourceCount(resourcePaths);
+    Link previous = null;
     while (++navigationCount < readAtMostNavigations
         && resourcePaths.get(navigationCount) instanceof UriResourceNavigation) {
       final UriResourceNavigation uriNavigationResource = (UriResourceNavigation) resourcePaths.get(navigationCount);
@@ -205,13 +207,28 @@ public abstract class TechnicalProcessor implements Processor {
       EdmEntityType edmEntityType = getEntityTypeBasedOnNavPropertyTypeCast(uriNavigationResource);
       entity = edmEntityType != null ? dataProvider.readDataFromEntity(edmEntityType, key) : entity;
       if (entity == null) {
-        throw new ODataApplicationException("Nothing found.", HttpStatusCode.NOT_FOUND.getStatusCode(), Locale.ROOT);
+        if (key.isEmpty() && (previous != null || navigationResCount == 1)) {
+          throw new ODataApplicationException("No Content", HttpStatusCode.NO_CONTENT.getStatusCode(), Locale.ROOT);
+        } else {
+          throw new ODataApplicationException("Not Found", HttpStatusCode.NOT_FOUND.getStatusCode(), Locale.ROOT);
+        }
       }
+	  previous = link;
     }
 
     return entity;
   }
   
+  private int getNavigationResourceCount(List<UriResource> resourcePaths) {
+    int count = 0;
+    for (UriResource resource : resourcePaths) {
+      if (resource instanceof UriResourceNavigation) {
+        count ++;
+      }
+    }
+    return count;
+  }
+  
   private EdmEntityType getEntityTypeBasedOnNavPropertyTypeCast(UriResourceNavigation uriNavigationResource) {
     if (uriNavigationResource.getTypeFilterOnCollection() != null) {
       return (EdmEntityType) uriNavigationResource.getTypeFilterOnCollection();