GEODE-7409: get latest PDX configuration of cluster in REST API for M…

…anagement (apache#4329)

* throw ENTITY_NOT_FOUND exception when no pdx configuration is found

geode-core/src/main/java/org/apache/geode/management/internal/configuration/mutators/PdxManager.java

@@ -42,7 +42,11 @@ public void delete(Pdx config, CacheConfig existing) {
 
   @Override
   public List<Pdx> list(Pdx filterConfig, CacheConfig existing) {
-    return Collections.singletonList(pdxConverter.fromXmlObject(existing.getPdx()));
+    Pdx configuration = pdxConverter.fromXmlObject(existing.getPdx());
+    if (configuration == null) {
+      return Collections.emptyList();
+    }
+    return Collections.singletonList(configuration);
   }
 
   @Override

geode-core/src/test/java/org/apache/geode/management/internal/configuration/mutators/PdxManagerTest.java

@@ -0,0 +1,40 @@
+/*
+ * 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.geode.management.internal.configuration.mutators;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import org.apache.geode.cache.configuration.CacheConfig;
+
+public class PdxManagerTest {
+  private PdxManager manager;
+  private CacheConfig config;
+
+  @Before
+  public void before() throws Exception {
+    manager = new PdxManager();
+    config = mock(CacheConfig.class);
+  }
+
+  @Test
+  public void emptyListWhenPdxNotExist() throws Exception {
+    assertThat(manager.list(null, config)).isEmpty();
+  }
+}

geode-web-management/src/distributedTest/java/org/apache/geode/management/client/ConfigurePDXDUnitTest.java

@@ -93,6 +93,10 @@ InternalLocator getLocator() {
 
   @Test
   public void configureWithNoServer() throws Exception {
+    // verify the get
+    assertThatThrownBy(() -> client.get(new Pdx())).isInstanceOf(ClusterManagementException.class)
+        .hasMessageContaining("ENTITY_NOT_FOUND");
+
     pdxType.setReadSerialized(true);
     ClusterManagementRealizationResult result = client.create(pdxType);
     assertThat(result.isSuccessful()).isTrue();
@@ -114,6 +118,8 @@ public void configureWithNoServer() throws Exception {
 
   @Test
   public void configureWithARunningServer() {
+    assertThatThrownBy(() -> client.get(new Pdx())).isInstanceOf(ClusterManagementException.class)
+        .hasMessageContaining("ENTITY_NOT_FOUND");
     MemberVM server = cluster.startServerVM(1, webContext.getLocator().getPort());
     pdxType.setReadSerialized(true);
     ClusterManagementRealizationResult result = client.create(pdxType);