nouveau welcome message for version negotiation

Author: rnewson

nouveau/src/main/java/org/apache/couchdb/nouveau/NouveauApplication.java

@@ -28,6 +28,7 @@
 import org.apache.couchdb.nouveau.lucene.ParallelSearcherFactory;
 import org.apache.couchdb.nouveau.resources.AnalyzeResource;
 import org.apache.couchdb.nouveau.resources.IndexResource;
+import org.apache.couchdb.nouveau.resources.WelcomeResource;
 import org.apache.couchdb.nouveau.tasks.CloseAllIndexesTask;
 
 public class NouveauApplication extends Application<NouveauApplicationConfiguration> {
@@ -67,6 +68,10 @@ public void run(NouveauApplicationConfiguration configuration, Environment envir
         // Serialization classes
         environment.getObjectMapper().registerModule(new LuceneModule());
 
+        // WelcomeResource
+        final WelcomeResource welcomeResource = new WelcomeResource();
+        environment.jersey().register(welcomeResource);
+
         // AnalyzeResource
         final AnalyzeResource analyzeResource = new AnalyzeResource();
         environment.jersey().register(analyzeResource);

nouveau/src/main/java/org/apache/couchdb/nouveau/api/WelcomeResponse.java

@@ -0,0 +1,34 @@
+//
+// 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.apache.couchdb.nouveau.api;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.databind.PropertyNamingStrategies;
+import com.fasterxml.jackson.databind.annotation.JsonNaming;
+
+@JsonNaming(PropertyNamingStrategies.SnakeCaseStrategy.class)
+public final class WelcomeResponse {
+
+    public static final WelcomeResponse INSTANCE = new WelcomeResponse();
+
+    private final int[] supportedLuceneVersions =
+            new int[] {IndexDefinition.LEGACY_LUCENE_VERSION, IndexDefinition.LATEST_LUCENE_VERSION};
+
+    private WelcomeResponse() {}
+
+    @JsonProperty
+    public int[] getSupportedLuceneVersions() {
+        return supportedLuceneVersions;
+    }
+}

nouveau/src/main/java/org/apache/couchdb/nouveau/core/IndexManager.java

@@ -219,7 +219,6 @@ public void create(final String name, IndexDefinition indexDefinition) throws IO
             assertSame(indexDefinition, loadIndexDefinition(name));
             return;
         }
-
         final Lock lock = this.createLock.writeLock(name);
         lock.lock();
         try {

nouveau/src/main/java/org/apache/couchdb/nouveau/resources/WelcomeResource.java

@@ -0,0 +1,30 @@
+//
+// 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.apache.couchdb.nouveau.resources;
+
+import jakarta.ws.rs.GET;
+import jakarta.ws.rs.Path;
+import jakarta.ws.rs.Produces;
+import jakarta.ws.rs.core.MediaType;
+import org.apache.couchdb.nouveau.api.WelcomeResponse;
+
+@Path("/")
+@Produces(MediaType.APPLICATION_JSON)
+public final class WelcomeResource {
+
+    @GET
+    public WelcomeResponse welcome() {
+        return WelcomeResponse.INSTANCE;
+    }
+}