GH-83: fix: Merge operations when repeated ChannelItem found (#88)

As mentioned in GH-83, only one channelItem is part of the final map - although both channelItems are found.

This improves the situation by merging the different operations for the same topic name into the same ChannelItem - while still the last one wins.

Author: timonback

springwolf-core/src/main/java/io/github/stavshamir/springwolf/asyncapi/DefaultChannelsService.java

@@ -1,6 +1,7 @@
 package io.github.stavshamir.springwolf.asyncapi;
 
 import com.asyncapi.v2.model.channel.ChannelItem;
+import com.asyncapi.v2.model.channel.operation.Operation;
 import io.github.stavshamir.springwolf.asyncapi.scanners.channels.ChannelsScanner;
 import java.util.HashMap;
 import lombok.RequiredArgsConstructor;
@@ -28,13 +29,34 @@ void findChannels() {
 
         for (ChannelsScanner scanner : channelsScanners) {
             try {
-                channels.putAll(scanner.scan());
+                Map<String, ChannelItem> channels = scanner.scan();
+                processFoundChannels(channels);
             } catch (Exception e) {
                 log.error("An error was encountered during channel scanning with {}: {}", scanner, e.getMessage());
             }
         }
     }
 
+    private void processFoundChannels(Map<String, ChannelItem> foundChannels) {
+        for (Map.Entry<String, ChannelItem> foundChannel: foundChannels.entrySet()) {
+            if (!this.channels.containsKey(foundChannel.getKey())) {
+                this.channels.put(foundChannel.getKey(), foundChannel.getValue());
+            } else {
+                ChannelItem existingChannel = this.channels.get(foundChannel.getKey());
+
+                Operation subscribeOperation = foundChannel.getValue().getSubscribe();
+                if(subscribeOperation != null) {
+                    existingChannel.setSubscribe(subscribeOperation);
+                }
+
+                Operation publishOperation = foundChannel.getValue().getPublish();
+                if(publishOperation != null) {
+                    existingChannel.setPublish(publishOperation);
+                }
+            }
+        }
+    }
+
     @Override
     public Map<String, ChannelItem> getChannels() {
         return channels;

springwolf-core/src/test/java/io/github/stavshamir/springwolf/asyncapi/DefaultChannelsServiceTest.java

@@ -1,6 +1,7 @@
 package io.github.stavshamir.springwolf.asyncapi;
 
 import com.asyncapi.v2.model.channel.ChannelItem;
+import com.asyncapi.v2.model.channel.operation.Operation;
 import com.google.common.collect.ImmutableMap;
 import io.github.stavshamir.springwolf.asyncapi.scanners.channels.ChannelsScanner;
 import org.junit.Test;
@@ -18,7 +19,9 @@
 @ContextConfiguration(classes = {
         DefaultChannelsService.class,
         DefaultChannelsServiceTest.FooChannelScanner.class,
-        DefaultChannelsServiceTest.BarChannelScanner.class
+        DefaultChannelsServiceTest.BarChannelScanner.class,
+        DefaultChannelsServiceTest.SameTopic.SubscribeChannelScanner.class,
+        DefaultChannelsServiceTest.SameTopic.ProduceChannelScanner.class
 })
 public class DefaultChannelsServiceTest {
 
@@ -37,7 +40,8 @@ public void getChannels() {
 
         assertThat(actualChannels)
                 .containsAllEntriesOf(fooChannelScanner.scan())
-                .containsAllEntriesOf(barChannelScanner.scan());
+                .containsAllEntriesOf(barChannelScanner.scan())
+                .containsEntry(SameTopic.topicName, SameTopic.expectedMergedChannel);
     }
 
     @Component
@@ -56,4 +60,32 @@ public Map<String, ChannelItem> scan() {
         }
     }
 
+    static class SameTopic {
+        static final String topicName = "subscribeProduceTopic";
+        static final ChannelItem expectedMergedChannel = ChannelItem.builder()
+            .publish(SameTopic.ProduceChannelScanner.publishOperation)
+            .subscribe(SameTopic.SubscribeChannelScanner.subscribeOperation)
+            .build();
+
+        @Component
+        static class ProduceChannelScanner implements ChannelsScanner {
+            static final Operation publishOperation = Operation.builder().message("publish").build();
+
+            @Override
+            public Map<String, ChannelItem> scan() {
+                return ImmutableMap.of(topicName, ChannelItem.builder().publish(publishOperation).build());
+            }
+        }
+
+        @Component
+        static class SubscribeChannelScanner implements ChannelsScanner {
+            static final Operation subscribeOperation = Operation.builder().message("consumer").build();
+
+            @Override
+            public Map<String, ChannelItem> scan() {
+                return ImmutableMap.of(topicName, ChannelItem.builder().subscribe(subscribeOperation).build());
+            }
+        }
+    }
+
 }