WIP: Dirty in-place implementation

[demos/kafka/wordcount] / src / main / java / de / juplo / kafka / wordcount / top10 / Top10StreamProcessor.java

diff --git a/src/main/java/de/juplo/kafka/wordcount/top10/Top10StreamProcessor.java b/src/main/java/de/juplo/kafka/wordcount/top10/Top10StreamProcessor.java
index 811cf98..2bc1da7 100644 (file)
--- a/src/main/java/de/juplo/kafka/wordcount/top10/Top10StreamProcessor.java
+++ b/src/main/java/de/juplo/kafka/wordcount/top10/Top10StreamProcessor.java
@@ -21,7 +21,9 @@ import org.springframework.stereotype.Component;
 
 import javax.annotation.PostConstruct;
 import javax.annotation.PreDestroy;
+import java.util.Arrays;
 import java.util.LinkedList;
+import java.util.List;
 import java.util.Properties;
 import java.util.concurrent.CompletableFuture;
 import java.util.regex.Pattern;
@@ -53,8 +55,39 @@ public class Top10StreamProcessor
                                .groupByKey(Grouped.keySerde(Serdes.String()))
                                .aggregate(
                                                () -> Ranking.newBuilder().setEntries(new LinkedList<Entry>()).build(),
-                                               (username, entry, ranking) -> {
-                                                       ranking.getEntries().add(entry);
+                                               (username, newEntry, ranking) -> {
+                                                       List<Entry> entries = new LinkedList<>(ranking.getEntries());
+
+                                                       if (entries.isEmpty())
+                                                       {
+                                                               entries.add(newEntry);
+                                                       }
+                                                       else
+                                                       {
+                                                               for (int i = 0; i < entries.size(); i++)
+                                                               {
+                                                                       Entry entry = entries.get(i);
+                                                                       if (entry.getCount() <= newEntry.getCount())
+                                                                       {
+                                                                               entries.add(i, newEntry);
+                                                                               for (int j = i + 1; j < entries.size(); j++)
+                                                                               {
+                                                                                       entry = entries.get(j);
+                                                                                       if (entry.getWord().equals(newEntry.getWord()))
+                                                                                       {
+                                                                                               entries.remove(j);
+                                                                                               break;
+                                                                                       }
+                                                                               }
+                                                                               if (entries.size() > 10)
+                                                                               {
+                                                                                       entries = entries.subList(0, 10);
+                                                                               }
+                                                                       }
+                                                               }
+                                                       }
+
+                                                       ranking.setEntries(entries);
                                                        return ranking;
                                                })
                                .toStream()