[GitHub] [lucene-solr] mikemccand commented on a change in pull request #1319: LUCENE-9164: process all events before closing gracefully

[GitBox <gi...@apache.org>]

mikemccand commented on a change in pull request #1319: LUCENE-9164: process all events before closing gracefully
URL: https://github.com/apache/lucene-solr/pull/1319#discussion_r389387448
 
 

 ##########
 File path: lucene/core/src/java/org/apache/lucene/index/IndexWriter.java
 ##########
 @@ -299,7 +300,77 @@ static int getActualMaxDocs() {
   final FieldNumbers globalFieldNumberMap;
 
   final DocumentsWriter docWriter;
-  private final Queue<Event> eventQueue = new ConcurrentLinkedQueue<>();
+  private final EventQueue eventQueue = new EventQueue(this);
+
+  static final class EventQueue implements Closeable {
+    private volatile boolean closed = false;
+    private final Semaphore permits = new Semaphore(Integer.MAX_VALUE);
+    private final Queue<Event> queue = new ConcurrentLinkedQueue<>();
+    private final IndexWriter writer;
+
+    EventQueue(IndexWriter writer) {
+      this.writer = writer;
+    }
+
+    private void tryAcquire() {
+      if (permits.tryAcquire() == false) {
+        throw new AlreadyClosedException("queue is closed");
+      }
+      if (closed) {
+        throw new AlreadyClosedException("queue is closed");
+      }
+    }
+
+    boolean add(Event event) {
+      tryAcquire();
+      try {
+        return queue.add(event);
+      } finally {
+        permits.release();
+      }
+    }
+
+    void processEvents() throws IOException {
+      tryAcquire();
+      try {
+        processEventsInternal();
+      } finally {
+        permits.release();
+      }
+    }
+
+    private void processEventsInternal() throws IOException {
+      assert Integer.MAX_VALUE - permits.availablePermits() > 0 : "must acquire a permit before processing events";
 
 Review comment:
   Maybe rewrite to `assert permits.availablePermits() < Integer.MAX_VALUE` for easier readability?

----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
users@infra.apache.org


With regards,
Apache Git Services

---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@lucene.apache.org
For additional commands, e-mail: issues-help@lucene.apache.org