fixed various serialization issues relating to silent ehcache put() a…

…nd get() failures

server/build.gradle

@@ -159,7 +159,7 @@ dependencies {
   api "jakarta.annotation:jakarta.annotation-api:${versions.jakarta_annotation}"
 
   // ehcache
-  api "org.ehcache:ehcache:3.10.8"
+  api "org.ehcache:ehcache:3.10.8" // using 3.3.1 rather than 3.10.8 to test if dependency conflicts are causing my issues
   api "org.slf4j:slf4j-api:1.7.36"
 
   testImplementation(project(":test:framework")) {

server/src/main/java/org/opensearch/indices/DummySerializableKey.java

@@ -0,0 +1,50 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices;
+
+import java.io.Serializable;
+import java.util.Objects;
+
+public class DummySerializableKey implements Serializable {
+    private Integer i;
+    private String s;
+    public DummySerializableKey(Integer i, String s) {
+        this.i = i;
+        this.s = s;
+    }
+
+    public int getI() {
+        return i;
+    }
+    public String getS() {
+        return s;
+    }
+    @Override
+    public boolean equals(Object o) {
+        if (o == this) {
+            return true;
+        }
+        if (!(o instanceof DummySerializableKey)) {
+            return false;
+        }
+        DummySerializableKey other = (DummySerializableKey) o;
+        return Objects.equals(this.i, other.i) && this.s.equals(other.s);
+    }
+    @Override
+    public final int hashCode() {
+        int result = 11;
+        if (i != null) {
+            result = 31 * result + i.hashCode();
+        }
+        if (s != null) {
+            result = 31 * result + s.hashCode();
+        }
+        return result;
+    }
+}

server/src/main/java/org/opensearch/indices/EhcacheEventListener.java

@@ -41,7 +41,7 @@ public void onEvent(CacheEvent<? extends K, ? extends V> event) {
         } else if (oldValue != null && newValue == null) {
             counter.dec();
         } else {
-            int j;
+            int j; // breakpoint
         }
 
         // handle creating a RemovalReason, unless eventType is CREATED

server/src/test/java/org/opensearch/indices/IndicesRequestCacheTests.java

@@ -78,7 +78,9 @@
 
 import java.io.IOException;
 import java.io.Serializable;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 public class IndicesRequestCacheTests extends OpenSearchTestCase {
@@ -194,17 +196,58 @@ public void onRemoval(RemovalNotification<Integer, String> notification) {
             .defaultPool("default", 0, 4)
             .build();
 
-        PersistentCacheManager cacheManager = CacheManagerBuilder.newCacheManagerBuilder()
-            .using(statsService) // https://stackoverflow.com/questions/40453859/how-to-get-ehcache-3-1-statistics
-            .using(threadConfig)
-            .with(CacheManagerBuilder.persistence(EhcacheDiskCachingTier.DISK_CACHE_FP))
-            .withCache(cacheAlias, CacheConfigurationBuilder.newCacheConfigurationBuilder(
-                    IndicesRequestCache.Key.class, String.class, ResourcePoolsBuilder.newResourcePoolsBuilder().disk(10, MemoryUnit.MB, false))
-                .withService(listenerConfig) // stackoverflow shows .add(), but IDE says this is deprecated. idk
-            ).build(true);
-        Cache<IndicesRequestCache.Key, String> cache = cacheManager.getCache(cacheAlias, IndicesRequestCache.Key.class, String.class);
+        PersistentCacheManager cacheManager;
+
+        boolean doIntCache = false;
+
+        if (doIntCache) {
+            cacheManager = CacheManagerBuilder.newCacheManagerBuilder()
+                .using(statsService) // https://stackoverflow.com/questions/40453859/how-to-get-ehcache-3-1-statistics
+                .using(threadConfig)
+                .with(CacheManagerBuilder.persistence(EhcacheDiskCachingTier.DISK_CACHE_FP))
+                .withCache(cacheAlias, CacheConfigurationBuilder.newCacheConfigurationBuilder(
+                        Integer.class, String.class, ResourcePoolsBuilder.newResourcePoolsBuilder().disk(10, MemoryUnit.MB, false))
+                    .withService(listenerConfig)
+                ).build(true);
+            Cache<Integer, String> integerCache = cacheManager.getCache(cacheAlias, Integer.class, String.class);
+
+            integerCache.put(0, "blorp");
+            System.out.println("Counter value = " + count.count());
+            String res = integerCache.get(0);
+            System.out.println("Got result " + res);
+            System.out.println("Counter value = " + count.count());
+        } else {
+            cacheManager = CacheManagerBuilder.newCacheManagerBuilder()
+                .using(statsService) // https://stackoverflow.com/questions/40453859/how-to-get-ehcache-3-1-statistics
+                .using(threadConfig)
+                .with(CacheManagerBuilder.persistence(EhcacheDiskCachingTier.DISK_CACHE_FP))
+                .withCache(cacheAlias, CacheConfigurationBuilder.newCacheConfigurationBuilder(
+                        DummySerializableKey.class, String.class, ResourcePoolsBuilder.newResourcePoolsBuilder().disk(10, MemoryUnit.MB, false))
+                    .withService(listenerConfig)
+                ).build(true);
+            Cache<DummySerializableKey, String> cache = cacheManager.getCache(cacheAlias, DummySerializableKey.class, String.class);
+
+            DummySerializableKey key = new DummySerializableKey(Integer.valueOf(0), "blah");
+            cache.put(key, "blorp");
+            System.out.println("Counter value = " + count.count());
+            String res = cache.get(key);
+            System.out.println("Got result " + res);
+            System.out.println("Counter value = " + count.count());
+            TierStatistics ts = statsService.getCacheStatistics(cacheAlias).getTierStatistics().get("Disk");
+            System.out.println("self-reported count = " + ts.getMappings());
+            System.out.println("self-reported misses = " + ts.getMisses());
+            System.out.println("self-reported hits = " + ts.getHits());
+
+            List<Cache.Entry<DummySerializableKey, String>> foos = new ArrayList<>();
+            for(Cache.Entry<DummySerializableKey, String> entry : cache) {
+                foos.add(entry);
+            }
+            int j = 0;
+            j++;
+            System.out.println(j);
+        }
 
-        Directory dir = newDirectory();
+        /*Directory dir = newDirectory();
         IndexWriter writer = new IndexWriter(dir, newIndexWriterConfig());
         writer.addDocument(newDoc(0, "foo"));
         DirectoryReader reader = OpenSearchDirectoryReader.wrap(DirectoryReader.open(writer), new ShardId("foo", "bar", 1));
@@ -216,19 +259,12 @@ public void onRemoval(RemovalNotification<Integer, String> notification) {
         IndicesRequestCache.Key[] keys = new IndicesRequestCache.Key[9];
         TermQueryBuilder termQuery = new TermQueryBuilder("id", "0");
         BytesReference termBytes = XContentHelper.toXContent(termQuery, MediaTypeRegistry.JSON, false);
-        IndicesRequestCache.Key key = new IndicesRequestCache.Key(entity, reader.getReaderCacheHelper().getKey(), termBytes);
-
-        cache.put(key, "blorp");
-        System.out.println("Counter value = " + count.count());
-        String res = cache.get(key);
-        System.out.println("Got result " + res);
+        IndicesRequestCache.Key key = new IndicesRequestCache.Key(entity, reader.getReaderCacheHelper().getKey(), termBytes);*/
 
-        System.out.println("Counter value = " + count.count());
-        //System.out.println("Hits = " + statsService.getCacheStatistics(cacheAlias).getTierStatistics().get("Disk").getHits());
 
         cacheManager.removeCache(cacheAlias);
         cacheManager.close();
-        IOUtils.close(reader, writer, dir);
+        //IOUtils.close(reader, writer, dir);
     }
 
     public void testSpillover() throws Exception {