support jackson buffer recycler

http-marshallers-java/http-jackson/src/main/java/org/apache/pekko/http/javadsl/marshallers/jackson/Jackson.java

@@ -30,6 +30,9 @@
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.core.StreamReadConstraints;
 import com.fasterxml.jackson.core.StreamWriteConstraints;
+import com.fasterxml.jackson.core.util.BufferRecycler;
+import com.fasterxml.jackson.core.util.JsonRecyclerPools;
+import com.fasterxml.jackson.core.util.RecyclerPool;
 import com.fasterxml.jackson.databind.MapperFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.json.JsonMapper;
@@ -113,7 +116,28 @@ static ObjectMapper createMapper(final Config config) {
         JsonFactory.builder()
             .streamReadConstraints(streamReadConstraints)
             .streamWriteConstraints(streamWriteConstraints)
+            .recyclerPool(getBufferRecyclerPool(config))
             .build();
     return new JsonMapper(jsonFactory);
   }
+
+  private static RecyclerPool<BufferRecycler> getBufferRecyclerPool(final Config cfg) {
+    switch (cfg.getString("buffer-recycler.pool-instance")) {
+      case "thread-local":
+        return JsonRecyclerPools.threadLocalPool();
+      case "lock-free":
+        return JsonRecyclerPools.newLockFreePool();
+      case "shared-lock-free":
+        return JsonRecyclerPools.sharedLockFreePool();
+      case "concurrent-deque":
+        return JsonRecyclerPools.newConcurrentDequePool();
+      case "shared-concurrent-deque":
+        return JsonRecyclerPools.sharedConcurrentDequePool();
+      case "bounded":
+        return JsonRecyclerPools.newBoundedPool(cfg.getInt("buffer-recycler.bounded-pool-size"));
+      default:
+        throw new IllegalArgumentException(
+            "Unknown recycler-pool: " + cfg.getString("buffer-recycler.pool-instance"));
+    }
+  }
 }

http-marshallers-java/http-jackson/src/main/resources/reference.conf

@@ -9,7 +9,7 @@
 
 pekko.http.marshallers.jackson {
   read {
-    # see https://www.javadoc.io/static/com.fasterxml.jackson.core/jackson-core/2.16.1/com/fasterxml/jackson/core/StreamReadConstraints.html
+    # see https://www.javadoc.io/static/com.fasterxml.jackson.core/jackson-core/2.16.2/com/fasterxml/jackson/core/StreamReadConstraints.html
     # these defaults are the same as the defaults in `StreamReadConstraints`
     max-nesting-depth = 1000
     max-number-length = 1000
@@ -20,8 +20,20 @@ pekko.http.marshallers.jackson {
   }
 
   write {
-    # see https://www.javadoc.io/static/com.fasterxml.jackson.core/jackson-core/2.16.1/com/fasterxml/jackson/core/StreamWriteConstraints.html
+    # see https://www.javadoc.io/static/com.fasterxml.jackson.core/jackson-core/2.16.2/com/fasterxml/jackson/core/StreamWriteConstraints.html
     # these defaults are the same as the defaults in `StreamWriteConstraints`
     max-nesting-depth = 1000
   }
+
+  # Controls the Buffer Recycler Pool implementation used by Jackson.
+  # https://javadoc.io/static/com.fasterxml.jackson.core/jackson-core/2.16.2/com/fasterxml/jackson/core/util/JsonRecyclerPools.html
+  # The default is "thread-local" which is the same as the default in Jackson 2.16.
+  buffer-recycler {
+    # the supported values are "thread-local", "lock-free", "shared-lock-free", "concurrent-deque",
+    # "shared-concurrent-deque", "bounded"
+    pool-instance = "thread-local"
+    # the maximum size of bounded recycler pools - must be >=1 or an IllegalArgumentException will occur
+    # only applies to pool-instance type "bounded"
+    bounded-pool-size = 100
+  }
 }

http-marshallers-java/http-jackson/src/test/java/org/apache/pekko/http/javadsl/marshallers/jackson/JacksonTest.java

@@ -17,6 +17,9 @@
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.core.StreamReadConstraints;
 import com.fasterxml.jackson.core.StreamWriteConstraints;
+import com.fasterxml.jackson.core.util.BufferRecycler;
+import com.fasterxml.jackson.core.util.JsonRecyclerPools.BoundedPool;
+import com.fasterxml.jackson.core.util.RecyclerPool;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.typesafe.config.Config;
 import com.typesafe.config.ConfigFactory;
@@ -107,9 +110,7 @@ public void configStreamReadsConstraints() throws Exception {
             + "\n"
             + "read.max-nesting-depth="
             + maxNestingDepth;
-    Config config =
-        ConfigFactory.parseString(configText)
-            .withFallback(ConfigFactory.load().getConfig("pekko.http.marshallers.jackson"));
+    Config config = ConfigFactory.parseString(configText).withFallback(getDefaultConfig());
     ObjectMapper mapper = Jackson.createMapper(config);
     StreamReadConstraints constraints = mapper.getFactory().streamReadConstraints();
     assertEquals(maxNumLen, constraints.getMaxNumberLength());
@@ -123,11 +124,36 @@ public void configStreamReadsConstraints() throws Exception {
   public void configStreamWritesConstraints() throws Exception {
     final int maxNestingDepth = 5;
     String configText = "write.max-nesting-depth=" + maxNestingDepth;
-    Config config =
-        ConfigFactory.parseString(configText)
-            .withFallback(ConfigFactory.load().getConfig("pekko.http.marshallers.jackson"));
+    Config config = ConfigFactory.parseString(configText).withFallback(getDefaultConfig());
     ObjectMapper mapper = Jackson.createMapper(config);
     StreamWriteConstraints constraints = mapper.getFactory().streamWriteConstraints();
     assertEquals(maxNestingDepth, constraints.getMaxNestingDepth());
   }
+
+  @Test
+  public void testDefaultFactory() throws Exception {
+    ObjectMapper mapper = Jackson.createMapper(getDefaultConfig());
+    RecyclerPool<BufferRecycler> recyclerPool = mapper.getFactory()._getRecyclerPool();
+    assertEquals("ThreadLocalPool", recyclerPool.getClass().getSimpleName());
+  }
+
+  @Test
+  public void testFactoryWithBufferRecyclerSetting() throws Exception {
+    final String poolType = "bounded";
+    final int poolSize = 10;
+    String configText =
+        "buffer-recycler.pool-instance="
+            + poolType
+            + "\nbuffer-recycler.bounded-pool-size="
+            + poolSize;
+    Config config = ConfigFactory.parseString(configText).withFallback(getDefaultConfig());
+    ObjectMapper mapper = Jackson.createMapper(config);
+    RecyclerPool<BufferRecycler> recyclerPool = mapper.getFactory()._getRecyclerPool();
+    assertEquals("BoundedPool", recyclerPool.getClass().getSimpleName());
+    assertEquals(poolSize, ((BoundedPool) recyclerPool).capacity());
+  }
+
+  private static Config getDefaultConfig() {
+    return ConfigFactory.load().getConfig("pekko.http.marshallers.jackson");
+  }
 }