feat(mongo): Optimize the blocking calls of the responsive API (#611)

cosid-mongo/src/main/java/me/ahoo/cosid/mongo/reactive/BlockingAdapter.java

@@ -13,21 +13,15 @@
 
 package me.ahoo.cosid.mongo.reactive;
 
-import me.ahoo.cosid.CosId;
-
 import org.reactivestreams.Publisher;
 import reactor.core.publisher.Mono;
-import reactor.core.scheduler.Scheduler;
-import reactor.core.scheduler.Schedulers;
 
 import java.time.Duration;
-import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 
 public final class BlockingAdapter {
     public static final Duration DEFAULT_TIME_OUT = Duration.ofSeconds(10);
-    private static final Scheduler SCHEDULER = Schedulers.newSingle(CosId.COSID_PREFIX + BlockingAdapter.class.getSimpleName());
 
     private BlockingAdapter() {
     }
@@ -39,17 +33,11 @@ public static <R> R block(Publisher<R> publisher) {
 
     public static <R> R block(Mono<R> mono) {
         try {
-
-            return mono.subscribeOn(SCHEDULER)
-                    .timeout(DEFAULT_TIME_OUT)
-                    .toFuture().get(DEFAULT_TIME_OUT.toMillis(), TimeUnit.MILLISECONDS);
+            BlockingAdapterSubscriber<R> blockingAdapterSubscriber = new BlockingAdapterSubscriber<>();
+            mono.subscribe(blockingAdapterSubscriber);
+            return blockingAdapterSubscriber.block(DEFAULT_TIME_OUT.toMillis(), TimeUnit.MILLISECONDS);
         } catch (InterruptedException | TimeoutException e) {
             throw new RuntimeException(e);
-        } catch (ExecutionException e) {
-            if (e.getCause() instanceof RuntimeException) {
-                throw (RuntimeException) e.getCause();
-            }
-            throw new RuntimeException(e.getCause());
         }
     }
 }

cosid-mongo/src/main/java/me/ahoo/cosid/mongo/reactive/BlockingAdapterSubscriber.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright [2021-present] [ahoo wang <[email protected]> (https://github.com/Ahoo-Wang)].
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package me.ahoo.cosid.mongo.reactive;
+
+import reactor.core.publisher.BaseSubscriber;
+import reactor.core.publisher.SignalType;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
+public class BlockingAdapterSubscriber<T> extends BaseSubscriber<T> {
+    private final CountDownLatch latch;
+
+    private T value;
+    private Throwable error;
+
+    public BlockingAdapterSubscriber() {
+        this.latch = new CountDownLatch(1);
+    }
+
+    @Override
+    protected void hookOnNext(final T value) {
+        this.value = value;
+    }
+
+    @Override
+    protected void hookOnError(Throwable throwable) {
+        this.error = throwable;
+    }
+
+    public T getValue() {
+        return value;
+    }
+
+    public T block(final long timeout, final TimeUnit unit) throws InterruptedException, TimeoutException {
+        return await(timeout, unit).getValue();
+    }
+
+    public Throwable getError() {
+        return error;
+    }
+
+    @Override
+    protected void hookFinally(final SignalType type) {
+        latch.countDown();
+    }
+
+    public BlockingAdapterSubscriber<T> await(final long timeout, final TimeUnit unit) throws TimeoutException, InterruptedException {
+        if (!latch.await(timeout, unit)) {
+            throw new TimeoutException("Timeout after " + timeout + " " + unit);
+        }
+        if (getError() != null) {
+            if (getError() instanceof RuntimeException) {
+                throw (RuntimeException) getError();
+            }
+            throw new RuntimeException(getError());
+        }
+        return this;
+    }
+}