Add .loadIntegrations() method to builder

agent/src/main/java/reactor/blockhound/BlockHound.java

@@ -85,13 +85,9 @@ public static Builder builder() {
      * @see BlockHound#builder()
      */
     public static void install(BlockHoundIntegration... integrations) {
-        Builder builder = builder();
-        ServiceLoader<BlockHoundIntegration> serviceLoader = ServiceLoader.load(BlockHoundIntegration.class);
-        Stream
-                .concat(StreamSupport.stream(serviceLoader.spliterator(), false), Stream.of(integrations))
-                .sorted()
-                .forEach(builder::with);
-        builder.install();
+        builder()
+                .loadIntegrationsAndProvided(integrations)
+                .install();
     }
 
     private BlockHound() {
@@ -354,6 +350,30 @@ public Builder with(BlockHoundIntegration integration) {
             return this;
         }
 
+        /**
+         * Loads integrations from classpath with {@link ServiceLoader}
+         * @return this
+         */
+        public Builder loadIntegrations() {
+            return loadIntegrationsAndProvided();
+        }
+
+        /**
+         * Loads integrations from classpath with {@link ServiceLoader} together with the provided integrations
+         * in sorted order
+         *
+         * @param providedIntegrations an array of integrations to automatically apply together with the integrations from the classpath
+         * @return this
+         */
+        Builder loadIntegrationsAndProvided(BlockHoundIntegration... providedIntegrations) {
+            ServiceLoader<BlockHoundIntegration> serviceLoader = ServiceLoader.load(BlockHoundIntegration.class);
+            Stream
+                    .concat(StreamSupport.stream(serviceLoader.spliterator(), false), Stream.of(providedIntegrations))
+                    .sorted()
+                    .forEach(this::with);
+            return this;
+        }
+
         Builder() {
         }
 

example/src/test/java/com/example/BuilderLoadIntegrationsTest.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2018-2019 Pivotal Software Inc, All Rights Reserved.
+ *
+ * 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
+ *
+ *        https://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 com.example;
+
+import org.junit.Test;
+import reactor.blockhound.BlockHound;
+import reactor.blockhound.BlockingOperationError;
+import reactor.core.publisher.Mono;
+import reactor.core.scheduler.Schedulers;
+
+import java.util.Objects;
+
+public class BuilderLoadIntegrationsTest {
+
+    static {
+        BlockHound.builder()
+                .loadIntegrations()
+                .install();
+    }
+
+    @Test(expected = BlockingOperationError.class)
+    public void shouldLoadIntegrations() throws Throwable {
+        try {
+            Mono.fromCallable(() -> {
+                Thread.sleep(1);
+                return "";
+            }).subscribeOn(Schedulers.parallel()).block();
+        } catch (Exception e) {
+            throw Objects.requireNonNull(e.getCause());
+        }
+    }
+}