Implemented ClientBuilderListener

Signed-off-by: jansupol <jan.supol@oracle.com>

core-client/src/main/java/org/glassfish/jersey/client/JerseyClientBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2019 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2020 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -17,6 +17,9 @@
 package org.glassfish.jersey.client;
 
 import java.security.KeyStore;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.ScheduledExecutorService;
@@ -30,8 +33,12 @@
 
 import org.glassfish.jersey.SslConfigurator;
 import org.glassfish.jersey.client.internal.LocalizationMessages;
+import org.glassfish.jersey.client.spi.ClientBuilderListener;
+import org.glassfish.jersey.internal.ServiceFinder;
 import org.glassfish.jersey.internal.util.collection.UnsafeValue;
 import org.glassfish.jersey.internal.util.collection.Values;
+import org.glassfish.jersey.model.internal.RankedComparator;
+import org.glassfish.jersey.model.internal.RankedProvider;
 
 /**
  * Jersey provider of {@link javax.ws.rs.client.ClientBuilder JAX-RS client builder}.
@@ -45,6 +52,23 @@ public class JerseyClientBuilder extends ClientBuilder {
     private SslConfigurator sslConfigurator;
     private SSLContext sslContext;
 
+    private static final List<ClientBuilderListener> CLIENT_BUILDER_LISTENERS;
+
+    static {
+        final List<RankedProvider<ClientBuilderListener>> listeners = new LinkedList<>();
+        for (ClientBuilderListener listener : ServiceFinder.find(ClientBuilderListener.class)) {
+            listeners.add(new RankedProvider<>(listener));
+        }
+        listeners.sort(new RankedComparator<>(RankedComparator.Order.ASCENDING));
+
+        final List<ClientBuilderListener> sortedList = new LinkedList<>();
+        for (RankedProvider<ClientBuilderListener> listener : listeners) {
+            sortedList.add(listener.getProvider());
+        }
+
+        CLIENT_BUILDER_LISTENERS = Collections.unmodifiableList(sortedList);
+    }
+
     /**
      * Create a new custom-configured {@link JerseyClient} instance.
      *
@@ -72,6 +96,14 @@ public static JerseyClient createClient(Configuration configuration) {
      */
     public JerseyClientBuilder() {
         this.config = new ClientConfig();
+
+        init(this);
+    }
+
+    private static void init(ClientBuilder builder) {
+        for (ClientBuilderListener listener : CLIENT_BUILDER_LISTENERS) {
+            listener.onNewBuilder(builder);
+        }
     }
 
     @Override

core-client/src/main/java/org/glassfish/jersey/client/spi/ClientBuilderListener.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2020 Oracle and/or its affiliates. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0, which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the
+ * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
+ * version 2 with the GNU Classpath Exception, which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ */
+
+package org.glassfish.jersey.client.spi;
+
+import org.glassfish.jersey.Beta;
+
+import javax.ws.rs.client.ClientBuilder;
+
+/**
+ * <p>
+ * Implementations of this interface will be notified when new ClientBuilder
+ * instances are being constructed.  This will allow implementations to register
+ * providers on the ClientBuilder, and is intended for global providers.
+ * </p>
+ * <p>
+ * In order for the ClientBuilder to call implementations of this interface,
+ * the implementation must be specified such that a ServiceLoader can find it -
+ * i.e. it must be specified in the <code>
+ * META-INF/services/org.glassfish.jersey.client.spi.ClientBuilderListener
+ * </code> file in an archive on the current thread's context classloader's
+ * class path.
+ * </p>
+ * <p>
+ * Note that the <code>onNewBuilder</code> method will be called when the
+ * ClientBuilder is constructed, not when it's <code>build</code> method is
+ * invoked.  This allows the caller to override global providers if they desire.
+ * </p>
+ * <p>
+ * The ClientBuilderListener are invoked in an order given by it's {@code @Priority}.
+ * The default is {@code Priorities.USER}.
+ * </p>
+ * @since 2.32
+ */
+// Must not be annotated with @Contract
+@Beta
+public interface ClientBuilderListener {
+    void onNewBuilder(ClientBuilder builder);
+}

core-client/src/test/java/org/glassfish/jersey/client/spi/ClientBuilderListenerTest.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2020 Oracle and/or its affiliates. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0, which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the
+ * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
+ * version 2 with the GNU Classpath Exception, which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ */
+
+package org.glassfish.jersey.client.spi;
+
+import org.glassfish.jersey.client.ClientConfig;
+import org.junit.Assert;
+import org.junit.Test;
+
+import javax.annotation.Priority;
+import javax.ws.rs.Priorities;
+import javax.ws.rs.client.Client;
+import javax.ws.rs.client.ClientBuilder;
+
+public class ClientBuilderListenerTest {
+
+    public static final String PROPERTY_NAME = "ClientBuilderListenerProperty";
+
+    @Priority(Priorities.USER + 1000)
+    public static class FirstClientBuilderListener implements ClientBuilderListener {
+        @Override
+        public void onNewBuilder(ClientBuilder builder) {
+            builder.withConfig(new ClientConfig().property(PROPERTY_NAME, 60));
+        }
+    }
+
+    public static class SecondClientBuilderListener implements ClientBuilderListener {
+        @Override
+        public void onNewBuilder(ClientBuilder builder) {
+            builder.withConfig(new ClientConfig().property(PROPERTY_NAME, 50));
+        }
+    }
+
+    @Priority(Priorities.USER + 2000)
+    public static class ThirdClientBuilderListener implements ClientBuilderListener {
+        @Override
+        public void onNewBuilder(ClientBuilder builder) {
+            builder.withConfig(new ClientConfig().property(PROPERTY_NAME, 70));
+        }
+    }
+
+    @Test
+    public void testClientBuilderListener() {
+        Client client = ClientBuilder.newClient();
+        Assert.assertEquals(70, client.getConfiguration().getProperty(PROPERTY_NAME));
+    }
+
+}

core-client/src/test/resources/META-INF/services/org.glassfish.jersey.client.spi.ClientBuilderListener

@@ -0,0 +1,3 @@
+org.glassfish.jersey.client.spi.ClientBuilderListenerTest$ThirdClientBuilderListener
+org.glassfish.jersey.client.spi.ClientBuilderListenerTest$FirstClientBuilderListener
+org.glassfish.jersey.client.spi.ClientBuilderListenerTest$SecondClientBuilderListener