[Grid] Add support for customizing the Grid Registry

- Make the grid registry an interface -- GridRegistry.
- Introduce BaseGridRegistry which is intended to be extended by
  GridRegistry implementations.
- Introduce DefaultGridRegistry which replaces the pre-existing
  (now deprecated) Registry class. Most of the _real_ code from Registry
  was moved to DefaultGridRegistry.
- Deprecated Registry. Replaced underlying implementation of new
  DefaultGridRegistry. Also make Registry implement GridRegistry.
  Changes here intended to ease migration and allow old
  code paths to continue to compile/work in the interim.
- Change the return type to T extends GridRegistry for some methods.
- Increase visibility of some additional methods and/or types which the
  existing DefaultGridRegistry takes advantage of -- allowing reuse.
- Add 'registryClass' arugment to '-role hub' for specifying custom
  registry implmentation on the CLASSPATH
- Update test code to use DefaultGridRegistry and GridRegistry

java/server/src/org/openqa/grid/common/defaults/DefaultHub.json

@@ -5,6 +5,7 @@
   "withoutServlets": [],
   "custom": {},
   "capabilityMatcher": "org.openqa.grid.internal.utils.DefaultCapabilityMatcher",
+  "registryClass": "org.openqa.grid.internal.DefaultGridRegistry",
   "throwOnCapabilityNotPresent": true,
   "cleanUpCycle": 5000,
   "role": "hub",

java/server/src/org/openqa/grid/internal/ActiveTestSessions.java

@@ -34,7 +34,7 @@
  * The set of active test sessions.
  */
 @ThreadSafe
-class ActiveTestSessions {
+public class ActiveTestSessions {
 
   private static final Logger log = Logger.getLogger(ActiveTestSessions.class.getName());
 

java/server/src/org/openqa/grid/internal/BaseGridRegistry.java

@@ -0,0 +1,73 @@
+// Licensed to the Software Freedom Conservancy (SFC) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The SFC licenses this file
+// to you 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 org.openqa.grid.internal;
+
+import org.openqa.grid.internal.utils.configuration.GridHubConfiguration;
+import org.openqa.grid.web.Hub;
+import org.openqa.selenium.remote.internal.HttpClientFactory;
+
+public abstract class BaseGridRegistry implements GridRegistry {
+  protected final HttpClientFactory httpClientFactory;
+  @Deprecated
+  protected GridHubConfiguration configuration;
+
+  // The following needs to be volatile because we expose a public setters
+  protected volatile Hub hub;
+
+  public BaseGridRegistry(Hub hub) {
+    this.httpClientFactory = new HttpClientFactory();
+    this.hub = hub;
+
+    this.configuration = (hub != null) ?
+       hub.getConfiguration() : new GridHubConfiguration();
+  }
+
+  /**
+   * @see GridRegistry#getConfiguration()
+   */
+  @Deprecated
+  public GridHubConfiguration getConfiguration() {
+    return (hub != null) ? hub.getConfiguration() :
+           (configuration != null) ? configuration : new GridHubConfiguration();
+  }
+
+  /**
+   * @see GridRegistry#getHub()
+   */
+  public Hub getHub() {
+    return hub;
+  }
+
+  /**
+   * @see GridRegistry#setHub(Hub)
+   */
+  public void setHub(Hub hub) {
+    this.hub = hub;
+    if (hub != null) {
+      this.configuration = hub.getConfiguration();
+    }
+  }
+
+  /**
+   * @see GridRegistry#getHttpClientFactory()
+   */
+  public HttpClientFactory getHttpClientFactory() {
+    return httpClientFactory;
+  }
+
+}

java/server/src/org/openqa/grid/internal/BaseRemoteProxy.java

@@ -33,11 +33,11 @@
 import org.openqa.grid.common.exception.GridException;
 import org.openqa.grid.internal.listeners.TimeoutListener;
 import org.openqa.grid.internal.utils.CapabilityMatcher;
+import org.openqa.grid.internal.utils.DefaultCapabilityMatcher;
 import org.openqa.grid.internal.utils.DefaultHtmlRenderer;
 import org.openqa.grid.internal.utils.HtmlRenderer;
 import org.openqa.grid.internal.utils.configuration.GridNodeConfiguration;
 import org.openqa.selenium.MutableCapabilities;
-import org.openqa.selenium.remote.DesiredCapabilities;
 import org.openqa.selenium.remote.internal.HttpClientFactory;
 
 import java.io.BufferedReader;
@@ -69,8 +69,9 @@ public class BaseRemoteProxy implements RemoteProxy {
   // list of the type of test the remote can run.
   private final List<TestSlot> testSlots;
 
-  private final Registry registry;
+  private final GridRegistry registry;
 
+  private CapabilityMatcher capabilityMatcher;
 
   private final String id;
 
@@ -81,12 +82,12 @@ public List<TestSlot> getTestSlots() {
     return testSlots;
   }
 
-  public Registry getRegistry() {
-    return registry;
+  public <T extends GridRegistry> T getRegistry() {
+    return (T) registry;
   }
 
   public CapabilityMatcher getCapabilityHelper() {
-    return registry.getConfiguration().capabilityMatcher;
+    return capabilityMatcher;
   }
 
 
@@ -99,12 +100,16 @@ public CapabilityMatcher getCapabilityHelper() {
    * @param request  The request
    * @param registry The registry to use
    */
-  public BaseRemoteProxy(RegistrationRequest request, Registry registry) {
+  public BaseRemoteProxy(RegistrationRequest request, GridRegistry registry) {
     this.request = request;
     this.registry = registry;
     this.config = new GridNodeConfiguration();
-    // the registry is the 'hub' configuration, which is used as a seed.
-    this.config.merge(registry.getConfiguration());
+    this.capabilityMatcher = new DefaultCapabilityMatcher();
+    // the registry is the 'hub' configuration, which is used as a seed for this proxy configuration
+    if (registry.getHub() != null) {
+      this.config.merge(registry.getHub().getConfiguration());
+      this.capabilityMatcher = registry.getHub().getConfiguration().capabilityMatcher;
+    }
     // the proxy values must override any that the hub specify where an overlap occurs.
     // merging last causes the values to be overridden.
     this.config.merge(request.getConfiguration());
@@ -137,7 +142,7 @@ public BaseRemoteProxy(RegistrationRequest request, Registry registry) {
       this.id = remoteHost.toExternalForm();
     }
 
-    List<MutableCapabilities>capabilities = request.getConfiguration().capabilities;
+    List<MutableCapabilities> capabilities = request.getConfiguration().capabilities;
 
     List<TestSlot> slots = new ArrayList<>();
     for (MutableCapabilities capability : capabilities) {
@@ -336,7 +341,7 @@ public boolean isBusy() {
    */
   @SuppressWarnings("unchecked")
   public static <T extends RemoteProxy> T getNewInstance(
-      RegistrationRequest request, Registry registry) {
+      RegistrationRequest request, GridRegistry registry) {
     try {
       String proxyClass = request.getConfiguration().proxy;
       if (proxyClass == null) {
@@ -346,7 +351,7 @@ public static <T extends RemoteProxy> T getNewInstance(
       Class<?> clazz = Class.forName(proxyClass);
       log.fine("Using class " + clazz.getName());
       Object[] args = new Object[]{request, registry};
-      Class<?>[] argsClass = new Class[]{RegistrationRequest.class, Registry.class};
+      Class<?>[] argsClass = new Class[]{RegistrationRequest.class, GridRegistry.class};
       Constructor<?> c = clazz.getConstructor(argsClass);
       Object proxy = c.newInstance(args);
       if (proxy instanceof RemoteProxy) {