Refactor the module API to use the builder pattern for executor creation.

This significantly simplifies several of our modules.

--
MOS_MIGRATED_REVID=137713119

2 files changed, 66 insertions, 12 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/actions/ExecutorBuilder.java b/src/main/java/com/google/devtools/build/lib/actions/ExecutorBuilder.java
new file mode 100644
index 0000000000..c25fc07245
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/actions/ExecutorBuilder.java
@@ -0,0 +1,64 @@
+// Copyright 2016 The Bazel Authors. 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
+//
+//    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 com.google.devtools.build.lib.actions;
+
+import com.google.common.collect.ImmutableList;
+import com.google.devtools.build.lib.actions.Executor.ActionContext;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Builder class to create an {@link Executor} instance. This class is part of the module API,
+ * which allows modules to affect how the executor is initialized.
+ */
+public class ExecutorBuilder {
+  private final List<ActionContextProvider> actionContextProviders = new ArrayList<>();
+  private final List<ActionContextConsumer> actionContextConsumers = new ArrayList<>();
+
+  // These methods shouldn't be public, but they have to be right now as ExecutionTool is in another
+  // package.
+  public ImmutableList<ActionContextProvider> getActionContextProviders() {
+    return ImmutableList.copyOf(actionContextProviders);
+  }
+
+  public ImmutableList<ActionContextConsumer> getActionContextConsumers() {
+    return ImmutableList.copyOf(actionContextConsumers);
+  }
+
+  /**
+   * Adds the specified action context providers to the executor.
+   */
+  public ExecutorBuilder addActionContextProvider(ActionContextProvider provider) {
+    this.actionContextProviders.add(provider);
+    return this;
+  }
+
+  /**
+   * Adds the specified action context to the executor, by wrapping it in a simple action context
+   * provider implementation.
+   */
+  public ExecutorBuilder addActionContext(ActionContext context) {
+    return addActionContextProvider(new SimpleActionContextProvider(context));
+  }
+
+  /**
+   * Adds the specified action context consumer to the executor.
+   */
+  public ExecutorBuilder addActionContextConsumer(ActionContextConsumer consumer) {
+    this.actionContextConsumers.add(consumer);
+    return this;
+  }
+
+}
+
diff --git a/src/main/java/com/google/devtools/build/lib/actions/SimpleActionContextProvider.java b/src/main/java/com/google/devtools/build/lib/actions/SimpleActionContextProvider.java
index 1239ccb0f9..642bc09ada 100644
--- a/src/main/java/com/google/devtools/build/lib/actions/SimpleActionContextProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/actions/SimpleActionContextProvider.java
@@ -15,25 +15,15 @@ package com.google.devtools.build.lib.actions;
 
 import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.lib.actions.Executor.ActionContext;
-
 import java.util.List;
 
 /**
  * An {@link ActionContextProvider} that just provides the {@link ActionContext}s it's given.
  */
-public class SimpleActionContextProvider extends ActionContextProvider {
-
-  /**
-   * Creates an immutable list containing a single SimpleActionContextProvider with the given
-   * contexts as a convenience for BlazeModule.getActionContextProviders().
-   */
-  public static List<ActionContextProvider> of(ActionContext ... contexts) {
-    return ImmutableList.<ActionContextProvider>of(new SimpleActionContextProvider(contexts));
-  }
-
+final class SimpleActionContextProvider extends ActionContextProvider {
   private final List<ActionContext> actionContexts;
 
-  public SimpleActionContextProvider(ActionContext ... contexts) {
+  public SimpleActionContextProvider(ActionContext... contexts) {
     actionContexts = ImmutableList.<ActionContext>copyOf(contexts);
   }