1 files changed, 68 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaToolchainProvider.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaToolchainProvider.java
new file mode 100644
index 0000000000..3e210d8fbd
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaToolchainProvider.java
@@ -0,0 +1,68 @@
+// Copyright 2014 Google 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
+//
+// 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.rules.java;
+
+import com.google.common.collect.ImmutableList;
+import com.google.devtools.build.lib.analysis.RuleConfiguredTarget.Mode;
+import com.google.devtools.build.lib.analysis.RuleContext;
+import com.google.devtools.build.lib.analysis.TransitiveInfoProvider;
+import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
+
+import java.util.List;
+
+/**
+ * Information about the JDK used by the <code>java_*</code> rules.
+ */
+@Immutable
+public final class JavaToolchainProvider implements TransitiveInfoProvider {
+
+  private final ImmutableList<String> javacOptions;
+
+  public JavaToolchainProvider(String source, String target, String encoding,
+      ImmutableList<String> xlint, ImmutableList<String> misc, List<String> defaultJavacFlags) {
+    super();
+    // merges the defaultJavacFlags from
+    // {@link JavaConfiguration} with the flags from the {@code java_toolchain} rule.
+    JavaToolchainData data = new JavaToolchainData(source, target, encoding, xlint, misc);
+    this.javacOptions = ImmutableList.<String>builder()
+        .addAll(data.getJavacOptions())
+        .addAll(defaultJavacFlags)
+        .build();
+  }
+
+  /**
+   * @return the list of default options for the java compiler
+   */
+  public ImmutableList<String> getJavacOptions() {
+    return javacOptions;
+  }
+
+  /**
+   * An helper method to construct the list of javac options.
+   *
+   * @param ruleContext The rule context of the current rule.
+   * @return the list of flags provided by the {@code java_toolchain} rule merged with the one
+   *         provided by the {@link JavaConfiguration} fragment.
+   */
+  public static List<String> getDefaultJavacOptions(RuleContext ruleContext) {
+    JavaToolchainProvider javaToolchain =
+        ruleContext.getPrerequisite(":java_toolchain", Mode.TARGET, JavaToolchainProvider.class);
+    if (javaToolchain == null) {
+      ruleContext.ruleError("No java_toolchain implicit dependency found. This is probably because"
+          + " your java configuration is not up-to-date.");
+      return ImmutableList.of();
+    }
+    return javaToolchain.getJavacOptions();
+  }
+}