| // Copyright 2015 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.testing.junit.runner.internal.junit4; |
| |
| import org.junit.runner.Request; |
| import org.junit.runner.Runner; |
| |
| /** |
| * A {@link Request} that memoizies another {@code Request}. |
| */ |
| public class MemoizingRequest extends Request { |
| private final Request requestDelegate; |
| private Runner runnerDelegate; |
| |
| public MemoizingRequest(Request delegate) { |
| this.requestDelegate = delegate; |
| } |
| |
| @Override |
| public final synchronized Runner getRunner() { |
| if (runnerDelegate == null) { |
| runnerDelegate = createRunner(requestDelegate); |
| } |
| return runnerDelegate; |
| } |
| |
| /** |
| * Creates the runner. This method is called at most once. |
| * Subclasses can override this method for different behavior. |
| * The default implementation returns the runner created by the delegate. |
| * |
| * @param delegate request to delegate to |
| * @return runner |
| */ |
| Runner createRunner(Request delegate) { |
| return delegate.getRunner(); |
| } |
| } |