// 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();
}
}