/*
* Copyright © 2015 Cask Data, Inc.
*
* 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 co.cask.cdap.test;
import org.junit.rules.ExternalResource;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicInteger;
/**
* An {@link ExternalResource} that maintain a singleton to another {@link ExternalResource} so that
* it can be used in test suite as well as in individual test in the suite.
*/
public class SingletonExternalResource extends ExternalResource {
private static final AtomicInteger INSTANCES = new AtomicInteger(0);
private final ExternalResource externalResource;
public SingletonExternalResource(ExternalResource externalResource) {
this.externalResource = externalResource;
}
@Override
protected void before() throws Throwable {
if (INSTANCES.getAndIncrement() == 0) {
Method before = ExternalResource.class.getDeclaredMethod("before");
before.setAccessible(true);
try {
before.invoke(externalResource);
} catch (InvocationTargetException e) {
throw e.getCause();
}
}
}
@Override
protected void after() {
if (INSTANCES.decrementAndGet() == 0) {
try {
Method after = ExternalResource.class.getDeclaredMethod("after");
after.setAccessible(true);
after.invoke(externalResource);
} catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
// Should not happen
throw new RuntimeException(e);
}
}
}
/**
* Returns the underlying {@link ExternalResource}.
*
* @param <T> The actual type of the resource.
*/
@SuppressWarnings("unchecked")
public <T extends ExternalResource> T get() {
Objects.requireNonNull(externalResource);
return (T) externalResource;
}
}