/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.hadoop.test;
import static org.mockito.Mockito.*;
/**
* Helper class to create one-liner stubs, so that instead of: <pre>
* SomeType someDescriptiveMock = mock(SomeType.class);
* when(someDescriptiveMock.someMethod()).thenReturn(someValue);</pre>
* <p>You can now do: <pre>
* SomeType someDescriptiveMock = make(stub(SomeType.class)
* .returning(someValue).from.someMethod());</pre>
*/
public class MockitoMaker {
/**
* Create a mock object from a mocked method call.
*
* @param <T> type of mocked object
* @param methodCall for mocked object
* @return mocked object
*/
@SuppressWarnings("unchecked")
public static <T> T make(Object methodCall) {
StubBuilder<T> sb = StubBuilder.current();
when(methodCall).thenReturn(sb.firstReturn, sb.laterReturns);
return (T) StubBuilder.current().from;
}
/**
* Create a stub builder of a mocked object.
*
* @param <T> type of the target object to be mocked
* @param target class of the target object to be mocked
* @return the stub builder of the mocked object
*/
public static <T> StubBuilder<T> stub(Class<T> target) {
return new StubBuilder<T>(mock(target));
}
/**
* Builder class for stubs
* @param <T> type of the object to be mocked
*/
public static class StubBuilder<T> {
/**
* The target mock object
*/
public final T from;
// We want to be able to use this even when the tests are run in parallel.
@SuppressWarnings("rawtypes")
private static final ThreadLocal<StubBuilder> tls =
new ThreadLocal<StubBuilder>() {
@Override protected StubBuilder initialValue() {
return new StubBuilder();
}
};
private Object firstReturn = null;
private Object[] laterReturns = {};
/**
* Default constructor for the initial stub builder
*/
public StubBuilder() {
this.from = null;
}
/**
* Construct a stub builder with a mock instance
*
* @param mockInstance the mock object
*/
public StubBuilder(T mockInstance) {
tls.set(this);
this.from = mockInstance;
}
/**
* Get the current stub builder from thread local
*
* @param <T>
* @return the stub builder of the mocked object
*/
@SuppressWarnings("unchecked")
public static <T> StubBuilder<T> current() {
return tls.get();
}
/**
* Set the return value for the current stub builder
*
* @param value the return value
* @return the stub builder
*/
public StubBuilder<T> returning(Object value) {
this.firstReturn = value;
return this;
}
/**
* Set the return values for the current stub builder
*
* @param value the first return value
* @param values the return values for later invocations
* @return the stub builder
*/
public StubBuilder<T> returning(Object value, Object... values) {
this.firstReturn = value;
this.laterReturns = values;
return this;
}
}
}