/*
* Copyright (c) 2007 Mockito contributors
* This program is made available under the terms of the MIT License.
*/
package org.mockito;
import org.mockito.internal.stubbing.answers.ReturnsArgumentAt;
import org.mockito.internal.stubbing.answers.ReturnsElementsOf;
import org.mockito.internal.stubbing.defaultanswers.ForwardsInvocations;
import org.mockito.stubbing.Answer;
import java.util.Collection;
/**
* Additional answers provides factory methods for less common answers.
*
* <p>Currently offer answers that can return the parameter of an invocation at a certain position.
*
* <p>See factory methods for more information : {@link #returnsFirstArg}, {@link #returnsSecondArg},
* {@link #returnsLastArg} and {@link #returnsArgAt}
*
* @since 1.9.5
*/
@SuppressWarnings("unchecked")
public class AdditionalAnswers {
private static final ReturnsArgumentAt RETURNS_FIRST_ARGUMENT = new ReturnsArgumentAt(0);
private static final ReturnsArgumentAt RETURNS_SECOND_ARGUMENT = new ReturnsArgumentAt(1);
private static final ReturnsArgumentAt RETURNS_LAST_ARGUMENT = new ReturnsArgumentAt(-1);
/**
* Returns the first parameter of an invocation.
*
* <p>
* This additional answer could be used at stub time using the
* <code>then|do|will{@link org.mockito.stubbing.Answer}</code> methods. For example :
* </p>
*
* <pre class="code"><code class="java">given(carKeyFob.authenticate(carKey)).will(returnsFirstArg());
* doAnswer(returnsFirstArg()).when(carKeyFob).authenticate(carKey)</code></pre>
*
* @param <T> Return type of the invocation.
* @return Answer that will return the first argument of the invocation.
*
* @since 1.9.5
*/
public static <T> Answer<T> returnsFirstArg() {
return (Answer<T>) RETURNS_FIRST_ARGUMENT;
}
/**
* Returns the second parameter of an invocation.
*
* <p>
* This additional answer could be used at stub time using the
* <code>then|do|will{@link org.mockito.stubbing.Answer}</code> methods. For example :
* </p>
*
* <pre class="code"><code class="java">given(trader.apply(leesFormula, onCreditDefaultSwap)).will(returnsSecondArg());
* doAnswer(returnsSecondArg()).when(trader).apply(leesFormula, onCreditDefaultSwap)</code></pre>
*
* @param <T> Return type of the invocation.
* @return Answer that will return the second argument of the invocation.
*
* @since 1.9.5
*/
public static <T> Answer<T> returnsSecondArg() {
return (Answer<T>) RETURNS_SECOND_ARGUMENT;
}
/**
* Returns the last parameter of an invocation.
*
* <p>
* This additional answer could be used at stub time using the
* <code>then|do|will{@link org.mockito.stubbing.Answer}</code> methods. For example :
* </p>
*
* <pre class="code"><code class="java">given(person.remember(dream1, dream2, dream3, dream4)).will(returnsLastArg());
* doAnswer(returnsLastArg()).when(person).remember(dream1, dream2, dream3, dream4)</code></pre>
*
* @param <T> Return type of the invocation.
* @return Answer that will return the last argument of the invocation.
*
* @since 1.9.5
*/
public static <T> Answer<T> returnsLastArg() {
return (Answer<T>) RETURNS_LAST_ARGUMENT;
}
/**
* Returns the parameter of an invocation at the given position.
*
* <p>
* This additional answer could be used at stub time using the
* <code>then|do|will{@link org.mockito.stubbing.Answer}</code> methods. For example :
* </p>
*
* <pre class="code"><code class="java">given(person.remember(dream1, dream2, dream3, dream4)).will(returnsArgAt(3));
* doAnswer(returnsArgAt(3)).when(person).remember(dream1, dream2, dream3, dream4)</code></pre>
*
* @param <T> Return type of the invocation.
* @param position index of the argument from the list of arguments.
* @return Answer that will return the argument from the given position in the argument's list
*
* @since 1.9.5
*/
public static <T> Answer<T> returnsArgAt(int position) {
return (Answer<T>) new ReturnsArgumentAt(position);
}
/**
* An answer that directly forwards the calls to the delegate. The delegate may or may not be of the same type as the mock.
* If the type is different, a matching method needs to be found on delegate type otherwise an exception is thrown.
* <p>
* Useful for spies or partial mocks of objects that are difficult to mock
* or spy using the usual spy API. Possible use cases:
* <ul>
* <li>Final classes but with an interface</li>
* <li>Already custom proxied object</li>
* <li>Special objects with a finalize method, i.e. to avoid executing it 2 times</li>
* </ul>
* For more details including the use cases reported by users take a look at
* <a link="http://code.google.com/p/mockito/issues/detail?id=145">issue 145</a>.
* <p>
* The difference with the regular spy:
* <ul>
* <li>
* The regular spy ({@link Mockito#spy(Object)}) contains <strong>all</strong> state from the spied instance
* and the methods are invoked on the spy. The spied instance is only used at mock creation to copy the state from.
* If you call a method on a regular spy and it internally calls other methods on this spy, those calls are remembered
* for verifications, and they can be effectively stubbed.
* </li>
* <li>
* The mock that delegates simply delegates all methods to the delegate.
* The delegate is used all the time as methods are delegated onto it.
* If you call a method on a mock that delegates and it internally calls other methods on this mock,
* those calls are <strong>not</strong> remembered for verifications, stubbing does not have effect on them, too.
* Mock that delegates is less powerful than the regular spy but it is useful when the regular spy cannot be created.
* </li>
* </ul>
* An example with a final class that we want to delegate to:
* <p>
* <pre class="code"><code class="java">
* final class DontYouDareToMockMe implements list { ... }
*
* DontYouDareToMockMe awesomeList = new DontYouDareToMockMe();
*
* List mock = mock(List.class, delegatesTo(awesomeList));
* </code></pre>
*
* <p>
* This feature suffers from the same drawback as the spy.
* The mock will call the delegate if you use regular when().then() stubbing style.
* Since the real implementation is called this might have some side effects.
* Therefore you should to use the doReturn|Throw|Answer|CallRealMethod stubbing style. Example:
*
* <pre class="code"><code class="java">
* List listWithDelegate = mock(List.class, AdditionalAnswers.delegatesTo(awesomeList));
*
* //Impossible: real method is called so listWithDelegate.get(0) throws IndexOutOfBoundsException (the list is yet empty)
* when(listWithDelegate.get(0)).thenReturn("foo");
*
* //You have to use doReturn() for stubbing
* doReturn("foo").when(listWithDelegate).get(0);
* </code></pre>
*
* @param delegate The delegate to forward calls to. It does not have to be of the same type as the mock (although it usually is).
* The only requirement is that the instance should have compatible method signatures including the return values.
* Only the methods that were actually executed on the mock need to be present on the delegate type.
* @return the answer
*
* @since 1.9.5
*/
public static <T> Answer<T> delegatesTo(Object delegate) {
return (Answer<T>) new ForwardsInvocations(delegate);
}
/**
* Returns elements of the collection. Keeps returning the last element forever.
* Might be useful on occasion when you have a collection of elements to return.
* <p>
* <pre class="code"><code class="java">
* //this:
* when(mock.foo()).thenReturn(1, 2, 3);
*
* //is equivalent to:
* when(mock.foo()).thenAnswer(new ReturnsElementsOf(Arrays.asList(1, 2, 3)));
* </code></pre>
*
* @param elements The collection of elements to return.
* @return the answer
*
* @since 1.9.5
*/
public static <T> Answer<T> returnsElementsOf(Collection<?> elements) {
return (Answer<T>) new ReturnsElementsOf(elements);
}
}