Delegate.java

/*
 * Copyright (c) 2006-2011 Rogério Liesenfeld
 * This file is subject to the terms of the MIT license (see LICENSE.txt).
 */
package mockit;

/**
 * An empty interface to be used with the {@link Expectations#result} field, in order to allow test
 * code to define invocation results (return values or thrown errors/exceptions) based on 
 * test-specific logic.
 * <p/>
 * An implementation of this interface should define a method matching the signature of the recorded
 * method/constructor call.
 * That is, they should have the same name and parameters. In the case of delegating a constructor,
 * a delegate <em>method</em> should still be used, with name "$init".
 * <p/>
 * Alternatively, for the common case where the delegate implementation class defines a
 * <em>single</em> method, the name is allowed to be different from the recorded method.
 * The parameters should still match, though. Besides giving more flexibility, this ability also
 * prevents the test from breaking in case the recorded method is renamed.
 * Note that if the delegate class defines two or more methods ({@code private} ones included, if
 * any), then exactly one of them <em>must</em> match both the name and the parameters of the
 * recorded method.
 * <p/>
 * At replay time, when that method/constructor is called the corresponding "delegate" method will
 * be called to produce the desired result. The arguments passed to the delegate method will be the
 * same as those received by the recorded invocation during replay. The result can be any return
 * value compatible with the recorded method's return type, or a thrown error/exception.
 * <p/>
 * Even {@code static} methods in the mocked type can have delegates, which in turn can be static or
 * not. The same is true for {@code private}, {@code final}, and {@code native} methods.
 * <p/>
 * <a href="http://jmockit.googlecode.com/svn/trunk/www/tutorial/BehaviorBasedTesting.html#delegates">In the Tutorial</a>
 * <p/>
 * Sample tests:
 * <a href="http://code.google.com/p/jmockit/source/browse/trunk/samples/easymock/test/org/easymock/samples/DocumentManager_JMockit_Test.java">DocumentManager_JMockit_Test</a>
 */
public interface Delegate
{
}