Get/save parameters to an expected JMock method call?

import org.hamcrest.Description;
import org.hamcrest.TypeSafeMatcher;

public class HasCorrelationId extends TypeSafeMatcher<Message> {
    private final Object expectedCorrelationId;
    public HasCorrelationId(Object expectedCorrelationId) {
        this.expectedCorrelationId = expectedCorrelationId;
    }
    @Override
    public boolean matchesSafely(Message message) {
        if (expectedCorrelationId==message.getCorrelationId()) return true;
        return expectedCorrelationId==null? false: expectedCorrelationId.equals(message.getCorrelationId());

    }

    public void describeTo(Description description) {
        description.appendText("hasCorrelationId("+expectedCorrelationId+")");

    }

    public static HasCorrelationId hasCorrelationId(Object correlationId) {
    return new HasCorrelationId(correlationId);
    }
}

public class MyTest {
    private Mockery context = new Mockery();

  @Test
  public void testCorrelationId() {
    final Client client = context.mock(Client.class);
    final Message message1 = context.mock(Message.class,"message1");
    final Message message2 = context.mock(Message.class,"message2");

    context.checking(new Expectations(){{
        allowing(message1).getCorrelationId();will(returnValue(null));
        allowing(message2).getCorrelationId();will(returnValue("abc"));

        one(client).forwardMessage(with(hasCorrelationId(null)));
        one(client).forwardMessage(with(hasCorrelationId("abc")));
    }});

    client.forwardMessage(message1);
    client.forwardMessage(message2);
    }

}