/*
    * EL4J, the Extension Library for the J2EE, adds incremental enhancements to
    * the spring framework, http://el4j.sf.net
    * Copyright (C) 2006 by ELCA Informatique SA, Av. de la Harpe 22-24,
    * 1000 Lausanne, Switzerland, http://www.elca.ch
    *
    * EL4J is published under the GNU Lesser General Public License (LGPL)
    * Version 2.1. See http://www.gnu.org/licenses/
    *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
   * GNU Lesser General Public License for more details.
   *
   * For alternative licensing, please contact info@elca.ch
   */
  package ch.elca.el4j.tests.util.observer;
  
  import static org.junit.Assert.assertEquals;
  
  import org.junit.Before;
  import org.junit.Test;
  
  import ch.elca.el4j.util.observer.ValueObserver;
  import ch.elca.el4j.util.observer.impl.Computable;
  import ch.elca.el4j.util.observer.impl.LiveValue;
  import ch.elca.el4j.util.observer.impl.SettableObservableValue;
  
  /**
   * An observer test.
   *
   * @svnLink $Revision: 4010 $;$Date: 2009-12-01 10:59:54 +0100 (Di, 01. Dez 2009) $;$Author: jonasha $;$URL: https://el4j.svn.sourceforge.net/svnroot/el4j/branches/el4j_3_1/el4j/framework/modules/core/src/test/java/ch/elca/el4j/tests/util/observer/ObserverTest.java $
   *
   * @author Adrian Moos (AMS)
   */
  public class ObserverTest implements ValueObserver<Boolean> {
  	/** the inputs. */
  	SettableObservableValue<Boolean> m_a, m_b, m_c;
  	
  	/** the intermediary nodes/outputs. */
  	LiveValue<Boolean>  m_e, m_f, m_g;
  	
  	/** the computable for {@code g}. */
  	Computable<Boolean> m_comp;
  	
  	/** counts the number of change notifications received. */
  	int m_notified;
  
  	/**
  	 * {@inheritDoc}
  	 */
  	@Before
  	public void setUp() {
  		m_a = new SettableObservableValue<Boolean>(false);
  		m_b = new SettableObservableValue<Boolean>(false);
  		m_c = new SettableObservableValue<Boolean>(false);
  //		m_d = new LiveValue<Boolean>() {
  //			@Override
  //			protected Boolean is() {
  //				return m_a.get() != m_b.get();
  //			}
  //		};
  		m_e = new LiveValue<Boolean>() {
  			@Override
  			protected Boolean is() {
  				return m_b.get() != m_c.get();
  			}
  		};
  		m_f = new LiveValue<Boolean>() {
  			@Override
  			protected Boolean is() {
  				return m_a.get() ? m_g.get() : m_b.get();
  			}
  		};
  		m_comp = new Computable<Boolean>() {
  			public Boolean is() {
  				return (m_c.get() ? m_f.get() : m_e.get());
  			}
  		};
  		m_g = new LiveValue<Boolean>(m_comp);
  		m_notified = 0;
  	}
  	
  	/** tests subscription. */
  	@Test
  	public void testSubscribe() {
  		assertEquals(0, m_notified);
  		m_g.subscribe(this);
  		assertEquals(1, m_notified);
  	}
  	
  	/** tests silent subscription. */
  	@Test
  	public void testSilentSubscribe() {
  		m_g.subscribeSilently(this);
  		assertEquals(m_notified, 0);
  	}
  
  	/** tests propagation of changes. */
 	@Test
 	public void testInputChange() {
 		m_g.subscribe(this);
 		check();
 		m_a.set(true);
 		check();
 		m_b.set(true);
 		check();
 		m_a.set(false);
 		check();
 		m_b.set(false);
 		check();
 		m_c.set(true);
 		check();
 	}
 	
 	/** asserts that the state is consistent. */
 	private void check() {
 		check(m_g.get());
 	}
 	
 	/**
 	 * asserts that the state is consistent.
 	 * @param newRef {@code g}'s current value
 	 */
 	private void check(Boolean newRef) {
 		assertEquals(m_notified % 2 == 0, (boolean) newRef);
 		assertEquals(m_comp.is(), newRef);
 	}
 	
 	/**
 	 * {@inheritDoc}
 	 */
 	public void changed(Boolean newRef) {
 		m_notified++;
 		check(newRef);
 	}
 }