/*
    * 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 static org.junit.Assert.fail;
  
  import org.junit.Before;
  import org.junit.Test;
  
  import ch.elca.el4j.util.observer.ObservableValue;
  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;
  
  /**
   * Another test case for the observer package.
   *
   * @svnLink $Revision: 3873 $;$Date: 2009-08-04 13:59:45 +0200 (Di, 04. Aug 2009) $;$Author: swismer $;$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/AnotherObserverTest.java $
   *
   * @author Adrian Moos (AMS)
   */
  public class AnotherObserverTest implements ValueObserver<Integer> {
  	
  	/** the size of this test. Must be in 1..32 */
  	static final int SIZE = 30;
  	
  	
  	/** the first value. */
  	SettableObservableValue<Integer> m_origin;
  	
  	/** the list of all values. */
  	ObservableValue<Integer>[] m_values;
  	
  	/** the last value. */
  	ObservableValue<Integer> m_last;
  	
  	/** counts the number of change notifications received. */
  	int m_notified;
  	
  	/**
  	 * {@inheritDoc}
  	 */
  	@SuppressWarnings("unchecked")
  	@Before
  	public void setUp() {
  		m_origin = new SettableObservableValue<Integer>(0);
  
  		m_values = (ObservableValue<Integer>[]) new ObservableValue[SIZE];
  		m_values[0] = m_origin;
  		for (int i = 1; i < m_values.length; i++) {
  			Sum s = new Sum();
  			s.m_i = i;
  			m_values[i] = new LiveValue(s);
  		}
  
  		m_last = m_values[m_values.length - 1];
  		
  		m_notified = 0;
  	}
  	
  	/***/
  	class Sum implements Computable<Integer> {
  		/***/
  		int m_i;
  		
  		/**
  		 * returns the sum of all values with index smaller {@code i}.
  		 * @return see above
  		 */
  		public Integer is() {
  			int result = 0;
  			for (int j = 0; j < m_i; j++) {
  				result += m_values[j].get();
  			}
  			return result;
  		}
  	}
  
  	/**
  	 * {@inheritDoc}
  	 */
  	public void changed(Integer newRef) {
  		m_notified++;
 	}
 	
 	/** tests update propagation. */
 	@Test
 	public void testUpdate() {
 		assertEquals("to do" , 0, m_notified);
 
 		m_last.subscribe(this);
 		assertEquals(0, (int) m_last.get());
 		assertEquals(1, m_notified);
 		
 		m_origin.set(1);
 		assertEquals(2, m_notified);
 		assertEquals(
 			1 << (m_values.length - 2),
 			(int) m_last.get()
 		);
 	}
 	
 	/** tests unsubscription. */
 	@Test
 	public void testUnsubscribe() {
 		m_last.subscribe(new ValueObserver<Integer>() {
 			public void changed(Integer newRef) {
 				if (m_origin.get() == 0) {
 					m_last.unsubscribe(this);
 				} else {
 					fail("Notification received after unsubscription.");
 				}
 			}
 		});
 		
 		m_origin.set(1);
 	}
 }