/*
* Copyright 2008 Niclas Hedhman.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
* implied.
*
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.qi4j.library.observations;
import org.qi4j.api.common.Optional;
import org.qi4j.api.composite.Composite;
import org.qi4j.api.injection.scope.Service;
import org.qi4j.api.injection.scope.This;
import org.qi4j.library.exception.ExceptionHandling;
import java.util.ArrayList;
class MulticastObserver<T extends Observation>
implements Observer<T>, Observable<T>
{
@Optional @Service private ExceptionHandling exceptionHandling;
@This private Composite meAsComposite;
private ArrayList<Observer<T>> observers;
public MulticastObserver( Observer<T> existing )
{
observers = new ArrayList<Observer<T>>();
observers.add( existing );
}
public void notify( T observation )
{
for( Observer<T> observer : observers )
{
try
{
observer.notify( observation );
}
catch( Exception e )
{
handleException( e, observer );
}
}
}
private void handleException( Exception exception, Observer<T> observer )
{
if( exceptionHandling != null )
{
exceptionHandling.exceptionOccurred( "Exception in observer: " + observer, meAsComposite, exception );
}
else
{
}
}
public void addObserver( Observer<T> observer )
{
synchronized( this )
{
ArrayList<Observer<T>> clone = new ArrayList<Observer<T>>();
clone.addAll( observers );
clone.add( observer );
observers = clone;
}
}
public void removeObserver( Observer<T> observer )
{
synchronized( this )
{
ArrayList<Observer<T>> clone = new ArrayList<Observer<T>>();
clone.addAll( observers );
clone.remove( observer );
observers = clone;
}
}
boolean isOnlyOneLeft()
{
return observers.size() == 1;
}
Observer<T> getFirstOne()
{
return observers.get( 0 );
}
}