# ActivatorsInstance.java

    /*
     * Copyright (c) 2012, Paul Merlin.
     *
     * 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.runtime.activation;

    import java.util.Collections;
    import java.util.LinkedHashSet;
    import java.util.Set;
    import org.qi4j.api.activation.Activator;
    import org.qi4j.api.activation.PassivationException;
    import org.qi4j.functional.Iterables;

    /**
     * Instance of a Zest Activators of one Activation target. Contains ordered
     * Activators and roll the Activation on the target.
     *
     * @param <ActivateeType> Type of the activation target
     */
    public class ActivatorsInstance<ActivateeType>
        implements Activator<ActivateeType>
    {
        @SuppressWarnings( {"raw", "unchecked"} )
        public static final ActivatorsInstance EMPTY = new ActivatorsInstance( Collections.emptyList() );

        private final Iterable<Activator<ActivateeType>> activators;

        public ActivatorsInstance( Iterable<Activator<ActivateeType>> activators )
        {
            this.activators = activators;
        }

        @Override
        public void beforeActivation( ActivateeType activating )
            throws Exception
        {
            for( Activator<ActivateeType> activator : activators )
            {
                activator.beforeActivation( activating );
            }
        }

        @Override
        public void afterActivation( ActivateeType activated )
            throws Exception
        {
            for( Activator<ActivateeType> activator : activators )
            {
                activator.afterActivation( activated );
            }
        }

        @Override
        public void beforePassivation( ActivateeType passivating )
            throws Exception
        {
            Set<Exception> exceptions = new LinkedHashSet<>();
            for( Activator<ActivateeType> activator : Iterables.reverse( activators ) )
            {
                try
                {
                    activator.beforePassivation( passivating );
                }
                catch( Exception ex )
                {
                    exceptions.add( ex );
                }
            }
            if( !exceptions.isEmpty() )
            {
                throw new PassivationException( exceptions );
            }
        }

        @Override
        public void afterPassivation( ActivateeType passivated )
            throws Exception
        {
            Set<Exception> exceptions = new LinkedHashSet<>();
            for( Activator<ActivateeType> activator : Iterables.reverse( activators ) )
            {
                try
                {
                    activator.afterPassivation( passivated );
                }
                catch( Exception ex )
                {
                    exceptions.add( ex );
                }
            }
            if( !exceptions.isEmpty() )
            {
                throw new PassivationException( exceptions );
            }
        }

    }