# ActivationEvent.java

    /*
     * Copyright (c) 2011, Rickard Öberg.
     * Copyright (c) 2012, 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.api.activation;

    /**
     * ActivationEvents are fired during activation and passivation of instances in Zest.
     */
    public final class ActivationEvent
    {
        public enum EventType
        {
            ACTIVATING, ACTIVATED, PASSIVATING, PASSIVATED
        }

        private final long timestamp;
        private final Object source;
        private final EventType type;

        public ActivationEvent( Object source, EventType type )
        {
            this.timestamp = System.currentTimeMillis();
            this.source = source;
            this.type = type;
        }

        /**
         * @return the source of the Activation event
         */
        public Object source()
        {
            return source;
        }

        /**
         * @return the type of the Activation event
         */
        public EventType type()
        {
            return type;
        }

        /**
         * @return an informative message describing the event
         */
        public String message()
        {
            switch( type )
            {
            case ACTIVATING:
                return "Activating " + source;
            case ACTIVATED:
                return "Activated " + source;
            case PASSIVATING:
                return "Passivating " + source;
            case PASSIVATED:
                return "Passivated " + source;
            }
            return "";
        }

        /**
         * @see #message()
         */
        @Override
        public String toString()
        {
            return message();
        }
    }