StateListener.java

// Copyright 2012 Citrix Systems, Inc. Licensed under the
// Apache License, Version 2.0 (the "License"); you may not use this
// file except in compliance with the License.  Citrix Systems, Inc.
// reserves all rights not expressly granted by 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.
// 
// Automatically generated by addcopyright.py at 04/03/2012
package com.cloud.utils.fsm;

public interface StateListener <S,E,V> {
	/**
	 * Event is triggered before state machine transition finished. 
     * If you want to get the state of vm before state machine changed, you need to listen on this event
	 * @param oldState VM's old state
	 * @param event that triggered this VM state change
	 * @param newState VM's new state
	 * @param vo the VM instance
	 * @param opaque host id
	 * @param vmDao VM dao
	 * @return
	 */
	public boolean preStateTransitionEvent(S oldState, E event, S newState, V vo, boolean status, Object opaque);
	
	/**
	 * Event is triggered after state machine transition finished
	 * @param oldState VM's old state
     * @param event that triggered this VM state change
     * @param newState VM's new state
     * @param vo the VM instance
     * @param status the state transition is allowed or not
	 * @return
	 */
	public boolean postStateTransitionEvent(S oldState, E event, S newState, V vo, boolean status, Object opaque);
}