/*************************************************************************
* Copyright 2009-2012 Eucalyptus Systems, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 3 of the License.
*
* 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see http://www.gnu.org/licenses/.
*
* Please contact Eucalyptus Systems, Inc., 6755 Hollister Ave., Goleta
* CA 93117, USA or visit http://www.eucalyptus.com/licenses/ if you need
* additional information or have any questions.
*
* This file may incorporate work covered under the following copyright
* and permission notice:
*
* Software License Agreement (BSD License)
*
* Copyright (c) 2008, Regents of the University of California
* All rights reserved.
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* WHICH IN THE REGENTS' DISCRETION MAY INCLUDE, WITHOUT LIMITATION,
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************************************************************************/
package com.eucalyptus.util.fsm;
import java.util.Map.Entry;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.log4j.Logger;
import com.eucalyptus.records.EventRecord;
import com.eucalyptus.records.EventType;
import com.eucalyptus.records.Logs;
import com.eucalyptus.util.HasName;
import com.eucalyptus.util.Callback.Completion;
import com.eucalyptus.util.fsm.TransitionListener.Phases;
import com.google.common.base.Predicate;
import com.google.common.collect.Maps;
public class TransitionImpl<P extends HasName<P>, S extends Automata.State, T extends Automata.Transition> implements TransitionAction<P>, TransitionHandler<P, S, T>, TransitionRule<S, T> {
private static Logger LOG = Logger.getLogger( TransitionImpl.class );
private final AtomicInteger index = new AtomicInteger( 0 );
private final TransitionRule<S, T> rule;
private final ConcurrentMap<Integer, TransitionListener<P>> listeners = Maps.newConcurrentMap( );
private final TransitionAction<P> action;
TransitionImpl( final TransitionRule<S, T> transitionRule, final TransitionAction<P> action, TransitionListener<P>... listeners ) {
this.rule = transitionRule;
this.action = action;
for ( TransitionListener<P> listener : listeners ) {
this.addListener( listener );
}
}
/**
* Add a transition listener. The stages of the transition will execute for
* each listener in the order it was added:
* <ol>
* <li>{@link TransitionListener#before()}</li>
* <li>{@link TransitionListener#leave()}</li>
* <li>{@link TransitionListener#enter()}</li>
* <li>{@link TransitionListener#after()}</li>
* </ol>
*
* @param transitionListener
*/
@Override
public TransitionHandler<P, S, T> addListener( TransitionListener<P> listener ) {
Logs.extreme( ).debug( EventRecord.here( TransitionImpl.class, EventType.TRANSITION, this.toString( ), "addListener", listener.getClass( ).getSimpleName( ) ) );
this.listeners.put( index.incrementAndGet( ), listener );
return this;
}
private void removeListener( Integer key ) {
TransitionListener<P> listener = this.listeners.remove( key );
Logs.extreme( ).debug( EventRecord.here( TransitionImpl.class, EventType.TRANSITION, this.toString( ), "removeListener", listener.getClass( ).getSimpleName( ) ) );
}
/**
* @see com.eucalyptus.util.fsm.TransitionRule#getName()
*/
@Override
public T getName( ) {
return this.rule.getName( );
}
/**
* @see com.eucalyptus.util.fsm.TransitionRule#getFromStateMark()
*/
public Boolean getFromStateMark( ) {
return this.rule.getFromStateMark( );
}
/**
* @see com.eucalyptus.util.fsm.TransitionRule#getFromState()
*/
public S getFromState( ) {
return this.rule.getFromState( );
}
/**
* @see com.eucalyptus.util.fsm.TransitionRule#getToStateMark()
*/
public Boolean getToStateMark( ) {
return this.rule.getToStateMark( );
}
/**
* @see com.eucalyptus.util.fsm.TransitionRule#getToState()
*/
public S getToState( ) {
return this.rule.getToState( );
}
/**
* @return
* @see com.eucalyptus.util.fsm.TransitionRule#getErrorState()
*/
public S getErrorState( ) {
return this.rule.getErrorState( );
}
/**
* @return
* @see com.eucalyptus.util.fsm.TransitionRule#getErrorStateMark()
*/
public Boolean getErrorStateMark( ) {
return this.rule.getErrorStateMark( );
}
private boolean fireListeners( final TransitionListener.Phases phase, final Predicate<TransitionListener<P>> pred, P parent ) {
for ( Entry<Integer, TransitionListener<P>> entry : this.listeners.entrySet( ) ) {
final TransitionListener<P> tl = entry.getValue( );
Logs.extreme( ).trace( EventRecord.here( TransitionImpl.class, EventType.TRANSITION_LISTENER, "" + parent.getName( ), this.toString( ),
phase.toString( ),//
entry.getKey( ).toString( ), tl.getClass( ).toString( ) ) );
try {
if ( !pred.apply( entry.getValue( ) ) ) {
throw new TransitionListenerException( entry.getValue( ).getClass( ).getSimpleName( ) + "." + phase + "( ) returned false." );
}
} catch ( Exception t ) {
Logs.extreme( ).error( t, t );
return false;
}
}
return true;
}
/**
* @see com.eucalyptus.util.fsm.TransitionListener#before()
*/
public boolean before( final P parent ) {
if ( this.action == null ) {
throw new IllegalStateException( "Attempt to apply delegated transition before it is defined." );
} else {
this.fireListeners( Phases.before, new Predicate<TransitionListener<P>>( ) {
@Override
public boolean apply( TransitionListener<P> listener ) {
return listener.before( parent );
}
}, parent );
try {
return this.action.before( parent );
} catch ( Exception ex ) {
LOG.error( ex, ex );
return false;
}
}
}
/**
* @see com.eucalyptus.util.fsm.TransitionListener#leave()
*/
@Override
public void leave( final P parent, final Completion transitionCallback ) {
if ( this.action == null ) {
throw new IllegalStateException( "Attempt to apply delegated transition before it is defined." );
} else {
try {
this.action.leave( parent, transitionCallback );
this.fireListeners( Phases.leave, new Predicate<TransitionListener<P>>( ) {
@Override
public boolean apply( TransitionListener<P> listener ) {
listener.leave( parent );
return true;
}
}, parent );
} catch ( Exception ex ) {
Logs.extreme( ).error( ex , ex );
transitionCallback.fireException( new TransitionException( ex ) );
}
}
}
/**
* @see com.eucalyptus.util.fsm.TransitionListener#enter()
*/
public void enter( final P parent ) {
if ( this.action == null ) {
throw new IllegalStateException( "Attempt to apply delegated transition before it is defined." );
} else {
this.fireListeners( Phases.enter, new Predicate<TransitionListener<P>>( ) {
@Override
public boolean apply( TransitionListener<P> listener ) {
listener.enter( parent );
return true;
}
}, parent );
this.action.enter( parent );
}
}
/**
* @see com.eucalyptus.util.fsm.TransitionListener#after()
*/
public void after( final P parent ) {
if ( this.action == null ) {
throw new IllegalStateException( "Attempt to apply delegated transition before it is defined." );
} else {
this.fireListeners( Phases.after, new Predicate<TransitionListener<P>>( ) {
@Override
public boolean apply( TransitionListener<P> listener ) {
listener.after( parent );
return true;
}
}, parent );
this.action.after( parent );
}
}
@Override
public String toString( ) {
String actionName = "null";
if( this.action != null ) {
actionName = this.action.getClass( ).getName( ).replaceAll( "^(\\w.)*", "" );
}
// Iterable<String> listenerNames = Iterables.transform( this.listeners.values( ), new Function<TransitionListener<P>, String>( ) {
// public String apply( TransitionListener<P> arg0 ) {
// return arg0.getClass( ).getName( ).replaceAll( "^(\\w.)*", "" );
// }
// } );
return String.format( "Transition name=%s from=%s/%s to=%s/%s error=%s action=%s", this.getName( ), this.getFromState( ), this.getFromStateMark( ),
this.getToState( ), this.getToStateMark( ), this.getErrorState( ), "" + this.action );
}
/**
* @return the rule
*/
@Override
public TransitionRule<S, T> getRule( ) {
return this.rule;
}
/**
* @see java.lang.Object#hashCode()
*/
@Override
public int hashCode( ) {
final int prime = 31;
int result = 1;
result = prime * result + ( ( this.rule == null )
? 0
: this.rule.hashCode( ) );
return result;
}
/**
* @see java.lang.Object#equals(java.lang.Object)
*/
@Override
public boolean equals( Object obj ) {
if ( this == obj ) return true;
if ( obj == null ) return false;
if ( getClass( ) != obj.getClass( ) ) return false;
TransitionImpl other = ( TransitionImpl ) obj;
return this.rule.equals( other.rule );
}
/**
* @return the action
*/
@Override
public TransitionAction<P> getAction( ) {
return this.action;
}
/**
* @see java.lang.Comparable#compareTo(java.lang.Object)
*/
@Override
public int compareTo( TransitionRule<S, T> that ) {
return this.getName( ).compareTo( that.getName( ) );
}
}