/*************************************************************************
* 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.
*
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* 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
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************************************************************************/
package com.eucalyptus.util.fsm;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.Callable;
import org.apache.log4j.Logger;
import com.eucalyptus.records.Logs;
import com.eucalyptus.util.Exceptions;
import com.eucalyptus.util.HasFullName;
import com.eucalyptus.util.async.CheckedListenableFuture;
import com.eucalyptus.util.async.Futures;
import com.google.common.base.Joiner;
import com.google.common.collect.Lists;
import static com.eucalyptus.util.Parameters.checkParam;
import static org.hamcrest.Matchers.emptyArray;
import static org.hamcrest.Matchers.not;
public class Automata {
public interface EnumMappable {
Mapper asEnum = new Mapper( );
class Mapper {
public static <E> E[] getEnumConstants( final E input ) {
if ( Enum.class.isAssignableFrom( input.getClass( ) ) ) {
return ( E[] ) ( ( Enum ) input ).getDeclaringClass( ).getEnumConstants( );
} else {
throw new RuntimeException( "Failed to produce Enum constants because underlying class does not extend Enum: "
+ input.getClass( ) );
}
}
}
}
public interface Transition<T extends Enum<T>> extends EnumMappable, Comparable<T> {}
public interface State<S extends Enum<S>> extends EnumMappable, Comparable<S> {}
public static Logger LOG = Logger.getLogger( Automata.class );
public static <S extends Automata.State, P extends HasFullName<P>> Callable<CheckedListenableFuture<P>> sequenceTransitions( final HasStateMachine<P, S, ?> hasFsm, final S... toStates ) {
checkParam( toStates, not( emptyArray() ) );
//TODO:GRZE: enforce that the sequence of states denotes a valid transition path
S currentState = hasFsm.getStateMachine( ).getState( );
int index = Lists.newArrayList( toStates ).indexOf( currentState );
S[] actualStates = toStates;
if ( index >= 0 && index < toStates.length ) {
actualStates = Arrays.copyOfRange( toStates, index + 1, toStates.length );
}
Logs.exhaust( ).debug( "Preparing callback for " + hasFsm.getFullName( )
+ " from state "
+ currentState
+ " followed by transition sequence: "
+ Joiner.on( "->" ).join( actualStates ) );
final List<Callable<CheckedListenableFuture<P>>> callables = makeTransitionCallables( hasFsm, actualStates );
return Futures.sequence( callables.toArray( new Callable[] {} ) );
}
private static <S extends Automata.State, P extends HasFullName<P>> List<Callable<CheckedListenableFuture<P>>> makeTransitionCallables( final HasStateMachine<P, S, ?> hasFsm, final S... toStates ) {
final List<Callable<CheckedListenableFuture<P>>> callables = Lists.newArrayList( );
final StateMachine<P, S, ?> fsm = hasFsm.getStateMachine( );
if ( toStates.length > 0 ) {
for ( final S toState : toStates ) {
callables.add( new Callable<CheckedListenableFuture<P>>( ) {
@Override
public String toString( ) {
return Automata.class.getSimpleName( ) + ":"
+ hasFsm.getFullName( )
+ ":"
+ fsm.getState( )
+ "->"
+ toState;
}
@Override
public CheckedListenableFuture<P> call( ) {
S fromState = fsm.getState( );
try {
CheckedListenableFuture<P> res = fsm.transition( toState );
try {
res.get( );
Logs.extreme( ).debug( fsm.toString( ) + " transitioned from "
+ fromState
+ "->"
+ toState );
return res;
} catch ( Exception ex ) {
return res;
}
} catch ( final Exception ex ) {
Logs.extreme( ).debug( fsm.toString( ) + " failed transitioned from "
+ fromState
+ "->"
+ toState );
Exceptions.maybeInterrupted( ex );
Logs.extreme( ).error( ex, ex );
return Futures.predestinedFailedFuture( ex );
// throw Exceptions.toUndeclared( ex );
}
}
} );
}
} else {
callables.add( new Callable<CheckedListenableFuture<P>>( ) {
@Override
public String toString( ) {
return Automata.class.getSimpleName( ) + ":"
+ hasFsm.getFullName( )
+ ":"
+ fsm.getState( );
}
@Override
public CheckedListenableFuture<P> call( ) {
CheckedListenableFuture<P> ret = Futures.predestinedFuture( hasFsm.getStateMachine( ).getParent( ) );
return ret;
}
} );
}
return callables;
}
}