/*************************************************************************
* 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.
*
* Redistribution and use of this software in source and binary forms,
* with or without modification, are permitted provided that the
* following conditions are met:
*
* Redistributions of source code must retain the above copyright
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*
* Redistributions in binary form must reproduce the above copyright
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* in the documentation and/or other materials provided with the
* distribution.
*
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* POSSIBILITY OF SUCH DAMAGE. USERS OF THIS SOFTWARE ACKNOWLEDGE
* THE POSSIBLE PRESENCE OF OTHER OPEN SOURCE LICENSED MATERIAL,
* COPYRIGHTED MATERIAL OR PATENTED MATERIAL IN THIS SOFTWARE,
* AND IF ANY SUCH MATERIAL IS DISCOVERED THE PARTY DISCOVERING
* IT MAY INFORM DR. RICH WOLSKI AT THE UNIVERSITY OF CALIFORNIA,
* SANTA BARBARA WHO WILL THEN ASCERTAIN THE MOST APPROPRIATE REMEDY,
* WHICH IN THE REGENTS' DISCRETION MAY INCLUDE, WITHOUT LIMITATION,
* REPLACEMENT OF THE CODE SO IDENTIFIED, LICENSING OF THE CODE SO
* IDENTIFIED, OR WITHDRAWAL OF THE CODE CAPABILITY TO THE EXTENT
* NEEDED TO COMPLY WITH ANY SUCH LICENSES OR RIGHTS.
************************************************************************/
package com.eucalyptus.util.fsm;
import java.util.concurrent.Callable;
import org.apache.log4j.Logger;
import com.eucalyptus.component.Component;
import com.eucalyptus.records.Logs;
import com.eucalyptus.util.Callback;
import com.eucalyptus.util.HasName;
import com.eucalyptus.util.Callback.Completion;
import com.eucalyptus.util.async.Callbacks;
import com.google.common.base.Predicate;
import com.google.common.util.concurrent.Callables;
public class Transitions {
private static Logger LOG = Logger.getLogger( Transitions.class );
private static TransitionException exceptionOnCondition( String message, Predicate p ) {
return new TransitionException( "Transition rejected because constraint check is false: " + message + " for class " + p.getClass( ) );
}
public static <P extends HasName<P>> TransitionListener<P> callbackAsListener( final Callback<P> p ) {
return new TransitionListener<P>( ) {
@Override
public boolean before( P parent ) {
return true;
}
@Override
public void leave( P parent ) {
try {
p.fire( parent );
} catch ( Exception ex ) {
LOG.error( ex );
Logs.extreme( ).error( ex, ex );
}
}
@Override
public void enter( P parent ) {}
@Override
public void after( P parent ) {}
};
}
private enum SimpleTransitions implements TransitionAction {
NOOP {
public void leave( HasName parent, Completion transitionCallback ) {
transitionCallback.fire( );
}
public String toString( ) {
return "TransitionAction.noop";
}
@Override
public boolean before( HasName parent ) {
return true;
}
@Override
public void enter( HasName parent ) {}
@Override
public void after( HasName parent ) {}
},
OUTOFBAND {
@Override
public void leave( HasName parent, Completion transitionCallback ) {}
public String toString( ) {
return "TransitionAction.OUTOFBAND";
}
@Override
public boolean before( HasName parent ) {
return true;
}
@Override
public void enter( HasName parent ) {}
@Override
public void after( HasName parent ) {}
};
}
public static <P extends HasName<P>> TransitionAction<P> noop( ) {
return SimpleTransitions.NOOP;
}
public static <P extends HasName<P>> TransitionListener<P> predicateAsBeforeListener( final Predicate<P> predicate ) {
TransitionListener<P> listener = new TransitionListener<P>( ) {
@Override
public boolean before( P parent ) {
return predicate.apply( parent );
}
@Override
public void leave( P parent ) {}
@Override
public void enter( P parent ) {}
@Override
public void after( P parent ) {}
};
return listener;
}
public static <P extends HasName<P>> TransitionAction<P> callbackAsAction( final Callback<P> callback ) {
TransitionAction<P> action = new AbstractTransitionAction<P>( ) {
@Override
public void leave( P parent, Callback.Completion transitionCallback ) {
try {
callback.fire( parent );
transitionCallback.fire( );
} catch ( RuntimeException ex ) {
LOG.error( ex );
transitionCallback.fireException( ex );
}
}
};
return action;
}
public static <P extends HasName<P>> TransitionAction<P> callableAsAction( final Callable<P> callable ) {
return callbackAsAction( Callbacks.forCallable( callable ) );
}
public static <P extends HasName<P>> TransitionAction<P> runnableAsAction( final Runnable runnable ) {
return callbackAsAction( Callbacks.forRunnable( runnable ) );
}
public static <P extends HasName<P>> TransitionAction<P> predicateAsAction( final Predicate<P> predicate ) {
TransitionAction<P> action = new AbstractTransitionAction<P>( ) {
@Override
public void leave( P parent, Callback.Completion transitionCallback ) {
try {
if ( !predicate.apply( parent ) ) {
transitionCallback.fireException( Transitions.exceptionOnCondition( "Transition condition failed for " + parent + " on condition ", predicate ) );
} else {
transitionCallback.fire( );
}
} catch ( RuntimeException ex ) {
Logs.extreme( ).error( ex, ex );
transitionCallback.fireException( ex );
}
}
};
return action;
}
}