/*************************************************************************
* Copyright 2009-2014 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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*
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*
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* WHICH IN THE REGENTS' DISCRETION MAY INCLUDE, WITHOUT LIMITATION,
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* NEEDED TO COMPLY WITH ANY SUCH LICENSES OR RIGHTS.
************************************************************************/
package com.eucalyptus.compute.common.internal.util;
import java.util.Objects;
import javax.annotation.Nullable;
import javax.persistence.MappedSuperclass;
import com.eucalyptus.entities.Entities;
import com.eucalyptus.entities.UserMetadata;
import com.eucalyptus.util.HasNaturalId;
import com.eucalyptus.auth.principal.OwnerFullName;
@MappedSuperclass
public abstract class PersistentReference<T extends PersistentReference<T, R>, R extends HasNaturalId> extends UserMetadata<Reference.State> implements Reference<T, R> {
private static final long serialVersionUID = 1L;
protected PersistentReference( final OwnerFullName owner, final String displayName ) {
super( owner, displayName );
}
@SuppressWarnings( "unchecked" )
private T get( ) {
return ( T ) this;
}
/**
* Referer may be null!
*/
protected abstract void setReference( @Nullable R referer );
protected abstract R getReference( );
/**
* {@inheritDoc ResourceAlllocation#allocate()}
*
* @see Reference#allocate()
* @return
*/
@Override
public final T allocate( ) throws ResourceAllocationException {
return this.doSetReferer( null, Reference.State.FREE, Reference.State.PENDING );
}
/**
* {@inheritDoc ResourceAlllocation#release()}
*
* @see Reference#release()
* @return
* @throws ResourceAllocationException
*/
@Override
public T release( ) throws ResourceAllocationException {
return this.doSetReferer( null, null, Reference.State.FREE );
}
/**
* {@inheritDoc ResourceAlllocation#teardown()}
*
* @throws ResourceAllocationException
*
* @see Reference#teardown()
*/
@Override
public final boolean teardown( ) throws ResourceAllocationException {
Entities.delete( this );
return true;
}
/**
* {@inheritDoc ResourceAlllocation#reclaim()}
*/
@Override
public final T reclaim( final R referer ) throws ResourceAllocationException {
return this.doSetReferer( referer, null, State.EXTANT );
}
protected T doSetReferer( final R referer, final Reference.State preconditionState, final Reference.State finalState ) throws ResourceAllocationException {
this.checkPreconditions( referer, preconditionState, finalState );
if ( ( referer != null ) && !Reference.State.PENDING.equals( finalState ) ) {
this.setReference( referer );
this.setState( finalState );
} else {
this.setReference( null );
this.setState( finalState );
}
return get( );
}
protected void ensureTransaction( ) {
if ( ( !Entities.hasTransaction( this ) ) ) {
throw new RuntimeException( "Error allocating resource " + PersistentReference.this.getClass( ).getSimpleName( ) + " with id "
+ this.getDisplayName( ) + " as there is no ongoing transaction." );
}
}
private void checkPreconditions( R referer, final Reference.State preconditionState, Reference.State finalState ) throws RuntimeException {
ensureTransaction( );
State currentState = this.getState( );
boolean matchPrecondition = preconditionState == null || ( currentState != null && preconditionState.equals( currentState ) );
boolean matchFinal = ( finalState == null && currentState == null ) || ( finalState != null && currentState != null && finalState.equals( currentState ) );
boolean matchReferer = ( this.getReference( ) == null ) || ( referer != null && this.getReference( ) != null && referer.equals( this.getReference( ) ) );
if ( !( ( matchFinal && matchReferer ) || matchPrecondition ) ) {
throw new RuntimeException( "Error allocating resource " + PersistentReference.this.getClass( ).getSimpleName( )
+ " with id "
+ this.getDisplayName( )
+ " as the state is not either the precondition "
+ preconditionState.name( )
+ " or the final state "
+ Objects.toString( finalState )
+ " (currently "
+ Objects.toString( currentState )
+ ", referer "
+ this.getReference( )
+ ", passed referer "
+ referer
+ ")" );
}
}
@Override
public T set( final R referer ) throws ResourceAllocationException {
return this.doSetReferer( referer, State.PENDING, State.EXTANT );
}
}