package org.neo4j.kernel.impl.core;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import javax.transaction.Status;
import javax.transaction.Synchronization;
import javax.transaction.SystemException;
import javax.transaction.TransactionManager;
import org.neo4j.graphdb.event.TransactionData;
import org.neo4j.graphdb.event.TransactionEventHandler;
public class TransactionEventsSyncHook implements Synchronization
{
private final Collection<TransactionEventHandler<?>> handlers;
private final NodeManager nodeManager;
/**
* This is null at construction time, then populated in beforeCompletion and
* used in afterCompletion.
*/
private List<HandlerAndState> states;
private TransactionData transactionData;
private final TransactionManager tm;
public TransactionEventsSyncHook(
NodeManager nodeManager,
Collection<TransactionEventHandler<?>> transactionEventHandlers,
TransactionManager tm )
{
this.nodeManager = nodeManager;
this.handlers = transactionEventHandlers;
this.tm = tm;
}
public void beforeCompletion()
{
this.transactionData = nodeManager.getTransactionData();
try
{
if ( tm.getStatus() != Status.STATUS_ACTIVE )
{
return;
}
}
catch ( SystemException e )
{
e.printStackTrace();
}
states = new ArrayList<HandlerAndState>();
for ( TransactionEventHandler<?> handler : this.handlers )
{
try
{
Object state = handler.beforeCommit( transactionData );
states.add( new HandlerAndState( handler, state ) );
}
catch ( Throwable t )
{
// TODO Do something more than calling failure and
// throw exception?
try
{
tm.setRollbackOnly();
}
catch ( Exception e )
{
// TODO Correct?
e.printStackTrace();
}
// This will cause the transaction to throw a
// TransactionFailureException
throw new RuntimeException( t );
}
}
}
@SuppressWarnings("unchecked")
public void afterCompletion( int status )
{
if ( status == Status.STATUS_COMMITTED )
{
for ( HandlerAndState state : this.states )
{
state.handler.afterCommit( this.transactionData, state.state );
}
}
else if ( status == Status.STATUS_ROLLEDBACK )
{
if ( this.states == null )
{
// This means that the transaction was never successful
return;
}
for ( HandlerAndState state : this.states )
{
state.handler.afterRollback( this.transactionData, state.state );
}
}
else
{
throw new RuntimeException( "Unknown status " + status );
}
}
private class HandlerAndState
{
@SuppressWarnings("unchecked")
private final TransactionEventHandler handler;
private final Object state;
public HandlerAndState( TransactionEventHandler<?> handler, Object state )
{
this.handler = handler;
this.state = state;
}
}
}