addons/implied-repos/common/src/main/java/org/commonjava/indy/implrepo/change/ImpliedRepoMaintainer.java
public void updateImpliedStores( @Observes final ArtifactStorePreUpdateEvent event )
    {
        if ( !storeManager.isStarted() )
        {
            return;
        }

        if ( !config.isEnabled() )
        {
            logger.debug( "Implied-repository processing is not enabled." );
            return;
        }

        try
        {
            // TODO: Update for changes map.
            final Map<StoreKey, ArtifactStore> currentStores = mapStores( event );

            for ( final ArtifactStore store : event )
            {
                logger.debug( "Processing store: {} for implied repo metadata", store );
                processStore( store, currentStores );
            }
        }
        catch ( Throwable error )
        {
            Logger logger = LoggerFactory.getLogger( getClass() );
            logger.error( String.format( "Implied-repository maintenance failed: %s", error.getMessage() ), error );
        }
    }
public void updateImpliedStores( @Observes final ArtifactStorePreUpdateEvent event )
    {
        if ( !storeManager.isStarted() )
        {
            return;
        }

        if ( !config.isEnabled() )
        {
            logger.debug( "Implied-repository processing is not enabled." );
            return;
        }

        try
        {
            // TODO: Update for changes map.
            final Map<StoreKey, ArtifactStore> currentStores = mapStores( event );

            for ( final ArtifactStore store : event )
            {
                logger.debug( "Processing store: {} for implied repo metadata", store );
                processStore( store, currentStores );
            }
        }
        catch ( Throwable error )
        {
            Logger logger = LoggerFactory.getLogger( getClass() );
            logger.error( String.format( "Implied-repository maintenance failed: %s", error.getMessage() ), error );
        }
    }
We cannot currently remove formerly implied repos because we can't distinguish between the above states.