package org.alfresco.repo.node;

import java.util.List;
import java.util.Set;

import org.alfresco.service.cmr.repository.NodeRef;

/**
 * A component that pre-fetches cached data for the given nodes.  Client code can use
 * this component when a list of <code>NodeRef</code> instances will be processed in
 * a data-intensive manner.
 * 
 * @author Andy Hind
 * @author Derek Hulley
 */
public interface NodeBulkLoader
{
    /**
     * Gets the current set of cached ancestors of the given list of nodes.
     * 
     * @param nodeIds
     *            a list of node IDs to visit
     * @return the current set of cached ancestors of the given list of nodes, including the nodes themselves.
     */
    public Set<Long> getCachedAncestors(List<Long> nodeIds);

    /**
     * Transaction-scope setting to make the Node loader to guarantee the validity of all
     * caches: some cache data will be reloaded; some cache data will be considered safe. 
     */
    public void setCheckNodeConsistency();

    /**
     * Pre-cache data relevant to the given nodes.  There is no need to split the collection
     * up before calling this method; it is up to the implementations to ensure that batching
     * is done where necessary.
     * 
     * @param nodeRefs          the nodes that will be cached.
     */
    public void cacheNodes(List<NodeRef> nodeRefs);
    
    /**
     * Pre-cache data relevant to the given nodes.  There is no need to split the collection
     * up before calling this method; it is up to the implementations to ensure that batching
     * is done where necessary.
     * 
     * @param nodeIds           the nodes that will be cached.
     */
    public void cacheNodesById(List<Long> nodeIds);
    
    /**
     * <b>FOR TESTING ONLY: </b>Clears out node cache data
     */
    public void clear();
}