package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.impl;

import java.util.concurrent.atomic.AtomicReference;

import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.Command;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.Constants;

import fj.data.List;

public class TreeRepository
{
	private final AtomicReference<ChangeSetImpl> changeSet;
	
	public TreeRepository()
	{
		List<Command> emptyCommands = List.nil();
		
		changeSet = new AtomicReference<ChangeSetImpl>(
				new ChangeSetImpl(TreeImpl.EMPTY,emptyCommands,
						Constants.DEFAULT_OWNER,Constants.DEFAULT_REVISION_START_NUMBER,null)
			);
	}
	
	public ChangeSetImpl getCurrentChangeSet()
	{
		return changeSet.get();
	}
	
	public boolean commitChangeSet(ChangeSetImpl _newChangeSet,ChangeSetImpl _currentChangeSet)
	{
		return changeSet.compareAndSet(_currentChangeSet,_newChangeSet);
	}
}