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

import java.nio.ByteBuffer;

import fj.Ord;
import fj.data.Option;
import fj.data.TreeMap;

import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.core.Attributes;

public class AttributesImpl implements Attributes
{
	private final TreeMap<String,ByteBuffer> attrs;
	private static final TreeMap<String,ByteBuffer> EMPTY = TreeMap.empty(Ord.stringOrd);
	
	public AttributesImpl()
	{
		this(EMPTY);
	}
	
	private AttributesImpl(TreeMap<String,ByteBuffer> _attrs)
	{
		attrs = _attrs;
	}
	
	public AttributesImpl remove(String _key)
	{
		return new AttributesImpl(attrs.delete(_key));
	}
	
	public AttributesImpl put(String _key,ByteBuffer _value)
	{
		return new AttributesImpl(attrs.set(_key,_value));
	}

	@Override
	public ByteBuffer get(String _key)
	{
		Option<ByteBuffer> result = attrs.get(_key);
		return result.isSome() ? result.some() : null;
	}
}