package org.neodatis.odb.impl.core.query.values;

import java.math.BigDecimal;

import org.neodatis.odb.OID;
import org.neodatis.odb.core.layers.layer2.meta.AttributeValuesMap;
import org.neodatis.odb.core.query.execution.IQueryFieldAction;
import org.neodatis.odb.core.query.values.AbstractQueryFieldAction;

/**
 * An action to compute the max value of a field
 * @author osmadja
 *
 */
public class MinValueAction extends AbstractQueryFieldAction {

	private BigDecimal minValue;
	private OID oidOfMinValues;
	
	public MinValueAction(String attributeName, String alias) {
		super(attributeName,alias,false);
		this.minValue = new BigDecimal(Long.MAX_VALUE);
		this.oidOfMinValues = null;
	}


	public void execute(OID oid, AttributeValuesMap values) {
		Number n = (Number) values.get(attributeName);
		BigDecimal bd = ValuesUtil.convert(n);
		if(minValue.compareTo(bd)>0){
			oidOfMinValues  =oid;
			minValue = bd;
		}
	}


	public Object getValue() {
		return minValue;
	}


	public void end() {
		// nothing to do
	}

	public void start() {
		// Nothing to do
	}

	public OID getOidOfMinValues() {
		return oidOfMinValues;
	}
	
	public IQueryFieldAction copy() {
		return new MinValueAction(attributeName,alias);
	}	

}