Epoch.java

package org.araqne.logdb.query.expr;

import java.util.Date;
import java.util.List;

import org.araqne.logdb.QueryContext;
import org.araqne.logdb.Row;

public class Epoch extends FunctionExpression {

	private Expression valueExpr;

	public Epoch(QueryContext ctx, List<Expression> exprs) {
		super("epoch", exprs, 1);

		this.valueExpr = exprs.get(0);
	}

	@Override
	public Object eval(Row map) {
		Object value = valueExpr.eval(map);
		if (value == null)
			return null;

		try {
			String s = value.toString();
			if (s.isEmpty())
				return null;

			long time = Long.valueOf(s);

			// assume time as millisecond
			// if x1000 is larger than 9999-01-01
			long ms = time * 1000;

			if (ms >= 253402300799000L)
				return new Date(time);

			return new Date(ms);
		} catch (Throwable t) {
			return null;
		}
	}
}