Java tutorial
/* This file is part of Cyclos (www.cyclos.org). A project of the Social Trade Organisation (www.socialtrade.org). Cyclos is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. Cyclos is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with Cyclos; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ package nl.strohalm.cyclos.utils.conversion; import java.math.BigDecimal; import java.math.BigInteger; import java.math.RoundingMode; import org.apache.commons.lang.StringUtils; /** * Converts a string to number with fixed position decimals. Example: 1234.56 -> 000123456 with precision = 9 and scale = 2 * @author luis */ public class FixedLengthNumberConverter<T extends Number> implements Converter<T> { private static final int DEFAULT_PRECISION = 15; private static final long serialVersionUID = 2163122907372592999L; private Class<T> numberType; private int precision = DEFAULT_PRECISION; private int scale; private BigDecimal divisor; public FixedLengthNumberConverter(final Class<T> numberType, final int scale) { this.numberType = numberType; this.scale = scale; divisor = BigDecimal.TEN.pow(scale); } public FixedLengthNumberConverter(final Class<T> numberType, final int precision, final int scale) { this(numberType, scale); this.precision = precision; } public int getPrecision() { return precision; } public int getScale() { return scale; } public void setPrecision(final int precision) { this.precision = precision; } public void setScale(final int scale) { this.scale = scale; } public String toString(final T object) { final BigDecimal number = CoercionHelper.coerce(BigDecimal.class, object); if (number == null) { return null; } return StringUtils.leftPad(number.unscaledValue().toString(), precision, '0'); } public T valueOf(final String string) { if (StringUtils.isEmpty(string)) { return null; } if (!StringUtils.isNumeric(string)) { throw new ConversionException("Invalid string. Expecting only numbers, but received " + string); } final BigDecimal number = new BigDecimal(new BigInteger(string)).divide(divisor, scale, RoundingMode.HALF_UP); return CoercionHelper.coerce(numberType, number); } }