NumberConverter.java
/*
* Copyright (c) 2008, Harald Kuhr
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.twelvemonkeys.util.convert;
import com.twelvemonkeys.lang.BeanUtil;
import com.twelvemonkeys.lang.StringUtil;
import com.twelvemonkeys.util.LRUHashMap;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.text.*;
import java.util.Arrays;
import java.util.Locale;
import java.util.Map;
/**
* Converts strings to numbers and back.
* <p>
* <small>This class has a static cache of {@code NumberFormats}, to avoid
* creation and parsing of number formats every time one is used.</small>
* </p>
*
* @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
* @author last modified by $Author: haku $
* @version $Id: //depot/branches/personal/haraldk/twelvemonkeys/release-2/twelvemonkeys-core/src/main/java/com/twelvemonkeys/util/convert/NumberConverter.java#2 $
*/
public class NumberConverter implements PropertyConverter {
// TODO: Need to either make this non-locale aware, or document that it is...
private static final DecimalFormatSymbols SYMBOLS = new DecimalFormatSymbols(Locale.US);
private static final NumberFormat sDefaultFormat = new DecimalFormat("#0.#", SYMBOLS);
private static final Map<String, Format> sFormats = new LRUHashMap<String, Format>(50);
public NumberConverter() {
}
/**
* Converts the string to a number, using the given format for parsing.
*
* @param pString the string to convert.
* @param pType the type to convert to. PropertyConverter
* implementations may choose to ignore this parameter.
* @param pFormat the format used for parsing. PropertyConverter
* implementations may choose to ignore this parameter. Also,
* implementations that require a parser format, should provide a default
* format, and allow {@code null} as the format argument.
*
* @return the object created from the given string. May safely be typecast
* to {@code java.lang.Number} or the class of the {@code type} parameter.
*
* @see Number
* @see java.text.NumberFormat
*
* @throws ConversionException
*/
public Object toObject(final String pString, final Class pType, final String pFormat) throws ConversionException {
if (StringUtil.isEmpty(pString)) {
return null;
}
try {
if (pType.equals(BigInteger.class)) {
return new BigInteger(pString); // No format?
}
if (pType.equals(BigDecimal.class)) {
return new BigDecimal(pString); // No format?
}
NumberFormat format;
if (pFormat == null) {
// Use system default format, using default locale
format = sDefaultFormat;
}
else {
// Get format from cache
format = getNumberFormat(pFormat);
}
Number num;
synchronized (format) {
num = format.parse(pString);
}
if (pType == Integer.TYPE || pType == Integer.class) {
return num.intValue();
}
else if (pType == Long.TYPE || pType == Long.class) {
return num.longValue();
}
else if (pType == Double.TYPE || pType == Double.class) {
return num.doubleValue();
}
else if (pType == Float.TYPE || pType == Float.class) {
return num.floatValue();
}
else if (pType == Byte.TYPE || pType == Byte.class) {
return num.byteValue();
}
else if (pType == Short.TYPE || pType == Short.class) {
return num.shortValue();
}
return num;
}
catch (ParseException pe) {
throw new ConversionException(pe);
}
catch (RuntimeException rte) {
throw new ConversionException(rte);
}
}
/**
* Converts the object to a string, using the given format
*
* @param pObject the object to convert.
* @param pFormat the format used for parsing. PropertyConverter
* implementations may choose to ignore this parameter. Also,
* implementations that require a parser format, should provide a default
* format, and allow {@code null} as the format argument.
*
* @return the string representation of the object, on the correct format.
*
* @throws ConversionException if the object is not a subclass of {@link java.lang.Number}
*/
public String toString(final Object pObject, final String pFormat)
throws ConversionException {
if (pObject == null) {
return null;
}
if (!(pObject instanceof Number)) {
throw new TypeMismathException(pObject.getClass());
}
try {
// Convert to string, default way
if (StringUtil.isEmpty(pFormat)) {
return sDefaultFormat.format(pObject);
}
// Convert to string, using format
NumberFormat format = getNumberFormat(pFormat);
synchronized (format) {
return format.format(pObject);
}
}
catch (RuntimeException rte) {
throw new ConversionException(rte);
}
}
private NumberFormat getNumberFormat(String pFormat) {
return (NumberFormat) getFormat(DecimalFormat.class, pFormat, SYMBOLS);
}
protected final Format getFormat(Class pFormatterClass, Object... pFormat) {
// Try to get format from cache
synchronized (sFormats) {
String key = pFormatterClass.getName() + ":" + Arrays.toString(pFormat);
Format format = sFormats.get(key);
if (format == null) {
// If not found, create...
try {
format = (Format) BeanUtil.createInstance(pFormatterClass, pFormat);
}
catch (Exception e) {
e.printStackTrace();
return null;
}
// ...and store in cache
sFormats.put(key, format);
}
return format;
}
}
}