org.databene.commons.RoundedNumberFormat Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of databene-commons Show documentation
Show all versions of databene-commons Show documentation
'databene commons' is an open source Java library by Volker Bergmann.
It provides extensions to the Java core library by utility classes, abstract concepts
and concrete implementations.
/*
* Copyright (C) 2004-2015 Volker Bergmann ([email protected]).
* All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.databene.commons;
import java.text.*;
import java.util.Locale;
/**
* Rounds large numbers to the four most significant digits.
* Created: 01.09.2007 16:19:14
*/
public class RoundedNumberFormat extends Format {
private static final long serialVersionUID = 6188839664275513505L;
@Override
public StringBuffer format(Object obj, StringBuffer toAppendTo, FieldPosition pos) {
return toAppendTo.append(format((Number)obj, 2));
}
@Override
public Object parseObject(String source, ParsePosition pos) {
throw new UnsupportedOperationException("Not supported");
}
public static String format(Number number, int fractionDigits) {
NumberFormat nf = DecimalFormat.getInstance(Locale.US);
//nf.setMinimumFractionDigits(fractionDigits);
nf.setMaximumFractionDigits(fractionDigits);
StringBuffer buffer = nf.format(number, new StringBuffer(), new FieldPosition(0));
int nonNullDigits = 0;
for (int i = 0; i < buffer.length(); i++) {
char c = buffer.charAt(i);
if (Character.isDigit(c)) {
if (nonNullDigits >= 2)
buffer.setCharAt(i, '0');
nonNullDigits++;
}
}
return buffer.toString();
}
}