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'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.file;
import java.text.DecimalFormat;
import org.databene.commons.BinaryScale;
/**
* Formats a number in a human-friendly manner, e.g. a file size in megabytes.
* Created: 06.03.2011 15:12:55
* @since 0.5.8
* @author Volker Bergmann
*/
public class BinaryScaleFormatter {
private BinaryScale scale;
private DecimalFormat numberFormat;
private String unit;
public BinaryScaleFormatter(BinaryScale scale, String unit) {
this.scale = scale;
this.unit = unit;
this.numberFormat = new DecimalFormat();
setGroupingUsed(true);
}
public void setGroupingUsed(boolean groupingUsed) {
this.numberFormat.setGroupingUsed(groupingUsed);
}
public String format(long number) {
if (scale != null)
return applyScale(scale, number);
else
return applyAutoScale(number);
}
private String applyScale(BinaryScale scale, long number) {
return numberFormat.format(Math.floor((number + scale.getFactor() - 1) / scale.getFactor())) + " " + scale.getDesignator() + unit;
}
private String applyAutoScale(long number) {
if (number >= 10 * BinaryScale.TERA.getFactor())
return applyScale(BinaryScale.TERA, number);
else if (number >= 10 * BinaryScale.GIGA.getFactor())
return applyScale(BinaryScale.GIGA, number);
else if (number >= 10 * BinaryScale.MEGA.getFactor())
return applyScale(BinaryScale.MEGA, number);
else if (number >= 10 * BinaryScale.KILO.getFactor())
return applyScale(BinaryScale.KILO, number);
else
return applyScale(BinaryScale.NONE, number);
}
}