/*
* JetS3t : Java S3 Toolkit
* Project hosted at http://bitbucket.org/jmurty/jets3t/
*
* Copyright 2006-2010 James Murty
*
* 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.jets3t.service.utils;
import java.text.DecimalFormat;
import java.text.ParseException;
import javax.swing.text.NumberFormatter;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* Formats numeric byte values into human-readable strings.
*
* @author James Murty
*/
public class ByteFormatter {
private static final Log log = LogFactory.getLog(ByteFormatter.class);
private String gigabyteSuffix = null;
private String megabyteSuffix = null;
private String kilobyteSuffix = null;
private String byteSuffix = null;
private NumberFormatter nf = null;
/**
* Constructs a formatter that will use default text to represent byte amounts.
* Default values used:
* <ul>
* <li>Gigabyte suffix: " GB"</li>
* <li>Megabyte suffix: " MB"</li>
* <li>Kilobyte suffix: " KB"</li>
* <li>Byte suffix: " B"</li>
* <li>Precision: 2 decimal places</li>
* </ul>
*
*/
public ByteFormatter() {
this(" GB", " MB", " KB", " B", 2);
}
/**
* Constructs a formatter that will use the given values when formatting byte values.
*
* @param gigabyteSuffix
* string to display at the end of gigabyte values.
* @param megabyteSuffix
* string to display at the end of megabyte values.
* @param kilobyteSuffix
* string to display at the end of kilobyte values.
* @param byteSuffix
* string to display at the end of byte values.
* @param decimalPlaces
* the number of decimal places to use when converting byte amounts into kilo, mega or giga
* byte values.
*/
public ByteFormatter(String gigabyteSuffix, String megabyteSuffix, String kilobyteSuffix,
String byteSuffix, int decimalPlaces)
{
this.gigabyteSuffix = gigabyteSuffix;
this.megabyteSuffix = megabyteSuffix;
this.kilobyteSuffix = kilobyteSuffix;
this.byteSuffix = byteSuffix;
StringBuilder numberFormatString = new StringBuilder();
numberFormatString.append("0").append((decimalPlaces > 0? "." : ""));
for (int i = 0; i < decimalPlaces; i++) {
numberFormatString.append("0");
}
nf = new NumberFormatter(new DecimalFormat(numberFormatString.toString()));
}
/**
* Converts a byte size into a human-readable string, such as "1.43 MB" or "27 KB".
* The values used are based on powers of 1024, ie 1 KB = 1024 bytes, not 1000 bytes.
*
* @param byteSize
* the byte size of some item
* @return
* a human-readable description of the byte size
*/
public String formatByteSize(long byteSize) {
String result = null;
try {
if (byteSize > Math.pow(1024,3)) {
// Report gigabytes
result = nf.valueToString(new Double(byteSize / Math.pow(1024,3))) + gigabyteSuffix;
} else if (byteSize > Math.pow(1024,2)) {
// Report megabytes
result = nf.valueToString(new Double(byteSize / Math.pow(1024,2))) + megabyteSuffix;
} else if (byteSize > 1024) {
// Report kilobytes
result = nf.valueToString(new Double(byteSize / Math.pow(1024,1))) + kilobyteSuffix;
} else if (byteSize >= 0) {
// Report bytes
result = byteSize + byteSuffix;
}
} catch (ParseException e) {
if (log.isErrorEnabled()) {
log.error("Unable to format byte size " + byteSize, e);
}
return byteSize + byteSuffix;
}
return result;
}
}