root
/
spring-framework
mirror of https://github.com/spring-projects/spring-framework.git
1
0
Fork 0
Code Issues Actions 6 Packages Projects Releases Wiki Activity

Document terms and units in DataSize and DataUnit 

Prior to this commit, it was not readily apparent what terms and units
such as kilobyte/KB and megabyte/MB represented numerically in DataSize
and DataUnit.

This commit clarifies that such terms and units are based on binary
prefixes for data (i.e., powers of 2 instead of powers of 10).

Closes gh-23697
This commit is contained in:
Sam Brannen 2019-09-26 16:05:12 +02:00
parent 6186239287
commit 2526553ecd
2 changed files with 47 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
spring-core/src/main/java/org/springframework/util/unit/DataSize.java
View File

@ -26,10 +26,27 @@ import org.springframework.util.StringUtils;
/**
* A data size, such as '12MB'.
*
* <p>This class models a size in terms of bytes and is immutable and thread-safe.
* <p>This class models data size in terms of bytes and is immutable and thread-safe.
*
* <p>The terms and units used in this class are based on
* <a href="https://en.wikipedia.org/wiki/Binary_prefix">binary prefixes</a>
* indicating multiplication by powers of 2. Consult the following table and
* the Javadoc for {@link DataUnit} for details.
*
* <p>
* <table border="1">
* <tr><th>Term</th><th>Data Size</th><th>Size in Bytes</th></tr>
* <tr><td>byte</td><td>1B</td><td>1</td></tr>
* <tr><td>kilobyte</td><td>1KB</td><td>1,024</td></tr>
* <tr><td>megabyte</td><td>1MB</td><td>1,048,576</td></tr>
* <tr><td>gigabyte</td><td>1GB</td><td>1,073,741,824</td></tr>
* <tr><td>terabyte</td><td>1TB</td><td>1,099,511,627,776</td></tr>
* </table>
*
* @author Stephane Nicoll
* @author Sam Brannen
* @since 5.1
* @see DataUnit
*/
public final class DataSize implements Comparable<DataSize> {
@ -146,7 +163,7 @@ public final class DataSize implements Comparable<DataSize> {
* the specified default {@link DataUnit} if no unit is specified.
* <p>
* The string starts with a number followed optionally by a unit matching one of the
* supported {@link DataUnit suffixes}.
* supported {@linkplain DataUnit suffixes}.
* <p>
* Examples:
* <pre>

39
spring-core/src/main/java/org/springframework/util/unit/DataUnit.java
View File

@ -1,5 +1,5 @@
/*
* Copyright 2002-2018 the original author or authors.
* Copyright 2002-2019 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@ -19,35 +19,52 @@ package org.springframework.util.unit;
import java.util.Objects;
/**
* A standard set of data size units.
* A standard set of {@link DataSize} units.
*
* <p>The unit prefixes used in this class are
* <a href="https://en.wikipedia.org/wiki/Binary_prefix">binary prefixes</a>
* indicating multiplication by powers of 2. The following table displays the
* enum constants defined in this class and corresponding values.
*
* <p>
* <table border="1">
* <tr><th>Constant</th><th>Data Size</th><th>Power&nbsp;of&nbsp;2</th><th>Size in Bytes</th></tr>
* <tr><td>{@link #BYTES}</td><td>1B</td><td>2^0</td><td>1</td></tr>
* <tr><td>{@link #KILOBYTES}</td><td>1KB</td><td>2^10</td><td>1,024</td></tr>
* <tr><td>{@link #MEGABYTES}</td><td>1MB</td><td>2^20</td><td>1,048,576</td></tr>
* <tr><td>{@link #GIGABYTES}</td><td>1GB</td><td>2^30</td><td>1,073,741,824</td></tr>
* <tr><td>{@link #TERABYTES}</td><td>1TB</td><td>2^40</td><td>1,099,511,627,776</td></tr>
* </table>
*
* @author Stephane Nicoll
* @author Sam Brannen
* @since 5.1
* @see DataSize
*/
public enum DataUnit {
/**
* Bytes.
* Bytes, represented by suffix {@code B}.
*/
BYTES("B", DataSize.ofBytes(1)),
/**
* Kilobytes.
* Kilobytes, represented by suffix {@code KB}.
*/
KILOBYTES("KB", DataSize.ofKilobytes(1)),
/**
* Megabytes.
* Megabytes, represented by suffix {@code MB}.
*/
MEGABYTES("MB", DataSize.ofMegabytes(1)),
/**
* Gigabytes.
* Gigabytes, represented by suffix {@code GB}.
*/
GIGABYTES("GB", DataSize.ofGigabytes(1)),
/**
* Terabytes.
* Terabytes, represented by suffix {@code TB}.
*/
TERABYTES("TB", DataSize.ofTerabytes(1));
@ -68,10 +85,10 @@ public enum DataUnit {
/**
* Return the {@link DataUnit} matching the specified {@code suffix}.
* @param suffix one of the standard suffix
* @param suffix one of the standard suffixes
* @return the {@link DataUnit} matching the specified {@code suffix}
* @throws IllegalArgumentException if the suffix does not match any
* of this enum's constants
* @throws IllegalArgumentException if the suffix does not match the suffix
* of any of this enum's constants
*/
public static DataUnit fromSuffix(String suffix) {
for (DataUnit candidate : values()) {
@ -79,7 +96,7 @@ public enum DataUnit {
return candidate;
}
}
throw new IllegalArgumentException("Unknown unit '" + suffix + "'");
throw new IllegalArgumentException("Unknown data unit suffix '" + suffix + "'");
}
}