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https://issues.apache.org/jira/browse/LANG-1480?focusedWorklogId=314347&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-314347
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ASF GitHub Bot logged work on LANG-1480:
----------------------------------------
Author: ASF GitHub Bot
Created on: 18/Sep/19 14:20
Start Date: 18/Sep/19 14:20
Worklog Time Spent: 10m
Work Description: verhas commented on pull request #446: LANG-1480
getAbbreviatedName refactored to create appropriate length …
URL: https://github.com/apache/commons-lang/pull/446#discussion_r325703983
##########
File path: src/main/java/org/apache/commons/lang3/ClassUtils.java
##########
@@ -433,48 +440,82 @@ public static String getAbbreviatedName(final Class<?>
cls, final int len) {
* <tr><td>"java.lang.String"</td><td> 5</td><td>"j.l.String"</td></tr>
* <tr><td>"java.lang.String"</td><td>15</td><td>"j.lang.String"</td></tr>
*
<tr><td>"java.lang.String"</td><td>30</td><td>"java.lang.String"</td></tr>
+ *
<tr><td>"org.apache.commons.lang3.ClassUtils"</td><td>18</td><td>"o.a.c.l.ClassUtils"</td></tr>
* </table>
- * @param className the className to get the abbreviated name for, may be
{@code null}
- * @param len the desired length of the abbreviated name
- * @return the abbreviated name or an empty string
- * @throws IllegalArgumentException if len <= 0
+ *
+ * @param className the className to get the abbreviated name for, may be
{@code null}
+ * @param len the desired length of the abbreviated name
+ * @return the abbreviated name or an empty string if the specified
+ * class name is {@code null} or empty string
+ * @throws IllegalArgumentException if {@code len <= 0}
* @since 3.4
*/
public static String getAbbreviatedName(final String className, final int
len) {
- if (len <= 0) {
- throw new IllegalArgumentException("len must be > 0");
- }
- if (className == null) {
- return StringUtils.EMPTY;
- }
-
- int availableSpace = len;
- final int packageLevels = StringUtils.countMatches(className, '.');
- final String[] output = new String[packageLevels + 1];
- int endIndex = className.length() - 1;
- for (int level = packageLevels; level >= 0; level--) {
- final int startIndex = className.lastIndexOf('.', endIndex);
- final String part = className.substring(startIndex + 1, endIndex + 1);
- availableSpace -= part.length();
- if (level > 0) {
- // all elements except top level require an additional char space
- availableSpace--;
+ if (len <= 0) {
+ throw new IllegalArgumentException("len must be > 0");
}
- if (level == packageLevels) {
- // ClassName is always complete
- output[level] = part;
- } else {
- if (availableSpace > 0) {
- output[level] = part;
- } else {
- // if no space is left still the first char is used
- output[level] = part.substring(0, 1);
- }
+ if (className == null) {
+ return StringUtils.EMPTY;
}
- endIndex = startIndex - 1;
- }
- return StringUtils.join(output, '.');
+ final char[] abbreviated = className.toCharArray();
+ int target = 0;
+ int source = 0;
+ while (source < abbreviated.length) {
+ // copy the next part
+ int runAheadTarget = target;
+ while (source < abbreviated.length && abbreviated[source] != '.') {
+ abbreviated[runAheadTarget++] = abbreviated[source++];
+ }
+
+ ++target;
+ if (useFull(runAheadTarget, source, abbreviated.length, len)
+ || target > runAheadTarget) {
+ target = runAheadTarget;
+ }
+
+ // copy the '.' unless it was the last part
+ if (source < abbreviated.length) {
+ abbreviated[target++] = abbreviated[source++];
+ }
+ }
+ return new String(abbreviated, 0, target);
+ }
+
+ /**
+ * <p>Decides if the part that was just copied to its destination
+ * location in the work array can be kept as it was copied or must be
+ * abbreviated. It must be kept when the part is the last one, which
+ * is the simple name of the class. In this case the {@code source}
+ * index, from where the characters are copied points one position
+ * after the last character, a.k.a. {@code source ==
+ * originalLength}</p>
+ *
+ * <p>If the part is not the last one then it can be kept
+ * unabridged if the number of the characters copied so far plus
+ * the character that are to be copied is less than or equal to the
+ * desired length.</p>
+ *
+ * @param runAheadTarget the target index (where the characters were
+ * copied to) pointing after the last character
+ * copied when the current part was copied
+ * @param source the source index (where the characters were
+ * copied from) pointing after the last
+ * character copied when the current part was
+ * copied
+ * @param originalLength the original length of the class full name,
+ * which is abbreviated
+ * @param desiredLength the desired length of the abbreviated class
+ * name
+ * @return {@code true} if it can be kept in its original length
+ * {@code false} if the current part has to be abbreviated and
+ */
+ private static boolean useFull(final int runAheadTarget,
Review comment:
Is this a strong requirement or something you can live with if I leave it as
it is?
As you can see from the length of the comment this is a complex expression
and the JavaDoc explains a lot about the algorithm used. Such an extensive
commend would degrade the readability of the caller method.
As per the performance: the JIT will inline this method, it should not be a
problem.
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Issue Time Tracking
-------------------
Worklog Id: (was: 314347)
Remaining Estimate: 20h 10m (was: 20h 20m)
Time Spent: 3h 50m (was: 3h 40m)
> ClassUtils. getAbbreviatedName(String ,int) returns too long result
> -------------------------------------------------------------------
>
> Key: LANG-1480
> URL: https://issues.apache.org/jira/browse/LANG-1480
> Project: Commons Lang
> Issue Type: Bug
> Components: lang.*
> Affects Versions: 3.9
> Environment: Environment independent.
> Reporter: Peter Verhas
> Assignee: Bruno P. Kinoshita
> Priority: Major
> Original Estimate: 24h
> Time Spent: 3h 50m
> Remaining Estimate: 20h 10m
>
> In some cases, the algorithm decides incorrectly when to which package names
> to abbreviate. For example, abbreviating
> {{org.apache.commons.lang3.ClassUtils}} to the length 18 will result
> {{o.a.c.lang3.ClassUtils}} (22 characters) instead of {{o.a.c.l.ClassUtils}}
> (18 characters as requested). The reason for this is that the algorithm
> starts from the right and goes to the left abbreviating the packages and
> starts to abbreviate the packages when it runs out of the available space.
> Instead, the algorithm should start from the left and abbreviate all packages
> that would result in a too-long string without abbreviating the package name.
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