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https://issues.apache.org/jira/browse/LANG-604?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12846475#action_12846475
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Henri Yandell commented on LANG-604:
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I'm not sure I buy that most of the strings checked are untrimmed.
I'd expect most to be either a) blank or b) normal user input. If the first
character is whitespace; then I could believe that it's untrimmed.
So:
+ public static boolean isBlank(CharSequence cs) {
+ int strLen;
+ if (cs == null || (strLen = cs.length()) == 0) {
+ return true;
+ }
+ // Optimized - check first character
+ if (!Character.isWhitespace(cs.charAt(0))) {
+ return false;
+ }
+ // Optimized - starts in the middle and works out with the assumption
that
+ // most input starting with whitespace are untrimmed strings
+ for (int m = 1 + strLen / 2, i = 1; m < strLen; m++, i++) {
+ if (!Character.isWhitespace(cs.charAt(m)) ||
!Character.isWhitespace(cs.charAt(i))) {
+ return false;
+ }
+ }
+ return true;
+ }
Any thoughts?
> Optimize isBlank() for untrimmed strings
> ----------------------------------------
>
> Key: LANG-604
> URL: https://issues.apache.org/jira/browse/LANG-604
> Project: Commons Lang
> Issue Type: Improvement
> Components: lang.*
> Affects Versions: 3.0
> Reporter: Kai Gülzau
> Priority: Minor
>
> Change isBlank() to start iteration in the middle of the String.
> So you get better performance for untrimmed Strings like " dummy ".
> Here is my proposal:
> public static boolean isBlank(CharSequence cs) {
> int strLen;
> if (cs == null || (strLen = cs.length()) == 0) {
> return true;
> }
> int mid = strLen / 2, i = mid;
> for (; i < strLen; i++) {
> if (!Character.isWhitespace(cs.charAt(i))) {
> return false;
> }
> }
> for (i = 0; i < mid; i++) {
> if (!Character.isWhitespace(cs.charAt(i))) {
> return false;
> }
> }
> return true;
> }
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