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HADOOP-7451. Generalize StringUtils#join. Contributed by Chris Douglas. 

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1143624 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Matthew Foley 2011-07-07 01:31:58 +00:00
parent d381ff25f4
commit f9e04d7544
2 changed files with 12 additions and 10 deletions
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2
common/CHANGES.txt
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@ -239,6 +239,8 @@ Trunk (unreleased changes)
HADOOP-7429. Add another IOUtils#copyBytes method. (eli) HADOOP-7429. Add another IOUtils#copyBytes method. (eli)
HADOOP-7451. Generalize StringUtils#join. (Chris Douglas via mattf)
OPTIMIZATIONS OPTIMIZATIONS
HADOOP-7333. Performance improvement in PureJavaCrc32. (Eric Caspole HADOOP-7333. Performance improvement in PureJavaCrc32. (Eric Caspole

20
common/src/java/org/apache/hadoop/util/StringUtils.java
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@ -29,6 +29,7 @@ import java.util.ArrayList;
import java.util.Arrays; import java.util.Arrays;
import java.util.Collection; import java.util.Collection;
import java.util.Date; import java.util.Date;
import java.util.Iterator;
import java.util.List; import java.util.List;
import java.util.Locale; import java.util.Locale;
import java.util.StringTokenizer; import java.util.StringTokenizer;
@ -741,16 +742,15 @@ public class StringUtils {
* @param separator Separator to join with. * @param separator Separator to join with.
* @param strings Strings to join. * @param strings Strings to join.
*/ */
public static String join(CharSequence separator, Iterable<String> strings) { public static String join(CharSequence separator, Iterable<?> strings) {
StringBuilder sb = new StringBuilder(); Iterator<?> i = strings.iterator();
boolean first = true; if (!i.hasNext()) {
for (String s : strings) { return "";
if (first) { }
first = false; StringBuilder sb = new StringBuilder(i.next().toString());
} else { while (i.hasNext()) {
sb.append(separator); sb.append(separator);
} sb.append(i.next().toString());
sb.append(s);
} }
return sb.toString(); return sb.toString();
} }