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[LANG-1033] Add StringUtils.countMatches(CharSequence, char) 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@1616372 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Gary D. Gregory 2014-08-06 23:46:30 +00:00
parent a67075b783
commit 1384457a39
3 changed files with 42 additions and 0 deletions
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1
src/changes/changes.xml
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@ -22,6 +22,7 @@
<body>
<release version="3.4" date="tba" description="tba">
<action issue="LANG-1033" type="add" dev="ggregory">Add StringUtils.countMatches(CharSequence, char)</action>
<action issue="LANG-1027" type="update" dev="rmannibucau">org.apache.commons.lang3.SystemUtils#isJavaVersionAtLeast should return true by default</action>
<action issue="LANG-1021" type="add" dev="britter" due-to="Alexander Müller">Provide methods to retrieve all fields/methods annotated with a specific type</action>
<action issue="LANG-1026" type="update" dev="britter" due-to="Alex Yursha">Bring static method references in StringUtils to consistent style</action>

33
src/main/java/org/apache/commons/lang3/StringUtils.java
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@ -5822,6 +5822,39 @@ public class StringUtils {
return count;
}
/**
* <p>Counts how many times the char appears in the given string.</p>
*
* <p>A {@code null} or empty ("") String input returns {@code 0}.</p>
*
* <pre>
* StringUtils.countMatches(null, *) = 0
* StringUtils.countMatches("", *) = 0
* StringUtils.countMatches("abba", 0) = 0
* StringUtils.countMatches("abba", 'a') = 2
* StringUtils.countMatches("abba", 'b') = 2
* StringUtils.countMatches("abba", 'x') = 0
* </pre>
*
* @param str the CharSequence to check, may be null
* @param ch the char to count
* @return the number of occurrences, 0 if the CharSequence is {@code null}
* @since 3.4
*/
public static int countMatches(final CharSequence str, final char ch) {
if (isEmpty(str)) {
return 0;
}
int count = 0;
// We could also call str.toCharArray() for faster look ups but that would generate more garbage.
for (int i = 0; i < str.length(); i++) {
if (ch == str.charAt(i)) {
count++;
}
}
return count;
}
// Character Tests
//-----------------------------------------------------------------------
/**

8
src/test/java/org/apache/commons/lang3/StringUtilsSubstringTest.java
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@ -322,4 +322,12 @@ public class StringUtilsSubstringTest {
StringUtils.countMatches("oooooooooooo", "ooo"));
}
@Test
public void testCountMatches_char() {
assertEquals(0, StringUtils.countMatches(null, 'D'));
assertEquals(5, StringUtils.countMatches("one long someone sentence of one", ' '));
assertEquals(6, StringUtils.countMatches("one long someone sentence of one", 'o'));
assertEquals(4, StringUtils.countMatches("oooooooooooo", "ooo"));
}
}