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Applying my patch from LANG-469 - adding a lastOrdinalIndexOf method to complement the existing ordinalIndexOf method 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@891142 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Henri Yandell 2009-12-16 07:32:30 +00:00
parent aa5d2162e5
commit 425dcadca5
2 changed files with 69 additions and 4 deletions
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59
src/java/org/apache/commons/lang3/StringUtils.java
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@ -831,6 +831,12 @@ public class StringUtils {
* StringUtils.ordinalIndexOf("aabaabaa", "", 2) = 0
* </pre>
*
* <p>Note that 'head(String str, int n)' may be implemented as: </p>
*
* <pre>
* str.substring(0, lastOrdinalIndexOf(str, "\n", n))
* </pre>
*
* @param str the String to check, may be null
* @param searchStr the String to find, may be null
* @param ordinal the n-th <code>searchStr</code> to find
@ -839,16 +845,25 @@ public class StringUtils {
* @since 2.1
*/
public static int ordinalIndexOf(String str, String searchStr, int ordinal) {
return ordinalIndexOf(str, searchStr, ordinal, false);
}
// Shared code between ordinalIndexOf(String,String,int) and lastOrdinalIndexOf(String,String,int)
private static int ordinalIndexOf(String str, String searchStr, int ordinal, boolean lastIndex) {
if (str == null || searchStr == null || ordinal <= 0) {
return INDEX_NOT_FOUND;
}
if (searchStr.length() == 0) {
return 0;
return lastIndex ? str.length() : 0;
}
int found = 0;
int index = INDEX_NOT_FOUND;
int index = lastIndex ? str.length() : INDEX_NOT_FOUND;
do {
index = str.indexOf(searchStr, index + 1);
if(lastIndex) {
index = str.lastIndexOf(searchStr, index - 1);
} else {
index = str.indexOf(searchStr, index + 1);
}
if (index < 0) {
return index;
}
@ -990,6 +1005,43 @@ public class StringUtils {
return str.lastIndexOf(searchStr);
}
/**
* <p>Finds the n-th last index within a String, handling <code>null</code>.
* This method uses {@link String#lastIndexOf(String)}.</p>
*
* <p>A <code>null</code> String will return <code>-1</code>.</p>
*
* <pre>
* StringUtils.lastOrdinalIndexOf(null, *, *) = -1
* StringUtils.lastOrdinalIndexOf(*, null, *) = -1
* StringUtils.lastOrdinalIndexOf("", "", *) = 0
* StringUtils.lastOrdinalIndexOf("aabaabaa", "a", 1) = 7
* StringUtils.lastOrdinalIndexOf("aabaabaa", "a", 2) = 6
* StringUtils.lastOrdinalIndexOf("aabaabaa", "b", 1) = 5
* StringUtils.lastOrdinalIndexOf("aabaabaa", "b", 2) = 2
* StringUtils.lastOrdinalIndexOf("aabaabaa", "ab", 1) = 4
* StringUtils.lastOrdinalIndexOf("aabaabaa", "ab", 2) = 1
* StringUtils.lastOrdinalIndexOf("aabaabaa", "", 1) = 8
* StringUtils.lastOrdinalIndexOf("aabaabaa", "", 2) = 8
* </pre>
*
* <p>Note that 'tail(String str, int n)' may be implemented as: </p>
*
* <pre>
* str.substring(lastOrdinalIndexOf(str, "\n", n) + 1)
* </pre>
*
* @param str the String to check, may be null
* @param searchStr the String to find, may be null
* @param ordinal the n-th last <code>searchStr</code> to find
* @return the n-th last index of the search String,
* <code>-1</code> (<code>INDEX_NOT_FOUND</code>) if no match or <code>null</code> string input
* @since 3.0
*/
public static int lastOrdinalIndexOf(String str, String searchStr, int ordinal) {
return ordinalIndexOf(str, searchStr, ordinal, true);
}
/**
* <p>Finds the first index within a String, handling <code>null</code>.
* This method uses {@link String#lastIndexOf(String, int)}.</p>
@ -5836,5 +5888,4 @@ public class StringUtils {
int strOffset = str.length() - suffix.length();
return str.regionMatches(ignoreCase, strOffset, suffix, 0, suffix.length());
}
}

14
src/test/org/apache/commons/lang3/StringUtilsEqualsIndexOfTest.java
View File

@ -230,6 +230,20 @@ public class StringUtilsEqualsIndexOfTest extends TestCase {
assertEquals(4, StringUtils.lastIndexOf("aabaabaa", "ab"));
}
public void testLastOrdinalIndexOf() {
assertEquals(-1, StringUtils.lastOrdinalIndexOf(null, "*", 42) );
assertEquals(-1, StringUtils.lastOrdinalIndexOf("*", null, 42) );
assertEquals(0, StringUtils.lastOrdinalIndexOf("", "", 42) );
assertEquals(7, StringUtils.lastOrdinalIndexOf("aabaabaa", "a", 1) );
assertEquals(6, StringUtils.lastOrdinalIndexOf("aabaabaa", "a", 2) );
assertEquals(5, StringUtils.lastOrdinalIndexOf("aabaabaa", "b", 1) );
assertEquals(2, StringUtils.lastOrdinalIndexOf("aabaabaa", "b", 2) );
assertEquals(4, StringUtils.lastOrdinalIndexOf("aabaabaa", "ab", 1) );
assertEquals(1, StringUtils.lastOrdinalIndexOf("aabaabaa", "ab", 2) );
assertEquals(8, StringUtils.lastOrdinalIndexOf("aabaabaa", "", 1) );
assertEquals(8, StringUtils.lastOrdinalIndexOf("aabaabaa", "", 2) );
}
public void testLastIndexOf_StringInt() {
assertEquals(-1, StringUtils.lastIndexOf(null, null, 0));
assertEquals(-1, StringUtils.lastIndexOf(null, null, -1));