Purpletech code import: abbreviate, difference, differenceAt
git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/lang/trunk@137258 13f79535-47bb-0310-9956-ffa450edef68
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Alex Chaffee
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@ -74,8 +74,9 @@ import org.apache.commons.lang.exception.NestableRuntimeException;
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* @author Stephen Colebourne
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* @author <a href="mailto:fredrik@westermarck.com">Fredrik Westermarck</a>
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* @author Holger Krauth
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* @author <a href="mailto:alex@purpletech.com">Alexander Day Chaffee</a>
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* @since 1.0
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* @version $Id: StringUtils.java,v 1.32 2003/01/20 22:15:13 dlr Exp $
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* @version $Id: StringUtils.java,v 1.33 2003/03/17 05:28:36 alex Exp $
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*/
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public class StringUtils {
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@ -1746,6 +1747,95 @@ public class StringUtils {
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}
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}
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// Abbreviating
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//--------------------------------------------------------------------------
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/**
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* Turn "Now is the time for all good men" into "Now is the time for..."
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* <p>
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* Specifically:
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* <p>
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* If str is less than max characters long, return it.
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* Else abbreviate it to (substring(str, 0, max-3) + "...").
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* If maxWidth is less than 3, throw an IllegalArgumentException.
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* In no case will it return a string of length greater than maxWidth.
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*
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* @param maxWidth maximum length of result string
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**/
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public static String abbreviate(String s, int maxWidth) {
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return abbreviate(s, 0, maxWidth);
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}
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/**
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* Turn "Now is the time for all good men" into "...is the time for..."
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* <p>
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* Works like abbreviate(String, int), but allows you to specify a "left edge"
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* offset. Note that this left edge is not necessarily going to be the leftmost
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* character in the result, or the first
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* character following the ellipses, but it will appear somewhere in the result.
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* In no case will it return a string of length greater than maxWidth.
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*
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* @param offset left edge of source string
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* @param maxWidth maximum length of result string
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**/
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public static String abbreviate(String s, int offset, int maxWidth) {
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if (maxWidth < 4)
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throw new IllegalArgumentException("Minimum abbreviation width is 4");
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if (s.length() <= maxWidth)
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return s;
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if (offset > s.length())
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offset = s.length();
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if ((s.length() - offset) < (maxWidth-3))
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offset = s.length() - (maxWidth-3);
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if (offset <= 4)
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return s.substring(0, maxWidth-3) + "...";
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if (maxWidth < 7)
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throw new IllegalArgumentException("Minimum abbreviation width with offset is 7");
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if ((offset + (maxWidth-3)) < s.length())
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return "..." + abbreviate(s.substring(offset), maxWidth-3);
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return "..." + s.substring(s.length() - (maxWidth-3));
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}
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// Difference
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//--------------------------------------------------------------------------
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/**
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* Compare two strings, and return the portion where they differ.
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* (More precisely, return the remainder of the second string,
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* starting from where it's different from the first.)
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* <p>
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* E.g. strdiff("i am a machine", "i am a robot") -> "robot"
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*
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* @return the portion of s2 where it differs from s1; returns the empty string ("") if they are equal
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**/
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public static String difference(String s1, String s2) {
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int at = differenceAt(s1, s2);
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if (at == -1)
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return "";
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return s2.substring(at);
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}
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/**
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* Compare two strings, and return the index at which the strings begin to differ
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* <p>
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* E.g. strdiff("i am a machine", "i am a robot") -> 7
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*
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* @return the index where s2 and s1 begin to differ; -1 if they are equal
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**/
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public static int differenceAt(String s1, String s2)
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{
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int i;
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for (i=0; i<s1.length() && i<s2.length(); ++i) {
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if (s1.charAt(i) != s2.charAt(i)) {
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break;
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}
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}
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if (i<s2.length() || i<s1.length()) {
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return i;
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}
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return -1;
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}
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// Misc
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//--------------------------------------------------------------------------
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@ -68,7 +68,7 @@ import junit.textui.TestRunner;
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* @author <a href="mailto:ridesmet@users.sourceforge.net">Ringo De Smet</a>
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* @author <a href="mailto:fredrik@westermarck.com>Fredrik Westermarck</a>
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* @author Holger Krauth
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* @version $Id: StringUtilsTest.java,v 1.13 2003/01/20 22:15:13 dlr Exp $
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* @version $Id: StringUtilsTest.java,v 1.14 2003/03/17 05:28:37 alex Exp $
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*/
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public class StringUtilsTest extends TestCase {
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@ -377,5 +377,74 @@ public class StringUtilsTest extends TestCase {
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assertEquals("containsOnly(String3, chars3) success", true, StringUtils.containsOnly(str3, chars3));
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}
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public void testAbbreviate()
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{
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assertEquals("abbreviate(String,int) failed",
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"short", StringUtils.abbreviate("short", 10));
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assertEquals("abbreviate(String,int) failed",
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"Now is ...", StringUtils.abbreviate("Now is the time for all good men to come to the aid of their party.", 10));
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String raspberry = "raspberry peach";
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assertEquals("abbreviate(String,int) failed (one past limit)",
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"raspberry p...", StringUtils.abbreviate(raspberry, 14));
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assertEquals("abbreviate(String,int) (at limit)",
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"raspberry peach", StringUtils.abbreviate("raspberry peach", 15));
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assertEquals("abbreviate(String,int) (one below limit)",
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"raspberry peach", StringUtils.abbreviate("raspberry peach", 16));
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assertEquals("abbreviate(String,int,int) failed",
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"raspberry peach", StringUtils.abbreviate(raspberry, 11, 15));
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assertAbbreviateWithOffset("abcdefg...", -1, 10);
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assertAbbreviateWithOffset("abcdefg...", 0, 10);
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assertAbbreviateWithOffset("abcdefg...", 1, 10);
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assertAbbreviateWithOffset("abcdefg...", 2, 10);
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assertAbbreviateWithOffset("abcdefg...", 3, 10);
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assertAbbreviateWithOffset("abcdefg...", 4, 10);
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assertAbbreviateWithOffset("...fghi...", 5, 10);
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assertAbbreviateWithOffset("...ghij...", 6, 10);
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assertAbbreviateWithOffset("...hijk...", 7, 10);
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assertAbbreviateWithOffset("...ijklmno", 8, 10);
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assertAbbreviateWithOffset("...ijklmno", 9, 10);
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assertAbbreviateWithOffset("...ijklmno", 10, 10);
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assertAbbreviateWithOffset("...ijklmno", 10, 10);
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assertAbbreviateWithOffset("...ijklmno", 11, 10);
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assertAbbreviateWithOffset("...ijklmno", 12, 10);
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assertAbbreviateWithOffset("...ijklmno", 13, 10);
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assertAbbreviateWithOffset("...ijklmno", 14, 10);
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assertAbbreviateWithOffset("...ijklmno", 15, 10);
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assertAbbreviateWithOffset("...ijklmno", 16, 10);
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assertAbbreviateWithOffset("...ijklmno", Integer.MAX_VALUE, 10);
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}
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private void assertAbbreviateWithOffset(String expected, int offset, int maxWidth)
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{
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String abcdefghijklmno = "abcdefghijklmno";
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String message = "abbreviate(String,int,int) failed";
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String actual = StringUtils.abbreviate(abcdefghijklmno, offset, maxWidth);
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if (offset >= 0 && offset < abcdefghijklmno.length()) {
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assertTrue(message + " -- should contain offset character",
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actual.indexOf((char)('a'+offset)) != -1);
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}
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assertTrue(message + " -- should not be greater than maxWidth",
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actual.length() <= maxWidth);
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assertEquals(message, expected, actual);
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}
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public void testDifference()
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{
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assertEquals("robot", StringUtils.difference("i am a machine", "i am a robot"));
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assertEquals("", StringUtils.difference("foo", "foo"));
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assertEquals("you are a robot", StringUtils.difference("i am a robot", "you are a robot"));
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}
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public void testDifferenceAt()
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{
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assertEquals(7, StringUtils.differenceAt("i am a machine", "i am a robot"));
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assertEquals(-1, StringUtils.differenceAt("foo", "foo"));
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assertEquals(0, StringUtils.differenceAt("i am a robot", "you are a robot"));
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}
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}
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