Hadoop I/O - Hadoop: The Definitive Guide - page 137

assertThat ( "Finds 'o' from position 4 or later" , t . find ( "o" , 4 ),
is ( 4 ));
assertThat ( "No match" , t . find ( "pig" ), is (- 1 ));

Unicode

When we start using characters that are encoded with more than a single byte, the differ-
ences between Text and String become clear. Consider the Unicode characters shown
in Table 5-8 . [ 45 ]

Table 5-8. Unicode characters

Unicode code
point

U+0041 U+00DF U+6771 U+10400

Name LATIN CAPITAL

LETTER A

LATIN SMALL
LETTER SHARP S

N/A (a unified
Han ideograph)

DESERET CAPITAL
LETTER LONG I

UTF-8 code
units

41 c3 9f e6 9d b1 f0 90 90 80

Java repres-
entation

\u0041 \u00DF \u6771 \uD801\uDC00

All but the last character in the table, U+10400, can be expressed using a single Java
char . U+10400 is a supplementary character and is represented by two Java char s,
known as a surrogate pair . The tests in Example 5-5 show the differences between
String and Text when processing a string of the four characters from Table 5-8 .

Example 5-5. Tests showing the differences between the String and Text classes
public class StringTextComparisonTest {

@Test
public void string () throws UnsupportedEncodingException {

String s = "\u0041\u00DF\u6771\uD801\uDC00" ;
assertThat ( s . length (), is ( 5 ));
assertThat ( s . getBytes ( "UTF-8" ). length , is ( 10 ));

assertThat ( s . indexOf ( "\u0041" ), is ( 0 ));
assertThat ( s . indexOf ( "\u00DF" ), is ( 1 ));
assertThat ( s . indexOf ( "\u6771" ), is ( 2 ));
assertThat ( s . indexOf ( "\uD801\uDC00" ), is ( 3 ));

assertThat ( s . charAt ( 0 ), is ( '\u0041' ));
assertThat ( s . charAt ( 1 ), is ( '\u00DF' ));