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1 package junit.framework;
2
3 public class ComparisonCompactor {
4
5 private static final String  ELLIPSIS= "...";
6 private static final String DELTA_END= "]";
7 private static final String DELTA_START= "[";
8
9 private int fContextLength;
10 private String fExpected;
11 private String fActual;
12 private int fPrefix;
13 private int fSuffix;
14
15 public ComparisonCompactor(int contextLength, String expected, String actual) {
16 fContextLength= contextLength;
17 fExpected= expected;
18 fActual= actual;
19 }
20
21 public String compact(String message) {
22 if (fExpected == null || fActual == null || areStringsEqual())
23 return Assert.format(message, fExpected, fActual);
24
25 findCommonPrefix();
26 findCommonSuffix();
27 String expected= compactString(fExpected);
28 String actual= compactString(fActual);
29 return Assert.format(message, expected, actual);
30 }
31
32 private String compactString(String source) {
33 String result= DELTA_START + source.substring(fPrefix, source.length() - fSuffix + 1) + DELTA_END;
34 if (fPrefix > 0)
35 result= computeCommonPrefix() + result;
36 if (fSuffix > 0)
37 result= result + computeCommonSuffix();
38 return result;
39 }
40
41 private void findCommonPrefix() {
42 fPrefix= 0;
43 int end= Math.min(fExpected.length(), fActual.length());
44 for (; fPrefix < end; fPrefix++) {
45 if (fExpected.charAt(fPrefix) != fActual.charAt(fPrefix))
46 break;
47 }
48 }
49
50 private void findCommonSuffix() {
51 int expectedSuffix= fExpected.length() - 1;
52 int actualSuffix= fActual.length() - 1;
53 for (; actualSuffix >= fPrefix && expectedSuffix >= fPrefix; actualSuffix--, expectedSuffix--) {
54 if (fExpected.charAt(expectedSuffix) != fActual.charAt(actualSuffix))
55 break;
56 }
57 fSuffix= fExpected.length() - expectedSuffix;
58 }
59
60 private String computeCommonPrefix() {
61 return (fPrefix > fContextLength ? ELLIPSIS : "") + fExpected.substring(Math.max(0, fPrefix - fContextLength), fPrefix);
62 }
63
64 private String computeCommonSuffix() {
65 int end= Math.min(fExpected.length() - fSuffix + 1 + fContextLength, fExpected.length());
66 return fExpected.substring(fExpected.length() - fSuffix + 1, end) + (fExpected.length() - fSuffix + 1 < fExpected.length() - fContextLength ? ELLIPSIS : "");
67 }
68
69 private boolean areStringsEqual() {
70 return fExpected.equals(fActual);
71 }
72 }
73 |
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