DateFormatAdjuster.java
| 1 |
package fillin.date; |
|---|---|
| 2 |
|
| 3 |
/**
|
| 4 |
* A utility class that adjusts date format strings to match a specified component order, replicating OpenEdge
|
| 5 |
* ABL's format adjustment behavior as a pure function.
|
| 6 |
*/
|
| 7 |
public class DateFormatAdjuster |
| 8 |
{
|
| 9 |
/**
|
| 10 |
* Left-rotate elements in a 3-item array (e.g., [A,B,C] becomes [B,C,A]).
|
| 11 |
*
|
| 12 |
* @param a
|
| 13 |
* the array to rotate
|
| 14 |
*/
|
| 15 |
private static void rotateLeft(final String[] a) |
| 16 |
{
|
| 17 |
swap(a, 0, 2); |
| 18 |
swap(a, 0, 1); |
| 19 |
} |
| 20 |
|
| 21 |
/**
|
| 22 |
* Right-rotate elements in a 3-item array (e.g., [A,B,C] → [C,A,B]).
|
| 23 |
*
|
| 24 |
* @param a
|
| 25 |
* the array to rotate
|
| 26 |
*/
|
| 27 |
private static void rotateRight(final String[] a) |
| 28 |
{
|
| 29 |
swap(a, 1, 2); |
| 30 |
swap(a, 0, 1); |
| 31 |
} |
| 32 |
|
| 33 |
/**
|
| 34 |
* Swap two components in array
|
| 35 |
*
|
| 36 |
* @param a
|
| 37 |
* the array to modify
|
| 38 |
* @param i1
|
| 39 |
* the first valid array index to swap
|
| 40 |
* @param i2
|
| 41 |
* the second valid array index to swap
|
| 42 |
*/
|
| 43 |
private static final void swap(final String[] a, final int i1, final int i2) |
| 44 |
{
|
| 45 |
final String t = a[i1]; |
| 46 |
a[i1] = a[i2]; |
| 47 |
a[i2] = t; |
| 48 |
} |
| 49 |
|
| 50 |
/**
|
| 51 |
* Reorders components and separators in a date format string for date format assignment based on the
|
| 52 |
* specified component order.
|
| 53 |
* <p>
|
| 54 |
* This method adjusts the format string to align with the given order, but reordering occurs only when
|
| 55 |
* the year component has fewer than 4 digits and exactly one other component has exactly 4 digits. In
|
| 56 |
* such cases, the components are rearranged so the year component has 4 digits. Depending on the format
|
| 57 |
* and order, reordering may involve swapping two components or rotating all components left or right.
|
| 58 |
* </p>
|
| 59 |
* <p>
|
| 60 |
* When reordering is required, separators are adjusted based on the specified order:
|
| 61 |
* </p>
|
| 62 |
* <ul>
|
| 63 |
* <li><b>Month in first position ("mdy", "myd"):</b> Separators remain in their original order.</li>
|
| 64 |
* <li><b>Month in middle position ("dmy", "ymd"):</b> Separators are swapped.</li>
|
| 65 |
* <li><b>Month in last position ("dym", "ydm"):</b> The second separator is copied to the first position.</li>
|
| 66 |
* </ul>
|
| 67 |
*
|
| 68 |
* @param format a valid date format string (e.g., "9/99.9999", "999-99-99") containing two
|
| 69 |
* separators (dot, slash, or dash)
|
| 70 |
* @param order the desired component order ("mdy", "dmy", "ymd", "myd", "dym", "ydm"), representing
|
| 71 |
* the SESSION:DATE-FORMAT setting in OpenEdge ABL
|
| 72 |
* @param expected the expected output string for visual inspection during development; this parameter
|
| 73 |
* is temporary and must be removed in production
|
| 74 |
*
|
| 75 |
* @return the adjusted format string matching the specified order for date format assignment,
|
| 76 |
* or the original format if no reordering is required
|
| 77 |
*/
|
| 78 |
public static String reorderForDateFormatAssignment(final String format, final String order, |
| 79 |
final String expected) |
| 80 |
{
|
| 81 |
/*
|
| 82 |
* 1. Test if the component re-ordering is required
|
| 83 |
*/
|
| 84 |
final String[] comps = format.split("[./-]"); |
| 85 |
assert comps.length == 3 : "We accept only formats containing separators"; |
| 86 |
|
| 87 |
// Find a components with 4 digits
|
| 88 |
int longComponentIdx = -1; |
| 89 |
for (int i = 0; i < 3; i++) |
| 90 |
{
|
| 91 |
final String comp = comps[i]; |
| 92 |
if (comp.length() == 4) |
| 93 |
{
|
| 94 |
if (longComponentIdx >= 0) |
| 95 |
{
|
| 96 |
// There can be only one
|
| 97 |
return format;
|
| 98 |
} |
| 99 |
longComponentIdx = i; |
| 100 |
} |
| 101 |
} |
| 102 |
|
| 103 |
if (longComponentIdx == -1) |
| 104 |
{
|
| 105 |
// No long format
|
| 106 |
return format;
|
| 107 |
} |
| 108 |
|
| 109 |
final int yearIndex = order.indexOf('y'); |
| 110 |
assert yearIndex >= 0; |
| 111 |
if (yearIndex == longComponentIdx)
|
| 112 |
{
|
| 113 |
// Year is already the long one
|
| 114 |
return format;
|
| 115 |
} |
| 116 |
|
| 117 |
// Extract separators
|
| 118 |
final int leftSeparatorPos = comps[0].length(); |
| 119 |
final char leftSeparatorInitial = format.charAt(leftSeparatorPos); |
| 120 |
final int rightSeparatorPos = leftSeparatorPos + 1 + comps[1].length(); |
| 121 |
final char rightSeparatorInitial = format.charAt(rightSeparatorPos); |
| 122 |
|
| 123 |
switch (order)
|
| 124 |
{
|
| 125 |
case "mdy": |
| 126 |
if (longComponentIdx == 0) |
| 127 |
{
|
| 128 |
rotateLeft(comps); |
| 129 |
} |
| 130 |
else
|
| 131 |
{
|
| 132 |
swap(comps, 1, 2); |
| 133 |
} |
| 134 |
|
| 135 |
break;
|
| 136 |
|
| 137 |
case "dmy": |
| 138 |
if (longComponentIdx == 0) |
| 139 |
{
|
| 140 |
swap(comps, 0, 2); |
| 141 |
} |
| 142 |
else
|
| 143 |
{
|
| 144 |
rotateRight(comps); |
| 145 |
} |
| 146 |
|
| 147 |
break;
|
| 148 |
|
| 149 |
case "ymd": |
| 150 |
if (longComponentIdx == 1) |
| 151 |
{
|
| 152 |
swap(comps, 0, 1); |
| 153 |
} |
| 154 |
else
|
| 155 |
{
|
| 156 |
rotateRight(comps); |
| 157 |
} |
| 158 |
|
| 159 |
break;
|
| 160 |
|
| 161 |
case "myd": |
| 162 |
if (longComponentIdx == 0) |
| 163 |
{
|
| 164 |
swap(comps, 0, 1); |
| 165 |
} |
| 166 |
else
|
| 167 |
{
|
| 168 |
swap(comps, 1, 2); |
| 169 |
} |
| 170 |
|
| 171 |
break;
|
| 172 |
|
| 173 |
case "dym": |
| 174 |
if (longComponentIdx == 0) |
| 175 |
{
|
| 176 |
rotateRight(comps); |
| 177 |
} |
| 178 |
else
|
| 179 |
{
|
| 180 |
rotateLeft(comps); |
| 181 |
} |
| 182 |
|
| 183 |
break;
|
| 184 |
|
| 185 |
case "ydm": |
| 186 |
if (longComponentIdx == 1) |
| 187 |
{
|
| 188 |
rotateLeft(comps); |
| 189 |
} |
| 190 |
else
|
| 191 |
{
|
| 192 |
swap(comps, 0, 2); |
| 193 |
} |
| 194 |
|
| 195 |
break;
|
| 196 |
|
| 197 |
default:
|
| 198 |
throw new IllegalArgumentException("Unexpected date order"); |
| 199 |
} |
| 200 |
|
| 201 |
final char leftSeparator; |
| 202 |
final char rightSeparator; |
| 203 |
|
| 204 |
/*
|
| 205 |
* 2. Compute separators
|
| 206 |
*/
|
| 207 |
switch (order.indexOf('m')) |
| 208 |
{
|
| 209 |
case 0: |
| 210 |
{
|
| 211 |
// Separators order preserved
|
| 212 |
leftSeparator = leftSeparatorInitial; |
| 213 |
rightSeparator = rightSeparatorInitial; |
| 214 |
|
| 215 |
break;
|
| 216 |
} |
| 217 |
case 1: |
| 218 |
{
|
| 219 |
// Separators are swapped
|
| 220 |
leftSeparator = rightSeparatorInitial; |
| 221 |
rightSeparator = leftSeparatorInitial; |
| 222 |
|
| 223 |
break;
|
| 224 |
} |
| 225 |
case 2: |
| 226 |
{
|
| 227 |
// Right separator is copied to the left
|
| 228 |
leftSeparator = rightSeparator = rightSeparatorInitial; |
| 229 |
|
| 230 |
break;
|
| 231 |
} |
| 232 |
default:
|
| 233 |
throw new IllegalArgumentException("Unexpected SESSION:DATE-FORMAT value: " + order); |
| 234 |
} |
| 235 |
|
| 236 |
// Build the result
|
| 237 |
final StringBuilder result = new StringBuilder(10); |
| 238 |
|
| 239 |
result.append(comps[0]);
|
| 240 |
result.append(leftSeparator); |
| 241 |
result.append(comps[1]);
|
| 242 |
result.append(rightSeparator); |
| 243 |
result.append(comps[2]);
|
| 244 |
|
| 245 |
return result.toString();
|
| 246 |
} |
| 247 |
} |