| 1 | package spiffy.core.lang; |
| 2 | |
| 3 | import java.io.PrintWriter; |
| 4 | import java.io.StringWriter; |
| 5 | import java.io.Writer; |
| 6 | import java.util.HashMap; |
| 7 | import java.util.Iterator; |
| 8 | |
| 9 | /** |
| 10 | * Helper methods for string manipulations and/or string representations of various entities |
| 11 | * |
| 12 | * @author Kasper B. Graversen, (c) 2007 |
| 13 | */ |
| 14 | |
| 15 | public class StringHelper { |
| 16 | |
| 17 | /** |
| 18 | * Given a string check to see if it is in a collection of strings (using <tt>equals()</tt>) |
| 19 | * |
| 20 | * @param searchString |
| 21 | * string to search for. If <tt>null</tt> false is returned. |
| 22 | * @param searchStringList |
| 23 | * list of strings to search within |
| 24 | * @return true if string is in the search list, or false if searchString is <tt>null</tt> or not present in the |
| 25 | * list |
| 26 | * @throws IllegalArgumentException |
| 27 | * when argument SearchStringList has length > 0 |
| 28 | * @since 0.03 |
| 29 | */ |
| 30 | public static boolean in(final String searchString, final String... searchStringList) { |
| 31 | if( searchString == null ) { return false; } |
| 32 | if( searchStringList.length == 0 ) { throw new IllegalArgumentException( |
| 33 | "argument SearchStringList must have length > 0"); } |
| 34 | |
| 35 | for(final String s : searchStringList) { |
| 36 | if( s.equals(searchString) ) { return true; } |
| 37 | } |
| 38 | return false; |
| 39 | } |
| 40 | |
| 41 | /** |
| 42 | * Given a string, trim it, and if different from the string "", check to see if it is in a collection of strings |
| 43 | * (using <tt>equals()</tt>). |
| 44 | * <P> |
| 45 | * This is quite often used in web programming, where input on the server side may either be <tt>null</tt>, |
| 46 | * <tt>""</tt> or some string. |
| 47 | * <p> |
| 48 | * |
| 49 | * @param searchString |
| 50 | * string to search for |
| 51 | * @param searchStringList |
| 52 | * list of strings to search within |
| 53 | * @return true if string is in the search list, or false if searchString is <tt>null</tt> or not present in the |
| 54 | * list |
| 55 | * @throws IllegalArgumentException |
| 56 | * when argument SearchStringList has length > 0 |
| 57 | * @see #in(String, String[]) |
| 58 | * @since 0.03 |
| 59 | */ |
| 60 | public static boolean inAndNonEmpty(final String searchString, final String... searchStringList) { |
| 61 | if( searchString == null ) { return false; } |
| 62 | if( searchStringList.length == 0 ) { throw new IllegalArgumentException( |
| 63 | "argument SearchStringList must have length > 0"); } |
| 64 | final String trimmedString = searchString.trim(); |
| 65 | if( trimmedString.equals("") ) { return false; } |
| 66 | |
| 67 | for(final String s : searchStringList) { |
| 68 | if( s.equals(trimmedString) ) { return true; } |
| 69 | } |
| 70 | return false; |
| 71 | } |
| 72 | |
| 73 | /** |
| 74 | * Join 0..n strings separated by a delimiter. The delimiter is not concatenated after the last element. e.g. given |
| 75 | * an iterator with the elements <tt>", ", "a", "b", "c"</tt> |
| 76 | * <pre> |
| 77 | * join(iterator) |
| 78 | * </pre> |
| 79 | * |
| 80 | * becomes |
| 81 | * |
| 82 | * <pre> |
| 83 | * "a, b, c" |
| 84 | * </pre> |
| 85 | * |
| 86 | * @param delimiter |
| 87 | * the delimiter to insert between each string. |
| 88 | * @param iterator |
| 89 | * the iterator of elements to concatenate. |
| 90 | * @return the delimiter-concatenated string. If <tt>null</tt> is given as input strings, <tt>null</tt> is |
| 91 | * returned. |
| 92 | */ |
| 93 | public static String join(final String delimiter, final Iterator<?> iterator) { |
| 94 | if( iterator == null ) { return null; } |
| 95 | |
| 96 | final StringBuilder sb = new StringBuilder(); |
| 97 | while(iterator.hasNext()) { |
| 98 | sb.append(iterator.next().toString()); |
| 99 | sb.append(delimiter); |
| 100 | } |
| 101 | // remove last delimiter |
| 102 | final int bufLen = sb.length(); |
| 103 | if( bufLen > 0 ) { // only removed if we ever added anything |
| 104 | sb.delete(bufLen - delimiter.length(), bufLen); |
| 105 | } |
| 106 | return sb.toString(); |
| 107 | } |
| 108 | |
| 109 | /** |
| 110 | * Join 0..n strings separated by a delimiter. The delimiter is not concatenated after the last element. e.g. |
| 111 | * |
| 112 | * <pre> |
| 113 | * join(", ", "a", "b", "c") |
| 114 | * </pre> |
| 115 | * |
| 116 | * becomes |
| 117 | * |
| 118 | * <pre> |
| 119 | * "a, b, c" |
| 120 | * </pre> |
| 121 | * |
| 122 | * @param delimiter |
| 123 | * the delimiter to insert between each string. |
| 124 | * @param strings |
| 125 | * the array of strings to concatenate. |
| 126 | * @return the delimiter-concatenated string. If <tt>null</tt> is given as input strings, <tt>null</tt> is |
| 127 | * returned. |
| 128 | */ |
| 129 | public static String join(final String delimiter, final String... strings) { |
| 130 | if( strings == null ) { return null; } |
| 131 | if( strings.length == 0 ) { return ""; } |
| 132 | final StringBuilder sb = new StringBuilder(); |
| 133 | |
| 134 | // add first 1.. n-1 |
| 135 | final int len = strings.length - 1; |
| 136 | int i = 0; |
| 137 | for(; i < len; i++) { |
| 138 | sb.append(strings[i]); |
| 139 | sb.append(delimiter); |
| 140 | } |
| 141 | // add last |
| 142 | sb.append(strings[i]); |
| 143 | return sb.toString(); |
| 144 | } |
| 145 | |
| 146 | /** |
| 147 | * Remove all occurrences of all specified characters. |
| 148 | * <p> |
| 149 | * This is an easy way to e.g. remove all formatting chars such as ' ', '\t', '\n' from Strings for easy comparison |
| 150 | * of code generated String. |
| 151 | * |
| 152 | * @param baseString |
| 153 | * the string to trim |
| 154 | * @param removeChars |
| 155 | * the characters to remove |
| 156 | * @return a string with the specified characters removed. |
| 157 | */ |
| 158 | public static String removeAll(final String baseString, final Character... removeChars) { |
| 159 | final StringBuffer resultString = new StringBuffer(); |
| 160 | // cache for quick lookup |
| 161 | final HashMap<Character, Object> charMatchMap = new HashMap<Character, Object>(); |
| 162 | for(final Character c : removeChars) { |
| 163 | charMatchMap.put(c, c); |
| 164 | } |
| 165 | |
| 166 | for(int i = 0; i < baseString.length(); i++) { |
| 167 | final char c = baseString.charAt(i); |
| 168 | if( charMatchMap.containsKey(c) == false ) { |
| 169 | resultString.append(c); |
| 170 | } |
| 171 | } |
| 172 | return resultString.toString(); |
| 173 | } |
| 174 | |
| 175 | private static String repeatJoin(final String baseString, final int endSize, final boolean isLeftJoin, |
| 176 | final String... joinStrings) { |
| 177 | |
| 178 | if( baseString == null ) { throw new IllegalArgumentException("Argument baseString is null"); } |
| 179 | |
| 180 | if( joinStrings == null ) { throw new IllegalArgumentException("argument joinStrings is null"); } |
| 181 | |
| 182 | if( joinStrings.length == 0 ) { return baseString; } |
| 183 | |
| 184 | if( endSize < baseString.length() ) { throw new IllegalArgumentException( |
| 185 | "Argument endSize is less than the length of baseString"); } |
| 186 | // appending as many times possible |
| 187 | final int resultingSize = endSize - baseString.length(); |
| 188 | final StringBuilder joiningStrings = new StringBuilder(resultingSize); |
| 189 | int i = 0; |
| 190 | while(true) { |
| 191 | if( joiningStrings.length() + joinStrings[i].length() <= resultingSize ) { |
| 192 | joiningStrings.append(joinStrings[i]); |
| 193 | } else { |
| 194 | break; |
| 195 | } |
| 196 | i = (i + 1) % joinStrings.length;// round-robin the joinStrings |
| 197 | } |
| 198 | |
| 199 | // final join |
| 200 | if( isLeftJoin ) { |
| 201 | joiningStrings.append(baseString); |
| 202 | } else { |
| 203 | joiningStrings.insert(0, baseString); |
| 204 | } |
| 205 | |
| 206 | return joiningStrings.toString(); |
| 207 | } |
| 208 | |
| 209 | /** |
| 210 | * Create a string by repeatedly joining/appending one or more strings in front of the string until the resulting |
| 211 | * string is equal to or as close possible to some length. E.g. * <code> |
| 212 | * repeatLeftJoin("100", 6, "#")); |
| 213 | * </code> |
| 214 | * yields <code>"fully fill", "###100"</code> |
| 215 | * |
| 216 | * <code> |
| 217 | * repeatLeftJoin("100", 6, "##")); |
| 218 | * </pre> |
| 219 | * |
| 220 | * Yields <code> "##100",</code> |
| 221 | * |
| 222 | * @param baseString |
| 223 | * the string to join strings onto |
| 224 | * @param endSize |
| 225 | * the resulting size |
| 226 | * @param joinStrings |
| 227 | * one or more strings to join onto the basestring. If the empty list is given, the baseString is returned. |
| 228 | * @return a joined string |
| 229 | */ |
| 230 | public static String repeatLeftJoin(final String baseString, final int endSize, final String... joinStrings) { |
| 231 | return repeatJoin(baseString, endSize, true, joinStrings); |
| 232 | } |
| 233 | |
| 234 | /** |
| 235 | * Create a string by repeatedly joining/appending one or more strings at the end of the string until the resulting |
| 236 | * string is equal to or as close possible to some length. E.g. |
| 237 | * |
| 238 | * <pre> |
| 239 | * repeatLeftJoin("100", 6, "#")); |
| 240 | * </pre> |
| 241 | * |
| 242 | * Yields <code>"fully fill", "###100"</code> |
| 243 | * |
| 244 | * <pre> |
| 245 | * repeatLeftJoin("100", 6, "##")); |
| 246 | * </pre> |
| 247 | * |
| 248 | * Yields <code> "##100",</code> |
| 249 | * |
| 250 | * @param baseString |
| 251 | * the string to join strings onto |
| 252 | * @param endSize |
| 253 | * the resulting size |
| 254 | * @param joinStrings |
| 255 | * one or more strings to join onto the basestring. If the empty list is given, the baseString is |
| 256 | * returned. |
| 257 | * @return a joined string |
| 258 | */ |
| 259 | public static String repeatRightJoin(final String baseString, final int endSize, final String... joinStrings) { |
| 260 | return repeatJoin(baseString, endSize, false, joinStrings); |
| 261 | } |
| 262 | |
| 263 | /** |
| 264 | * Returns a string representation of any throwable (e.g. exceptions) |
| 265 | * |
| 266 | * @param throwable |
| 267 | * the throwable/exception to get a representation from |
| 268 | * @return a string representing the throwable |
| 269 | * @since 0.1 |
| 270 | */ |
| 271 | public static String toString(final Throwable throwable) { |
| 272 | final Writer result = new StringWriter(); |
| 273 | final PrintWriter printWriter = new PrintWriter(result); |
| 274 | throwable.printStackTrace(printWriter); |
| 275 | return result.toString(); |
| 276 | } |
| 277 | |
| 278 | } |