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September 28, 2015 10:45
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| package dk.cs.aau.sw705e15.spoder.external; | |
| /* | |
| author: Fotis Lazarinis (actually I translated from C to Java) | |
| date: June 1997 | |
| address: Psilovraxou 12, Agrinio, 30100 | |
| comments: Compile it, import the Porter class into you program and create an instance. | |
| Then use the stripAffixes method of this method which takes a String as | |
| input and returns the stem of this String again as a String. | |
| */ | |
| class NewString { | |
| public String str; | |
| NewString() { | |
| str = ""; | |
| } | |
| } | |
| public class Porter { | |
| public static String stem(final String input) { | |
| Porter p = new Porter(); | |
| return p.stripAffixes(input); | |
| } | |
| @SuppressWarnings("static-access") | |
| private String Clean(String str) { | |
| int last = str.length(); | |
| Character ch = new Character(str.charAt(0)); | |
| String temp = ""; | |
| for (int i = 0; i < last; i++) { | |
| if (ch.isLetterOrDigit(str.charAt(i))) | |
| temp += str.charAt(i); | |
| } | |
| return temp; | |
| } // clean | |
| private boolean hasSuffix(String word, String suffix, NewString stem) { | |
| String tmp = ""; | |
| if (word.length() <= suffix.length()) | |
| return false; | |
| if (suffix.length() > 1) | |
| if (word.charAt(word.length() - 2) != suffix.charAt(suffix.length() - 2)) | |
| return false; | |
| stem.str = ""; | |
| for (int i = 0; i < word.length() - suffix.length(); i++) | |
| stem.str += word.charAt(i); | |
| tmp = stem.str; | |
| for (int i = 0; i < suffix.length(); i++) | |
| tmp += suffix.charAt(i); | |
| if (tmp.compareTo(word) == 0) | |
| return true; | |
| else | |
| return false; | |
| } | |
| private boolean vowel(char ch, char prev) { | |
| switch (ch) { | |
| case 'a': | |
| case 'e': | |
| case 'i': | |
| case 'o': | |
| case 'u': | |
| return true; | |
| case 'y': { | |
| switch (prev) { | |
| case 'a': | |
| case 'e': | |
| case 'i': | |
| case 'o': | |
| case 'u': | |
| return false; | |
| default: | |
| return true; | |
| } | |
| } | |
| default: | |
| return false; | |
| } | |
| } | |
| private int measure(String stem) { | |
| int i = 0, count = 0; | |
| int length = stem.length(); | |
| while (i < length) { | |
| for (; i < length; i++) { | |
| if (i > 0) { | |
| if (vowel(stem.charAt(i), stem.charAt(i - 1))) | |
| break; | |
| } else { | |
| if (vowel(stem.charAt(i), 'a')) | |
| break; | |
| } | |
| } | |
| for (i++; i < length; i++) { | |
| if (i > 0) { | |
| if (!vowel(stem.charAt(i), stem.charAt(i - 1))) | |
| break; | |
| } else { | |
| if (!vowel(stem.charAt(i), '?')) | |
| break; | |
| } | |
| } | |
| if (i < length) { | |
| count++; | |
| i++; | |
| } | |
| } // while | |
| return (count); | |
| } | |
| private boolean containsVowel(String word) { | |
| for (int i = 0; i < word.length(); i++) | |
| if (i > 0) { | |
| if (vowel(word.charAt(i), word.charAt(i - 1))) | |
| return true; | |
| } else { | |
| if (vowel(word.charAt(0), 'a')) | |
| return true; | |
| } | |
| return false; | |
| } | |
| private boolean cvc(String str) { | |
| int length = str.length(); | |
| if (length < 3) | |
| return false; | |
| if ((!vowel(str.charAt(length - 1), str.charAt(length - 2))) && (str.charAt(length - 1) != 'w') | |
| && (str.charAt(length - 1) != 'x') && (str.charAt(length - 1) != 'y') | |
| && (vowel(str.charAt(length - 2), str.charAt(length - 3)))) { | |
| if (length == 3) { | |
| if (!vowel(str.charAt(0), '?')) | |
| return true; | |
| else | |
| return false; | |
| } else { | |
| if (!vowel(str.charAt(length - 3), str.charAt(length - 4))) | |
| return true; | |
| else | |
| return false; | |
| } | |
| } | |
| return false; | |
| } | |
| private String step1(String str) { | |
| NewString stem = new NewString(); | |
| if (str.charAt(str.length() - 1) == 's') { | |
| if ((hasSuffix(str, "sses", stem)) || (hasSuffix(str, "ies", stem))) { | |
| String tmp = ""; | |
| for (int i = 0; i < str.length() - 2; i++) | |
| tmp += str.charAt(i); | |
| str = tmp; | |
| } else { | |
| if ((str.length() == 1) && (str.charAt(str.length() - 1) == 's')) { | |
| str = ""; | |
| return str; | |
| } | |
| if (str.charAt(str.length() - 2) != 's') { | |
| String tmp = ""; | |
| for (int i = 0; i < str.length() - 1; i++) | |
| tmp += str.charAt(i); | |
| str = tmp; | |
| } | |
| } | |
| } | |
| if (hasSuffix(str, "eed", stem)) { | |
| if (measure(stem.str) > 0) { | |
| String tmp = ""; | |
| for (int i = 0; i < str.length() - 1; i++) | |
| tmp += str.charAt(i); | |
| str = tmp; | |
| } | |
| } else { | |
| if ((hasSuffix(str, "ed", stem)) || (hasSuffix(str, "ing", stem))) { | |
| if (containsVowel(stem.str)) { | |
| String tmp = ""; | |
| for (int i = 0; i < stem.str.length(); i++) | |
| tmp += str.charAt(i); | |
| str = tmp; | |
| if (str.length() == 1) | |
| return str; | |
| if ((hasSuffix(str, "at", stem)) || (hasSuffix(str, "bl", stem)) || (hasSuffix(str, "iz", stem))) { | |
| str += "e"; | |
| } else { | |
| int length = str.length(); | |
| if ((str.charAt(length - 1) == str.charAt(length - 2)) && (str.charAt(length - 1) != 'l') | |
| && (str.charAt(length - 1) != 's') && (str.charAt(length - 1) != 'z')) { | |
| tmp = ""; | |
| for (int i = 0; i < str.length() - 1; i++) | |
| tmp += str.charAt(i); | |
| str = tmp; | |
| } else if (measure(str) == 1) { | |
| if (cvc(str)) | |
| str += "e"; | |
| } | |
| } | |
| } | |
| } | |
| } | |
| if (hasSuffix(str, "y", stem)) | |
| if (containsVowel(stem.str)) { | |
| String tmp = ""; | |
| for (int i = 0; i < str.length() - 1; i++) | |
| tmp += str.charAt(i); | |
| str = tmp + "i"; | |
| } | |
| return str; | |
| } | |
| private String step2(String str) { | |
| String[][] suffixes = { { "ational", "ate" }, { "tional", "tion" }, { "enci", "ence" }, { "anci", "ance" }, | |
| { "izer", "ize" }, { "iser", "ize" }, { "abli", "able" }, { "alli", "al" }, { "entli", "ent" }, | |
| { "eli", "e" }, { "ousli", "ous" }, { "ization", "ize" }, { "isation", "ize" }, { "ation", "ate" }, | |
| { "ator", "ate" }, { "alism", "al" }, { "iveness", "ive" }, { "fulness", "ful" }, { "ousness", "ous" }, | |
| { "aliti", "al" }, { "iviti", "ive" }, { "biliti", "ble" } }; | |
| NewString stem = new NewString(); | |
| for (int index = 0; index < suffixes.length; index++) { | |
| if (hasSuffix(str, suffixes[index][0], stem)) { | |
| if (measure(stem.str) > 0) { | |
| str = stem.str + suffixes[index][1]; | |
| return str; | |
| } | |
| } | |
| } | |
| return str; | |
| } | |
| private String step3(String str) { | |
| String[][] suffixes = { { "icate", "ic" }, { "ative", "" }, { "alize", "al" }, { "alise", "al" }, | |
| { "iciti", "ic" }, { "ical", "ic" }, { "ful", "" }, { "ness", "" } }; | |
| NewString stem = new NewString(); | |
| for (int index = 0; index < suffixes.length; index++) { | |
| if (hasSuffix(str, suffixes[index][0], stem)) | |
| if (measure(stem.str) > 0) { | |
| str = stem.str + suffixes[index][1]; | |
| return str; | |
| } | |
| } | |
| return str; | |
| } | |
| private String step4(String str) { | |
| String[] suffixes = { "al", "ance", "ence", "er", "ic", "able", "ible", "ant", "ement", "ment", "ent", "sion", | |
| "tion", "ou", "ism", "ate", "iti", "ous", "ive", "ize", "ise" }; | |
| NewString stem = new NewString(); | |
| for (int index = 0; index < suffixes.length; index++) { | |
| if (hasSuffix(str, suffixes[index], stem)) { | |
| if (measure(stem.str) > 1) { | |
| str = stem.str; | |
| return str; | |
| } | |
| } | |
| } | |
| return str; | |
| } | |
| private String step5(String str) { | |
| if (str.charAt(str.length() - 1) == 'e') { | |
| if (measure( | |
| str) > 1) {/* | |
| * measure(str)==measure(stem) if ends in vowel | |
| */ | |
| String tmp = ""; | |
| for (int i = 0; i < str.length() - 1; i++) | |
| tmp += str.charAt(i); | |
| str = tmp; | |
| } else if (measure(str) == 1) { | |
| String stem = ""; | |
| for (int i = 0; i < str.length() - 1; i++) | |
| stem += str.charAt(i); | |
| if (!cvc(stem)) | |
| str = stem; | |
| } | |
| } | |
| if (str.length() == 1) | |
| return str; | |
| if ((str.charAt(str.length() - 1) == 'l') && (str.charAt(str.length() - 2) == 'l') && (measure(str) > 1)) | |
| if (measure( | |
| str) > 1) {/* | |
| * measure(str)==measure(stem) if ends in vowel | |
| */ | |
| String tmp = ""; | |
| for (int i = 0; i < str.length() - 1; i++) | |
| tmp += str.charAt(i); | |
| str = tmp; | |
| } | |
| return str; | |
| } | |
| private String stripPrefixes(String str) { | |
| String[] prefixes = { "kilo", "micro", "milli", "intra", "ultra", "mega", "nano", "pico", "pseudo" }; | |
| int last = prefixes.length; | |
| for (int i = 0; i < last; i++) { | |
| if (str.startsWith(prefixes[i])) { | |
| String temp = ""; | |
| for (int j = 0; j < str.length() - prefixes[i].length(); j++) | |
| temp += str.charAt(j + prefixes[i].length()); | |
| return temp; | |
| } | |
| } | |
| return str; | |
| } | |
| private String stripSuffixes(String str) { | |
| str = step1(str); | |
| if (str.length() >= 1) | |
| str = step2(str); | |
| if (str.length() >= 1) | |
| str = step3(str); | |
| if (str.length() >= 1) | |
| str = step4(str); | |
| if (str.length() >= 1) | |
| str = step5(str); | |
| return str; | |
| } | |
| public String stripAffixes(String str) { | |
| str = str.toLowerCase(); | |
| str = Clean(str); | |
| if ((str != "") && (str.length() > 2)) { | |
| str = stripPrefixes(str); | |
| if (str != "") | |
| str = stripSuffixes(str); | |
| } | |
| return str; | |
| } // stripAffixes | |
| } // class |
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