1 | /*
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2 | * Stemmer.java
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3 | * Copyright (C) 2001 Eibe Frank
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4 | *
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5 | * This program is free software; you can redistribute it and/or modify
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6 | * it under the terms of the GNU General Public License as published by
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7 | * the Free Software Foundation; either version 2 of the License, or
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8 | * (at your option) any later version.
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9 | *
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10 | * This program is distributed in the hope that it will be useful,
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11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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13 | * GNU General Public License for more details.
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14 | *
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15 | * You should have received a copy of the GNU General Public License
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16 | * along with this program; if not, write to the Free Software
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17 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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18 | */
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19 |
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20 | import java.util.*;
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21 | import java.io.*;
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22 |
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23 | /**
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24 | * Abstract class for stemmers.
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25 | *
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26 | * @author Eibe Frank ([email protected])
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27 | * @version 1.0
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28 | */
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29 | public abstract class Stemmer implements Serializable {
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30 |
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31 | /**
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32 | * Iterated stemming of the given word.
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33 | */
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34 | public abstract String stem(String str);
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35 |
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36 | /**
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37 | * Stems everything in the given string.
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38 | */
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39 | public String stemString(String str) {
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40 |
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41 | StringBuffer result = new StringBuffer();
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42 | int start = -1;
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43 | for (int j = 0; j < str.length(); j++) {
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44 | char c = str.charAt(j);
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45 | if (Character.isLetterOrDigit(c)) {
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46 | if (start == -1) {
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47 | start = j;
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48 | }
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49 | } else if (c == '\'') {
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50 | if (start == -1) {
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51 | result.append(c);
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52 | }
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53 | } else {
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54 | if (start != -1) {
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55 | result.append(stem(str.substring(start, j)));
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56 | start = -1;
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57 | }
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58 | result.append(c);
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59 | }
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60 | }
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61 | if (start != -1) {
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62 | result.append(stem(str.substring(start, str.length())));
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63 | }
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64 | return result.toString();
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65 | }
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66 | }
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67 |
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68 |
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