+++ /dev/null
-package org.apache.lucene.analysis.id;
-
-/**
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-import static org.apache.lucene.analysis.util.StemmerUtil.*;
-
-/**
- * Stemmer for Indonesian.
- * <p>
- * Stems Indonesian words with the algorithm presented in:
- * <i>A Study of Stemming Effects on Information Retrieval in
- * Bahasa Indonesia</i>, Fadillah Z Tala.
- * http://www.illc.uva.nl/Publications/ResearchReports/MoL-2003-02.text.pdf
- */
-public class IndonesianStemmer {
- private int numSyllables;
- private int flags;
- private static final int REMOVED_KE = 1;
- private static final int REMOVED_PENG = 2;
- private static final int REMOVED_DI = 4;
- private static final int REMOVED_MENG = 8;
- private static final int REMOVED_TER = 16;
- private static final int REMOVED_BER = 32;
- private static final int REMOVED_PE = 64;
-
- /**
- * Stem a term (returning its new length).
- * <p>
- * Use <code>stemDerivational</code> to control whether full stemming
- * or only light inflectional stemming is done.
- */
- public int stem(char text[], int length, boolean stemDerivational) {
- flags = 0;
- numSyllables = 0;
- for (int i = 0; i < length; i++)
- if (isVowel(text[i]))
- numSyllables++;
-
- if (numSyllables > 2) length = removeParticle(text, length);
- if (numSyllables > 2) length = removePossessivePronoun(text, length);
-
- if (stemDerivational)
- length = stemDerivational(text, length);
- return length;
- }
-
- private int stemDerivational(char text[], int length) {
- int oldLength = length;
- if (numSyllables > 2) length = removeFirstOrderPrefix(text, length);
- if (oldLength != length) { // a rule is fired
- oldLength = length;
- if (numSyllables > 2) length = removeSuffix(text, length);
- if (oldLength != length) // a rule is fired
- if (numSyllables > 2) length = removeSecondOrderPrefix(text, length);
- } else { // fail
- if (numSyllables > 2) length = removeSecondOrderPrefix(text, length);
- if (numSyllables > 2) length = removeSuffix(text, length);
- }
- return length;
- }
-
- private boolean isVowel(char ch) {
- switch(ch) {
- case 'a':
- case 'e':
- case 'i':
- case 'o':
- case 'u':
- return true;
- default:
- return false;
- }
- }
-
- private int removeParticle(char text[], int length) {
- if (endsWith(text, length, "kah") ||
- endsWith(text, length, "lah") ||
- endsWith(text, length, "pun")) {
- numSyllables--;
- return length - 3;
- }
-
- return length;
- }
-
- private int removePossessivePronoun(char text[], int length) {
- if (endsWith(text, length, "ku") || endsWith(text, length, "mu")) {
- numSyllables--;
- return length - 2;
- }
-
- if (endsWith(text, length, "nya")) {
- numSyllables--;
- return length - 3;
- }
-
- return length;
- }
-
- private int removeFirstOrderPrefix(char text[], int length) {
- if (startsWith(text, length, "meng")) {
- flags |= REMOVED_MENG;
- numSyllables--;
- return deleteN(text, 0, length, 4);
- }
-
- if (startsWith(text, length, "meny") && length > 4 && isVowel(text[4])) {
- flags |= REMOVED_MENG;
- text[3] = 's';
- numSyllables--;
- return deleteN(text, 0, length, 3);
- }
-
- if (startsWith(text, length, "men")) {
- flags |= REMOVED_MENG;
- numSyllables--;
- return deleteN(text, 0, length, 3);
- }
-
- if (startsWith(text, length, "mem")) {
- flags |= REMOVED_MENG;
- numSyllables--;
- return deleteN(text, 0, length, 3);
- }
-
- if (startsWith(text, length, "me")) {
- flags |= REMOVED_MENG;
- numSyllables--;
- return deleteN(text, 0, length, 2);
- }
-
- if (startsWith(text, length, "peng")) {
- flags |= REMOVED_PENG;
- numSyllables--;
- return deleteN(text, 0, length, 4);
- }
-
- if (startsWith(text, length, "peny") && length > 4 && isVowel(text[4])) {
- flags |= REMOVED_PENG;
- text[3] = 's';
- numSyllables--;
- return deleteN(text, 0, length, 3);
- }
-
- if (startsWith(text, length, "peny")) {
- flags |= REMOVED_PENG;
- numSyllables--;
- return deleteN(text, 0, length, 4);
- }
-
- if (startsWith(text, length, "pen") && length > 3 && isVowel(text[3])) {
- flags |= REMOVED_PENG;
- text[2] = 't';
- numSyllables--;
- return deleteN(text, 0, length, 2);
- }
-
- if (startsWith(text, length, "pen")) {
- flags |= REMOVED_PENG;
- numSyllables--;
- return deleteN(text, 0, length, 3);
- }
-
- if (startsWith(text, length, "pem")) {
- flags |= REMOVED_PENG;
- numSyllables--;
- return deleteN(text, 0, length, 3);
- }
-
- if (startsWith(text, length, "di")) {
- flags |= REMOVED_DI;
- numSyllables--;
- return deleteN(text, 0, length, 2);
- }
-
- if (startsWith(text, length, "ter")) {
- flags |= REMOVED_TER;
- numSyllables--;
- return deleteN(text, 0, length, 3);
- }
-
- if (startsWith(text, length, "ke")) {
- flags |= REMOVED_KE;
- numSyllables--;
- return deleteN(text, 0, length, 2);
- }
-
- return length;
- }
-
- private int removeSecondOrderPrefix(char text[], int length) {
- if (startsWith(text, length, "ber")) {
- flags |= REMOVED_BER;
- numSyllables--;
- return deleteN(text, 0, length, 3);
- }
-
- if (length == 7 && startsWith(text, length, "belajar")) {
- flags |= REMOVED_BER;
- numSyllables--;
- return deleteN(text, 0, length, 3);
- }
-
- if (startsWith(text, length, "be") && length > 4
- && !isVowel(text[2]) && text[3] == 'e' && text[4] == 'r') {
- flags |= REMOVED_BER;
- numSyllables--;
- return deleteN(text, 0, length, 2);
- }
-
- if (startsWith(text, length, "per")) {
- numSyllables--;
- return deleteN(text, 0, length, 3);
- }
-
- if (length == 7 && startsWith(text, length, "pelajar")) {
- numSyllables--;
- return deleteN(text, 0, length, 3);
- }
-
- if (startsWith(text, length, "pe")) {
- flags |= REMOVED_PE;
- numSyllables--;
- return deleteN(text, 0, length, 2);
- }
-
- return length;
- }
-
- private int removeSuffix(char text[], int length) {
- if (endsWith(text, length, "kan")
- && (flags & REMOVED_KE) == 0
- && (flags & REMOVED_PENG) == 0
- && (flags & REMOVED_PE) == 0) {
- numSyllables--;
- return length - 3;
- }
-
- if (endsWith(text, length, "an")
- && (flags & REMOVED_DI) == 0
- && (flags & REMOVED_MENG) == 0
- && (flags & REMOVED_TER) == 0) {
- numSyllables--;
- return length - 2;
- }
-
- if (endsWith(text, length, "i")
- && !endsWith(text, length, "si")
- && (flags & REMOVED_BER) == 0
- && (flags & REMOVED_KE) == 0
- && (flags & REMOVED_PENG) == 0) {
- numSyllables--;
- return length - 1;
- }
- return length;
- }
-}
fnp / pylucene.git / blobdiff