/*
* 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.
*/
package org.apache.lucene.analysis.ngram;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.MockTokenizer;
import org.apache.lucene.analysis.TokenFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.BaseTokenStreamTestCase;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.core.KeywordTokenizer;
import org.apache.lucene.analysis.core.WhitespaceTokenizer;
import org.apache.lucene.analysis.miscellaneous.ASCIIFoldingFilter;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.util.TestUtil;
import java.io.IOException;
import java.io.StringReader;
import java.util.Random;
/**
* Tests {@link NGramTokenFilter} for correctness.
*/
public class NGramTokenFilterTest extends BaseTokenStreamTestCase {
private TokenStream input;
@Override
public void setUp() throws Exception {
super.setUp();
input = whitespaceMockTokenizer("abcde");
}
public void testInvalidInput() throws Exception {
expectThrows(IllegalArgumentException.class, () -> {
new NGramTokenFilter(input, 2, 1);
});
}
public void testInvalidInput2() throws Exception {
expectThrows(IllegalArgumentException.class, () -> {
new NGramTokenFilter(input, 0, 1);
});
}
public void testUnigrams() throws Exception {
NGramTokenFilter filter = new NGramTokenFilter(input, 1, 1);
assertTokenStreamContents(filter, new String[]{"a","b","c","d","e"}, new int[]{0,0,0,0,0}, new int[]{5,5,5,5,5}, new int[]{1,0,0,0,0});
}
public void testBigrams() throws Exception {
NGramTokenFilter filter = new NGramTokenFilter(input, 2, 2);
assertTokenStreamContents(filter, new String[]{"ab","bc","cd","de"}, new int[]{0,0,0,0}, new int[]{5,5,5,5}, new int[]{1,0,0,0});
}
public void testNgrams() throws Exception {
NGramTokenFilter filter = new NGramTokenFilter(input, 1, 3);
assertTokenStreamContents(filter,
new String[]{"a","ab","abc","b","bc","bcd","c","cd","cde","d","de","e"},
new int[]{0,0,0,0,0,0,0,0,0,0,0,0},
new int[]{5,5,5,5,5,5,5,5,5,5,5,5},
null,
new int[]{1,0,0,0,0,0,0,0,0,0,0,0},
null, null, false
);
}
public void testNgramsNoIncrement() throws Exception {
NGramTokenFilter filter = new NGramTokenFilter(input, 1, 3);
assertTokenStreamContents(filter,
new String[]{"a","ab","abc","b","bc","bcd","c","cd","cde","d","de","e"},
new int[]{0,0,0,0,0,0,0,0,0,0,0,0},
new int[]{5,5,5,5,5,5,5,5,5,5,5,5},
null,
new int[]{1,0,0,0,0,0,0,0,0,0,0,0},
null, null, false
);
}
public void testOversizedNgrams() throws Exception {
NGramTokenFilter filter = new NGramTokenFilter(input, 6, 7);
assertTokenStreamContents(filter, new String[0], new int[0], new int[0]);
}
public void testSmallTokenInStream() throws Exception {
input = whitespaceMockTokenizer("abc de fgh");
NGramTokenFilter filter = new NGramTokenFilter(input, 3, 3);
assertTokenStreamContents(filter, new String[]{"abc","fgh"}, new int[]{0,7}, new int[]{3,10}, new int[] {1, 2});
}
public void testReset() throws Exception {
WhitespaceTokenizer tokenizer = new WhitespaceTokenizer();
tokenizer.setReader(new StringReader("abcde"));
NGramTokenFilter filter = new NGramTokenFilter(tokenizer, 1, 1);
assertTokenStreamContents(filter, new String[]{"a","b","c","d","e"}, new int[]{0,0,0,0,0}, new int[]{5,5,5,5,5}, new int[]{1,0,0,0,0});
tokenizer.setReader(new StringReader("abcde"));
assertTokenStreamContents(filter, new String[]{"a","b","c","d","e"}, new int[]{0,0,0,0,0}, new int[]{5,5,5,5,5}, new int[]{1,0,0,0,0});
}
// LUCENE-3642
// EdgeNgram blindly adds term length to offset, but this can take things out of bounds
// wrt original text if a previous filter increases the length of the word (in this case æ -> ae)
// so in this case we behave like WDF, and preserve any modified offsets
public void testInvalidOffsets() throws Exception {
Analyzer analyzer = new Analyzer() {
@Override
protected TokenStreamComponents createComponents(String fieldName) {
Tokenizer tokenizer = new MockTokenizer(MockTokenizer.WHITESPACE, false);
TokenFilter filters = new ASCIIFoldingFilter(tokenizer);
filters = new NGramTokenFilter(filters, 2, 2);
return new TokenStreamComponents(tokenizer, filters);
}
};
assertAnalyzesTo(analyzer, "mosfellsbær",
new String[] { "mo", "os", "sf", "fe", "el", "ll", "ls", "sb", "ba", "ae", "er" },
new int[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
new int[] { 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11 },
new int[] { 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 });
analyzer.close();
}
/** blast some random strings through the analyzer */
public void testRandomStrings() throws Exception {
for (int i = 0; i < 10; i++) {
final int min = TestUtil.nextInt(random(), 2, 10);
final int max = TestUtil.nextInt(random(), min, 20);
Analyzer a = new Analyzer() {
@Override
protected TokenStreamComponents createComponents(String fieldName) {
Tokenizer tokenizer = new MockTokenizer(MockTokenizer.WHITESPACE, false);
return new TokenStreamComponents(tokenizer,
new NGramTokenFilter(tokenizer, min, max));
}
};
checkRandomData(random(), a, 200*RANDOM_MULTIPLIER, 20);
a.close();
}
}
public void testEmptyTerm() throws Exception {
Random random = random();
Analyzer a = new Analyzer() {
@Override
protected TokenStreamComponents createComponents(String fieldName) {
Tokenizer tokenizer = new KeywordTokenizer();
return new TokenStreamComponents(tokenizer,
new NGramTokenFilter(tokenizer, 2, 15));
}
};
checkAnalysisConsistency(random, a, random.nextBoolean(), "");
a.close();
}
public void testSupplementaryCharacters() throws IOException {
final String s = TestUtil.randomUnicodeString(random(), 10);
final int codePointCount = s.codePointCount(0, s.length());
final int minGram = TestUtil.nextInt(random(), 1, 3);
final int maxGram = TestUtil.nextInt(random(), minGram, 10);
TokenStream tk = new KeywordTokenizer();
((Tokenizer)tk).setReader(new StringReader(s));
tk = new NGramTokenFilter(tk, minGram, maxGram);
final CharTermAttribute termAtt = tk.addAttribute(CharTermAttribute.class);
final OffsetAttribute offsetAtt = tk.addAttribute(OffsetAttribute.class);
tk.reset();
for (int start = 0; start < codePointCount; ++start) {
for (int end = start + minGram; end <= Math.min(codePointCount, start + maxGram); ++end) {
assertTrue(tk.incrementToken());
assertEquals(0, offsetAtt.startOffset());
assertEquals(s.length(), offsetAtt.endOffset());
final int startIndex = Character.offsetByCodePoints(s, 0, start);
final int endIndex = Character.offsetByCodePoints(s, 0, end);
assertEquals(s.substring(startIndex, endIndex), termAtt.toString());
}
}
assertFalse(tk.incrementToken());
}
}