/*
* 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 java.io.IOException;
import java.io.StringReader;
import java.util.Random;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.BaseTokenStreamTestCase;
import org.apache.lucene.analysis.MockTokenizer;
import org.apache.lucene.analysis.TokenFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.core.KeywordTokenizer;
import org.apache.lucene.analysis.core.LetterTokenizer;
import org.apache.lucene.analysis.core.WhitespaceTokenizer;
import org.apache.lucene.analysis.shingle.ShingleFilter;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
import org.apache.lucene.util.TestUtil;
/**
* Tests {@link EdgeNGramTokenFilter} for correctness.
*/
public class EdgeNGramTokenFilterTest 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 EdgeNGramTokenFilter(input, 0, 0);
});
}
public void testInvalidInput2() throws Exception {
expectThrows(IllegalArgumentException.class, () -> {
new EdgeNGramTokenFilter(input, 2, 1);
});
}
public void testInvalidInput3() throws Exception {
expectThrows(IllegalArgumentException.class, () -> {
new EdgeNGramTokenFilter(input, -1, 2);
});
}
public void testFrontUnigram() throws Exception {
EdgeNGramTokenFilter tokenizer = new EdgeNGramTokenFilter(input, 1, 1);
assertTokenStreamContents(tokenizer, new String[]{"a"}, new int[]{0}, new int[]{5});
}
public void testOversizedNgrams() throws Exception {
EdgeNGramTokenFilter tokenizer = new EdgeNGramTokenFilter(input, 6, 6);
assertTokenStreamContents(tokenizer, new String[0], new int[0], new int[0]);
}
public void testFrontRangeOfNgrams() throws Exception {
EdgeNGramTokenFilter tokenizer = new EdgeNGramTokenFilter(input, 1, 3);
assertTokenStreamContents(tokenizer, new String[]{"a","ab","abc"}, new int[]{0,0,0}, new int[]{5,5,5});
}
public void testFilterPositions() throws Exception {
TokenStream ts = whitespaceMockTokenizer("abcde vwxyz");
EdgeNGramTokenFilter tokenizer = new EdgeNGramTokenFilter(ts, 1, 3);
assertTokenStreamContents(tokenizer,
new String[]{"a","ab","abc","v","vw","vwx"},
new int[]{0,0,0,6,6,6},
new int[]{5,5,5,11,11,11},
null,
new int[]{1,0,0,1,0,0},
null,
null,
false);
}
private static class PositionFilter extends TokenFilter {
private final PositionIncrementAttribute posIncrAtt = addAttribute(PositionIncrementAttribute.class);
private boolean started;
PositionFilter(final TokenStream input) {
super(input);
}
@Override
public final boolean incrementToken() throws IOException {
if (input.incrementToken()) {
if (started) {
posIncrAtt.setPositionIncrement(0);
} else {
started = true;
}
return true;
} else {
return false;
}
}
@Override
public void reset() throws IOException {
super.reset();
started = false;
}
}
public void testFirstTokenPositionIncrement() throws Exception {
TokenStream ts = whitespaceMockTokenizer("a abc");
ts = new PositionFilter(ts); // All but first token will get 0 position increment
EdgeNGramTokenFilter filter = new EdgeNGramTokenFilter(ts, 2, 3);
// The first token "a" will not be output, since it's smaller than the mingram size of 2.
// The second token on input to EdgeNGramTokenFilter will have position increment of 0,
// which should be increased to 1, since this is the first output token in the stream.
assertTokenStreamContents(filter,
new String[] { "ab", "abc" },
new int[] { 2, 2 },
new int[] { 5, 5 },
new int[] { 1, 0 }
);
}
public void testSmallTokenInStream() throws Exception {
input = whitespaceMockTokenizer("abc de fgh");
EdgeNGramTokenFilter tokenizer = new EdgeNGramTokenFilter(input, 3, 3);
assertTokenStreamContents(tokenizer, new String[]{"abc","fgh"}, new int[]{0,7}, new int[]{3,10});
}
public void testReset() throws Exception {
WhitespaceTokenizer tokenizer = new WhitespaceTokenizer();
tokenizer.setReader(new StringReader("abcde"));
EdgeNGramTokenFilter filter = new EdgeNGramTokenFilter(tokenizer, 1, 3);
assertTokenStreamContents(filter, new String[]{"a","ab","abc"}, new int[]{0,0,0}, new int[]{5,5,5});
tokenizer.setReader(new StringReader("abcde"));
assertTokenStreamContents(filter, new String[]{"a","ab","abc"}, new int[]{0,0,0}, new int[]{5,5,5});
}
/** 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 EdgeNGramTokenFilter(tokenizer, min, max));
}
};
checkRandomData(random(), a, 100*RANDOM_MULTIPLIER);
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 EdgeNGramTokenFilter(tokenizer, 2, 15));
}
};
checkAnalysisConsistency(random, a, random.nextBoolean(), "");
a.close();
}
public void testGraphs() throws IOException {
TokenStream tk = new LetterTokenizer();
((Tokenizer)tk).setReader(new StringReader("abc d efgh ij klmno p q"));
tk = new ShingleFilter(tk);
tk = new EdgeNGramTokenFilter(tk, 7, 10);
assertTokenStreamContents(tk,
new String[] { "efgh ij", "ij klmn", "ij klmno", "klmno p" },
new int[] { 6,11,11,14 },
new int[] { 13,19,19,21 },
new int[] { 3,1,0,1 },
new int[] { 2,2,2,2 },
23
);
}
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 EdgeNGramTokenFilter(tk, minGram, maxGram);
final CharTermAttribute termAtt = tk.addAttribute(CharTermAttribute.class);
final OffsetAttribute offsetAtt = tk.addAttribute(OffsetAttribute.class);
tk.reset();
for (int i = minGram; i <= Math.min(codePointCount, maxGram); ++i) {
assertTrue(tk.incrementToken());
assertEquals(0, offsetAtt.startOffset());
assertEquals(s.length(), offsetAtt.endOffset());
final int end = Character.offsetByCodePoints(s, 0, i);
assertEquals(s.substring(0, end), termAtt.toString());
}
assertFalse(tk.incrementToken());
}
}