package org.apache.lucene.analysis.ngram;
/**
* 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 org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.MockTokenizer;
import org.apache.lucene.analysis.ReusableAnalyzerBase;
import org.apache.lucene.analysis.TokenFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.WhitespaceTokenizer;
import org.apache.lucene.analysis.BaseTokenStreamTestCase;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.ASCIIFoldingFilter;
import org.apache.lucene.analysis.KeywordTokenizer;
import java.io.Reader;
import java.io.StringReader;
/**
* Tests {@link NGramTokenFilter} for correctness.
*/
public class NGramTokenFilterTest extends BaseTokenStreamTestCase {
private TokenStream input;
@Override
public void setUp() throws Exception {
super.setUp();
input = new MockTokenizer(new StringReader("abcde"), MockTokenizer.WHITESPACE, false);
}
public void testInvalidInput() throws Exception {
boolean gotException = false;
try {
new NGramTokenFilter(input, 2, 1);
} catch (IllegalArgumentException e) {
gotException = true;
}
assertTrue(gotException);
}
public void testInvalidInput2() throws Exception {
boolean gotException = false;
try {
new NGramTokenFilter(input, 0, 1);
} catch (IllegalArgumentException e) {
gotException = true;
}
assertTrue(gotException);
}
public void testUnigrams() throws Exception {
NGramTokenFilter filter = new NGramTokenFilter(input, 1, 1);
assertTokenStreamContents(filter, new String[]{"a","b","c","d","e"}, new int[]{0,1,2,3,4}, new int[]{1,2,3,4,5});
}
public void testBigrams() throws Exception {
NGramTokenFilter filter = new NGramTokenFilter(input, 2, 2);
assertTokenStreamContents(filter, new String[]{"ab","bc","cd","de"}, new int[]{0,1,2,3}, new int[]{2,3,4,5});
}
public void testNgrams() throws Exception {
NGramTokenFilter filter = new NGramTokenFilter(input, 1, 3);
assertTokenStreamContents(filter,
new String[]{"a","b","c","d","e", "ab","bc","cd","de", "abc","bcd","cde"},
new int[]{0,1,2,3,4, 0,1,2,3, 0,1,2},
new int[]{1,2,3,4,5, 2,3,4,5, 3,4,5}
);
}
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 = new MockTokenizer(new StringReader("abc de fgh"), MockTokenizer.WHITESPACE, false);
NGramTokenFilter filter = new NGramTokenFilter(input, 3, 3);
assertTokenStreamContents(filter, new String[]{"abc","fgh"}, new int[]{0,7}, new int[]{3,10});
}
public void testReset() throws Exception {
WhitespaceTokenizer tokenizer = new WhitespaceTokenizer(TEST_VERSION_CURRENT, new StringReader("abcde"));
NGramTokenFilter filter = new NGramTokenFilter(tokenizer, 1, 1);
assertTokenStreamContents(filter, new String[]{"a","b","c","d","e"}, new int[]{0,1,2,3,4}, new int[]{1,2,3,4,5});
tokenizer.reset(new StringReader("abcde"));
assertTokenStreamContents(filter, new String[]{"a","b","c","d","e"}, new int[]{0,1,2,3,4}, new int[]{1,2,3,4,5});
}
// 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 ReusableAnalyzerBase() {
@Override
protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
Tokenizer tokenizer = new MockTokenizer(reader, 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 });
}
/** blast some random strings through the analyzer */
public void testRandomStrings() throws Exception {
Analyzer a = new ReusableAnalyzerBase() {
@Override
protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
Tokenizer tokenizer = new MockTokenizer(reader, MockTokenizer.WHITESPACE, false);
return new TokenStreamComponents(tokenizer,
new NGramTokenFilter(tokenizer, 2, 15));
}
};
checkRandomData(random, a, 10000*RANDOM_MULTIPLIER);
}
public void testEmptyTerm() throws Exception {
Analyzer a = new ReusableAnalyzerBase() {
@Override
protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
Tokenizer tokenizer = new KeywordTokenizer(reader);
return new TokenStreamComponents(tokenizer,
new NGramTokenFilter(tokenizer, 2, 15));
}
};
checkAnalysisConsistency(random, a, random.nextBoolean(), "");
}
}