import org.apache.lucene.analysis.reverse.ReverseStringFilter; //导入依赖的package包/类
public void testBackwardsCompatibilityEdgeNgramTokenFilter() throws Exception {
    int iters = scaledRandomIntBetween(20, 100);
    for (int i = 0; i < iters; i++) {
        final Index index = new Index("test", "_na_");
        final String name = "ngr";
        Version v = randomVersion(random());
        Builder builder = newAnalysisSettingsBuilder().put("min_gram", 2).put("max_gram", 3);
        boolean reverse = random().nextBoolean();
        if (reverse) {
            builder.put("side", "back");
        }
        Settings settings = builder.build();
        Settings indexSettings = newAnalysisSettingsBuilder().put(IndexMetaData.SETTING_VERSION_CREATED, v.id).build();
        Tokenizer tokenizer = new MockTokenizer();
        tokenizer.setReader(new StringReader("foo bar"));
        TokenStream edgeNGramTokenFilter = new EdgeNGramTokenFilterFactory(IndexSettingsModule.newIndexSettings(index, indexSettings), null, name, settings).create(tokenizer);
        if (reverse) {
            assertThat(edgeNGramTokenFilter, instanceOf(ReverseStringFilter.class));
        } else {
            assertThat(edgeNGramTokenFilter, instanceOf(EdgeNGramTokenFilter.class));
        }
    }
}
 

import org.apache.lucene.analysis.reverse.ReverseStringFilter; //导入依赖的package包/类
@Override
public ReverseStringFilter create(TokenStream in) {
  if (luceneMatchVersion == null) {
    return new ReverseStringFilter(in);
  }
  return new ReverseStringFilter(luceneMatchVersion,in);
}
 

import org.apache.lucene.analysis.reverse.ReverseStringFilter; //导入依赖的package包/类
@Override
public TokenStream create(TokenStream tokenStream) {
    return new ReverseStringFilter(tokenStream);
}
 

import org.apache.lucene.analysis.reverse.ReverseStringFilter; //导入依赖的package包/类
@Override
protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
  final Tokenizer tokenizer = new KeywordTokenizer(reader);
  return new TokenStreamComponents(tokenizer, new ReverseStringFilter(new EdgeNGramTokenFilter(new ReverseStringFilter(tokenizer), 10, 20)));
}
 

import org.apache.lucene.analysis.reverse.ReverseStringFilter; //导入依赖的package包/类
@Override
public ReverseStringFilter create(TokenStream in) {
  assureMatchVersion();
  return new ReverseStringFilter(luceneMatchVersion,in);
}
 

import org.apache.lucene.analysis.reverse.ReverseStringFilter; //导入依赖的package包/类
@Override
public ReverseStringFilter create(TokenStream in) {
  return new ReverseStringFilter(luceneMatchVersion,in);
}
 

import org.apache.lucene.analysis.reverse.ReverseStringFilter; //导入依赖的package包/类
@Override
protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
  final Tokenizer tokenizer = new KeywordTokenizer(reader);
  return new TokenStreamComponents(tokenizer, new ReverseStringFilter(TEST_VERSION_CURRENT, new EdgeNGramTokenFilter(TEST_VERSION_CURRENT, new ReverseStringFilter(TEST_VERSION_CURRENT, tokenizer), 10, 20)));
}