Java tutorial
/* * 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.search.spell; import org.apache.lucene.index.IndexReader; import org.apache.lucene.index.MultiTerms; import org.apache.lucene.search.suggest.InputIterator; import org.apache.lucene.index.Terms; import java.io.*; /** * Lucene Dictionary: terms taken from the given field * of a Lucene index. */ public class LuceneDictionary implements Dictionary { private IndexReader reader; private String field; /** * Creates a new Dictionary, pulling source terms from * the specified <code>field</code> in the provided <code>reader</code> */ public LuceneDictionary(IndexReader reader, String field) { this.reader = reader; this.field = field; } @Override public final InputIterator getEntryIterator() throws IOException { final Terms terms = MultiTerms.getTerms(reader, field); if (terms != null) { return new InputIterator.InputIteratorWrapper(terms.iterator()); } else { return InputIterator.EMPTY; } } }