org.apache.lucene.search.spell.PlainTextDictionary.java Source code

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Here is the source code for org.apache.lucene.search.spell.PlainTextDictionary.java

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/*
 * 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 java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;

import org.apache.lucene.search.suggest.InputIterator;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.BytesRefBuilder;
import org.apache.lucene.util.BytesRefIterator;
import org.apache.lucene.util.IOUtils;

/**
 * Dictionary represented by a text file.
 * 
 * <p>Format allowed: 1 word per line:<br>
 * word1<br>
 * word2<br>
 * word3<br>
 */
public class PlainTextDictionary implements Dictionary {

    private BufferedReader in;

    /**
     * Creates a dictionary based on a Path.
     * <p>
     * NOTE: content is treated as UTF-8
     */
    public PlainTextDictionary(Path path) throws IOException {
        in = Files.newBufferedReader(path, StandardCharsets.UTF_8);
    }

    /**
     * Creates a dictionary based on an inputstream.
     * <p>
     * NOTE: content is treated as UTF-8
     */
    public PlainTextDictionary(InputStream dictFile) {
        in = new BufferedReader(IOUtils.getDecodingReader(dictFile, StandardCharsets.UTF_8));
    }

    /**
     * Creates a dictionary based on a reader.
     */
    public PlainTextDictionary(Reader reader) {
        in = new BufferedReader(reader);
    }

    @Override
    public InputIterator getEntryIterator() throws IOException {
        return new InputIterator.InputIteratorWrapper(new FileIterator());
    }

    final class FileIterator implements BytesRefIterator {
        private boolean done = false;
        private final BytesRefBuilder spare = new BytesRefBuilder();

        @Override
        public BytesRef next() throws IOException {
            if (done) {
                return null;
            }
            boolean success = false;
            BytesRef result;
            try {
                String line;
                if ((line = in.readLine()) != null) {
                    spare.copyChars(line);
                    result = spare.get();
                } else {
                    done = true;
                    IOUtils.close(in);
                    result = null;
                }
                success = true;
            } finally {
                if (!success) {
                    IOUtils.closeWhileHandlingException(in);
                }
            }
            return result;
        }
    }
}