org.apache.lucene.codecs.blockterms.LuceneVarGapFixedInterval.java Source code

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Here is the source code for org.apache.lucene.codecs.blockterms.LuceneVarGapFixedInterval.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.codecs.blockterms;

import java.io.IOException;

import org.apache.lucene.codecs.FieldsConsumer;
import org.apache.lucene.codecs.FieldsProducer;
import org.apache.lucene.codecs.PostingsFormat;
import org.apache.lucene.codecs.PostingsReaderBase;
import org.apache.lucene.codecs.PostingsWriterBase;
import org.apache.lucene.codecs.lucene50.Lucene50PostingsFormat; // javadocs
import org.apache.lucene.codecs.lucene50.Lucene50PostingsReader;
import org.apache.lucene.codecs.lucene50.Lucene50PostingsWriter;
import org.apache.lucene.index.SegmentReadState;
import org.apache.lucene.index.SegmentWriteState;

// TODO: we could make separate base class that can wrap
// any PostingsFormat and make it ord-able...

/**
 * Customized version of {@link Lucene50PostingsFormat} that uses
 * {@link VariableGapTermsIndexWriter} with a fixed interval.
 */
public final class LuceneVarGapFixedInterval extends PostingsFormat {
    final int termIndexInterval;

    public LuceneVarGapFixedInterval() {
        this(FixedGapTermsIndexWriter.DEFAULT_TERM_INDEX_INTERVAL);
    }

    public LuceneVarGapFixedInterval(int termIndexInterval) {
        super("LuceneVarGapFixedInterval");
        this.termIndexInterval = termIndexInterval;
    }

    @Override
    public FieldsConsumer fieldsConsumer(SegmentWriteState state) throws IOException {
        PostingsWriterBase docs = new Lucene50PostingsWriter(state);

        // TODO: should we make the terms index more easily
        // pluggable?  Ie so that this codec would record which
        // index impl was used, and switch on loading?
        // Or... you must make a new Codec for this?
        TermsIndexWriterBase indexWriter;
        boolean success = false;
        try {
            indexWriter = new VariableGapTermsIndexWriter(state,
                    new VariableGapTermsIndexWriter.EveryNTermSelector(termIndexInterval));
            success = true;
        } finally {
            if (!success) {
                docs.close();
            }
        }

        success = false;
        try {
            // Must use BlockTermsWriter (not BlockTree) because
            // BlockTree doens't support ords (yet)...
            FieldsConsumer ret = new BlockTermsWriter(indexWriter, state, docs);
            success = true;
            return ret;
        } finally {
            if (!success) {
                try {
                    docs.close();
                } finally {
                    indexWriter.close();
                }
            }
        }
    }

    @Override
    public FieldsProducer fieldsProducer(SegmentReadState state) throws IOException {
        PostingsReaderBase postings = new Lucene50PostingsReader(state);
        TermsIndexReaderBase indexReader;

        boolean success = false;
        try {
            indexReader = new VariableGapTermsIndexReader(state);
            success = true;
        } finally {
            if (!success) {
                postings.close();
            }
        }

        success = false;
        try {
            FieldsProducer ret = new BlockTermsReader(indexReader, postings, state);
            success = true;
            return ret;
        } finally {
            if (!success) {
                try {
                    postings.close();
                } finally {
                    indexReader.close();
                }
            }
        }
    }

    /** Extension of freq postings file */
    static final String FREQ_EXTENSION = "frq";

    /** Extension of prox postings file */
    static final String PROX_EXTENSION = "prx";
}