org.apache.lucene.index.FieldInvertState.java Source code

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Here is the source code for org.apache.lucene.index.FieldInvertState.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.index;

import org.apache.lucene.analysis.TokenStream; // javadocs
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.analysis.tokenattributes.PayloadAttribute;
import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
import org.apache.lucene.analysis.tokenattributes.TermFrequencyAttribute;
import org.apache.lucene.analysis.tokenattributes.TermToBytesRefAttribute;
import org.apache.lucene.util.AttributeSource;

/**
 * This class tracks the number and position / offset parameters of terms
 * being added to the index. The information collected in this class is
 * also used to calculate the normalization factor for a field.
 * 
 * @lucene.experimental
 */
public final class FieldInvertState {
    final int indexCreatedVersionMajor;
    final String name;
    final IndexOptions indexOptions;
    int position;
    int length;
    int numOverlap;
    int offset;
    int maxTermFrequency;
    int uniqueTermCount;
    // we must track these across field instances (multi-valued case)
    int lastStartOffset = 0;
    int lastPosition = 0;
    AttributeSource attributeSource;

    OffsetAttribute offsetAttribute;
    PositionIncrementAttribute posIncrAttribute;
    PayloadAttribute payloadAttribute;
    TermToBytesRefAttribute termAttribute;
    TermFrequencyAttribute termFreqAttribute;

    /** Creates {code FieldInvertState} for the specified
     *  field name. */
    public FieldInvertState(int indexCreatedVersionMajor, String name, IndexOptions indexOptions) {
        this.indexCreatedVersionMajor = indexCreatedVersionMajor;
        this.name = name;
        this.indexOptions = indexOptions;
    }

    /** Creates {code FieldInvertState} for the specified
     *  field name and values for all fields. */
    public FieldInvertState(int indexCreatedVersionMajor, String name, IndexOptions indexOptions, int position,
            int length, int numOverlap, int offset, int maxTermFrequency, int uniqueTermCount) {
        this(indexCreatedVersionMajor, name, indexOptions);
        this.position = position;
        this.length = length;
        this.numOverlap = numOverlap;
        this.offset = offset;
        this.maxTermFrequency = maxTermFrequency;
        this.uniqueTermCount = uniqueTermCount;
    }

    /**
     * Re-initialize the state
     */
    void reset() {
        position = -1;
        length = 0;
        numOverlap = 0;
        offset = 0;
        maxTermFrequency = 0;
        uniqueTermCount = 0;
        lastStartOffset = 0;
        lastPosition = 0;
    }

    // TODO: better name?
    /**
     * Sets attributeSource to a new instance.
     */
    void setAttributeSource(AttributeSource attributeSource) {
        if (this.attributeSource != attributeSource) {
            this.attributeSource = attributeSource;
            termAttribute = attributeSource.getAttribute(TermToBytesRefAttribute.class);
            termFreqAttribute = attributeSource.addAttribute(TermFrequencyAttribute.class);
            posIncrAttribute = attributeSource.addAttribute(PositionIncrementAttribute.class);
            offsetAttribute = attributeSource.addAttribute(OffsetAttribute.class);
            payloadAttribute = attributeSource.getAttribute(PayloadAttribute.class);
        }
    }

    /**
     * Get the last processed term position.
     * @return the position
     */
    public int getPosition() {
        return position;
    }

    /**
     * Get total number of terms in this field.
     * @return the length
     */
    public int getLength() {
        return length;
    }

    /** Set length value. */
    public void setLength(int length) {
        this.length = length;
    }

    /**
     * Get the number of terms with <code>positionIncrement == 0</code>.
     * @return the numOverlap
     */
    public int getNumOverlap() {
        return numOverlap;
    }

    /** Set number of terms with {@code positionIncrement ==
     *  0}. */
    public void setNumOverlap(int numOverlap) {
        this.numOverlap = numOverlap;
    }

    /**
     * Get end offset of the last processed term.
     * @return the offset
     */
    public int getOffset() {
        return offset;
    }

    /**
     * Get the maximum term-frequency encountered for any term in the field.  A
     * field containing "the quick brown fox jumps over the lazy dog" would have
     * a value of 2, because "the" appears twice.
     */
    public int getMaxTermFrequency() {
        return maxTermFrequency;
    }

    /**
     * Return the number of unique terms encountered in this field.
     */
    public int getUniqueTermCount() {
        return uniqueTermCount;
    }

    /** Returns the {@link AttributeSource} from the {@link
     *  TokenStream} that provided the indexed tokens for this
     *  field. */
    public AttributeSource getAttributeSource() {
        return attributeSource;
    }

    /**
     * Return the field's name
     */
    public String getName() {
        return name;
    }

    /**
     * Return the version that was used to create the index, or 6 if it was created before 7.0.
     */
    public int getIndexCreatedVersionMajor() {
        return indexCreatedVersionMajor;
    }

    /**
     * Get the index options for this field
     */
    public IndexOptions getIndexOptions() {
        return indexOptions;
    }
}