org.apache.lucene.search.vectorhighlight.FieldFragList.java Source code

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Here is the source code for org.apache.lucene.search.vectorhighlight.FieldFragList.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.vectorhighlight;

import org.apache.lucene.search.vectorhighlight.FieldPhraseList.WeightedPhraseInfo;
import org.apache.lucene.search.vectorhighlight.FieldPhraseList.WeightedPhraseInfo.Toffs;

import java.util.ArrayList;
import java.util.List;

/**
 * FieldFragList has a list of "frag info" that is used by FragmentsBuilder class
 * to create fragments (snippets).
 */
public abstract class FieldFragList {

    private List<WeightedFragInfo> fragInfos = new ArrayList<>();

    /**
     * a constructor.
     * 
     * @param fragCharSize the length (number of chars) of a fragment
     */
    public FieldFragList(int fragCharSize) {
    }

    /**
     * convert the list of WeightedPhraseInfo to WeightedFragInfo, then add it to the fragInfos
     * 
     * @param startOffset start offset of the fragment
     * @param endOffset end offset of the fragment
     * @param phraseInfoList list of WeightedPhraseInfo objects
     */
    public abstract void add(int startOffset, int endOffset, List<WeightedPhraseInfo> phraseInfoList);

    /**
     * return the list of WeightedFragInfos.
     * 
     * @return fragInfos.
     */
    public List<WeightedFragInfo> getFragInfos() {
        return fragInfos;
    }

    /**
     * List of term offsets + weight for a frag info
     */
    public static class WeightedFragInfo {

        private List<SubInfo> subInfos;
        private float totalBoost;
        private int startOffset;
        private int endOffset;

        public WeightedFragInfo(int startOffset, int endOffset, List<SubInfo> subInfos, float totalBoost) {
            this.startOffset = startOffset;
            this.endOffset = endOffset;
            this.totalBoost = totalBoost;
            this.subInfos = subInfos;
        }

        public List<SubInfo> getSubInfos() {
            return subInfos;
        }

        public float getTotalBoost() {
            return totalBoost;
        }

        public int getStartOffset() {
            return startOffset;
        }

        public int getEndOffset() {
            return endOffset;
        }

        @Override
        public String toString() {
            StringBuilder sb = new StringBuilder();
            sb.append("subInfos=(");
            for (SubInfo si : subInfos)
                sb.append(si.toString());
            sb.append(")/").append(totalBoost).append('(').append(startOffset).append(',').append(endOffset)
                    .append(')');
            return sb.toString();
        }

        /**
         * Represents the list of term offsets for some text
         */
        public static class SubInfo {
            private final String text; // unnecessary member, just exists for debugging purpose
            private final List<Toffs> termsOffsets; // usually termsOffsets.size() == 1,
            // but if position-gap > 1 and slop > 0 then size() could be greater than 1
            private final int seqnum;
            private final float boost; // used for scoring split WeightedPhraseInfos.

            public SubInfo(String text, List<Toffs> termsOffsets, int seqnum, float boost) {
                this.text = text;
                this.termsOffsets = termsOffsets;
                this.seqnum = seqnum;
                this.boost = boost;
            }

            public List<Toffs> getTermsOffsets() {
                return termsOffsets;
            }

            public int getSeqnum() {
                return seqnum;
            }

            public String getText() {
                return text;
            }

            public float getBoost() {
                return boost;
            }

            @Override
            public String toString() {
                StringBuilder sb = new StringBuilder();
                sb.append(text).append('(');
                for (Toffs to : termsOffsets)
                    sb.append(to.toString());
                sb.append(')');
                return sb.toString();
            }
        }
    }
}