org.elasticsearch.index.field.data.strings.StringOrdValFieldDataComparator Maven / Gradle / Ivy

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/*
 * Licensed to Elastic Search and Shay Banon under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. Elastic Search 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.elasticsearch.index.field.data.strings;

import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.FieldComparator;
import org.elasticsearch.index.cache.field.data.FieldDataCache;
import org.elasticsearch.index.field.data.FieldData;
import org.elasticsearch.index.field.data.FieldDataType;

import java.io.IOException;

/**
 * @author kimchy (shay.banon)
 */
// LUCENE MONITOR: Monitor against FieldComparator#String
public class StringOrdValFieldDataComparator extends FieldComparator {

    private final FieldDataCache fieldDataCache;

    private final int[] ords;
    private final String[] values;
    private final int[] readerGen;

    private int currentReaderGen = -1;
    private String[] lookup;
    private int[] order;
    private final String field;

    private int bottomSlot = -1;
    private int bottomOrd;
    private String bottomValue;
    private final boolean reversed;
    private final int sortPos;

    public StringOrdValFieldDataComparator(int numHits, String field, int sortPos, boolean reversed, FieldDataCache fieldDataCache) {
        this.fieldDataCache = fieldDataCache;
        ords = new int[numHits];
        values = new String[numHits];
        readerGen = new int[numHits];
        this.sortPos = sortPos;
        this.reversed = reversed;
        this.field = field;
    }

    @Override public int compare(int slot1, int slot2) {
        if (readerGen[slot1] == readerGen[slot2]) {
            int cmp = ords[slot1] - ords[slot2];
            if (cmp != 0) {
                return cmp;
            }
        }

        final String val1 = values[slot1];
        final String val2 = values[slot2];
        if (val1 == null) {
            if (val2 == null) {
                return 0;
            }
            return -1;
        } else if (val2 == null) {
            return 1;
        }
        return val1.compareTo(val2);
    }

    @Override public int compareBottom(int doc) {
        assert bottomSlot != -1;
        int order = this.order[doc];
        final int cmp = bottomOrd - order;
        if (cmp != 0) {
            return cmp;
        }

        final String val2 = lookup[order];
        if (bottomValue == null) {
            if (val2 == null) {
                return 0;
            }
            // bottom wins
            return -1;
        } else if (val2 == null) {
            // doc wins
            return 1;
        }
        return bottomValue.compareTo(val2);
    }

    private void convert(int slot) {
        readerGen[slot] = currentReaderGen;
        int index = 0;
        String value = values[slot];
        if (value == null) {
            ords[slot] = 0;
            return;
        }

        if (sortPos == 0 && bottomSlot != -1 && bottomSlot != slot) {
            // Since we are the primary sort, the entries in the
            // queue are bounded by bottomOrd:
            assert bottomOrd < lookup.length;
            if (reversed) {
                index = binarySearch(lookup, value, bottomOrd, lookup.length - 1);
            } else {
                index = binarySearch(lookup, value, 0, bottomOrd);
            }
        } else {
            // Full binary search
            index = binarySearch(lookup, value);
        }

        if (index < 0) {
            index = -index - 2;
        }
        ords[slot] = index;
    }

    @Override public void copy(int slot, int doc) {
        final int ord = order[doc];
        ords[slot] = ord;
        assert ord >= 0;
        values[slot] = lookup[ord];
        readerGen[slot] = currentReaderGen;
    }

    @Override public void setNextReader(IndexReader reader, int docBase) throws IOException {
        FieldData cleanFieldData = fieldDataCache.cache(FieldDataType.DefaultTypes.STRING, reader, field);
        if (cleanFieldData instanceof MultiValueStringFieldData) {
            throw new IOException("Can't sort on string types with more than one value per doc, or more than one token per field");
        }
        SingleValueStringFieldData fieldData = (SingleValueStringFieldData) cleanFieldData;
        currentReaderGen++;
        order = fieldData.order();
        lookup = fieldData.values();
        assert lookup.length > 0;
        if (bottomSlot != -1) {
            convert(bottomSlot);
            bottomOrd = ords[bottomSlot];
        }
    }

    @Override public void setBottom(final int bottom) {
        bottomSlot = bottom;
        if (readerGen[bottom] != currentReaderGen) {
            convert(bottomSlot);
        }
        bottomOrd = ords[bottom];
        assert bottomOrd >= 0;
        assert bottomOrd < lookup.length;
        bottomValue = values[bottom];
    }

    @Override public Comparable value(int slot) {
        return values[slot];
    }

    public String[] getValues() {
        return values;
    }

    public int getBottomSlot() {
        return bottomSlot;
    }

    public String getField() {
        return field;
    }

}