org.alfresco.solr.query.DocValuesCache.java Source code

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Here is the source code for org.alfresco.solr.query.DocValuesCache.java

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/*
 * Copyright (C) 2005-2012 Alfresco Software Limited.
 *
 * This file is part of Alfresco
 *
 * Alfresco is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Alfresco is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with Alfresco. If not, see <http://www.gnu.org/licenses/>.
 */

package org.alfresco.solr.query;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.WeakHashMap;

import org.apache.lucene.index.LeafReader;
import org.apache.lucene.index.NumericDocValues;

/**
 * The DocValuesCache is an in-memory uncompressed numeric DocValues cache. It is designed to provide the fastest
 * possible access to numeric docValues. The DocValuesCache can be used instead of the Direct DocValues format which also
 * provides uncompressed in-memory docValues. The DocValuesCache can be used in situations when it is not
 * practical to re-index to use Direct docValues.
 **/

public class DocValuesCache {
    private static Map<String, WeakHashMap<Object, NumericDocValues>> cache = new HashMap<String, WeakHashMap<Object, NumericDocValues>>();

    public static synchronized NumericDocValues getNumericDocValues(String field, LeafReader reader)
            throws IOException {
        WeakHashMap<Object, NumericDocValues> fieldCache = cache.get(field);

        if (fieldCache == null) {
            fieldCache = new WeakHashMap<Object, NumericDocValues>();
            cache.put(field, fieldCache);
        }

        Object cacheKey = reader.getCoreCacheKey();
        NumericDocValues cachedValues = fieldCache.get(cacheKey);

        if (cachedValues == null) {
            NumericDocValues fieldValues = reader.getNumericDocValues(field);
            if (fieldValues == null) {
                return null;
            } else {
                int maxDoc = reader.maxDoc();
                boolean longs = false;
                int[] intValues = new int[maxDoc]; //Always start off with an int array.
                SettableDocValues settableValues = new IntValues(intValues);

                for (int i = 0; i < maxDoc; i++) {
                    long value = fieldValues.get(i);
                    if (value > Integer.MAX_VALUE && !longs) {
                        longs = true;
                        settableValues = new LongValues(intValues);
                    }

                    settableValues.set(i, value);
                }
                fieldCache.put(cacheKey, settableValues);
                return settableValues;
            }
        } else {
            return cachedValues;
        }
    }

    private static abstract class SettableDocValues extends NumericDocValues {
        public abstract void set(int index, long value);
    }

    private static class IntValues extends SettableDocValues {
        private int[] values;

        public IntValues(int[] values) {
            this.values = values;
        }

        public void set(int index, long value) {
            this.values[index] = (int) value;
        }

        public long get(int index) {
            return values[index];
        }
    }

    private static class LongValues extends SettableDocValues {
        private long[] values;

        public LongValues(int[] ivalues) {
            values = new long[ivalues.length];
            for (int i = 0; i < ivalues.length; i++) {
                values[i] = ivalues[i];
            }
        }

        public void set(int index, long value) {
            this.values[index] = value;
        }

        public long get(int index) {
            return values[index];
        }
    }
}