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HSQLDB example source code file (ValuePool.java)

This example HSQLDB source code file (ValuePool.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - HSQLDB tags/keywords

bigdecimal, bigdecimal, boolean, date, default_value_pool_size, default_value_pool_size, double, jdbc, long, math, pools_count, pools_count, sql, string, valuepool, valuepoolhashmap, valuepoolhashmap

The HSQLDB ValuePool.java source code

/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


package org.hsqldb.store;

import java.math.BigDecimal;
import java.sql.Date;

/**
  * Supports pooling of Integer, Long, Double, BigDecimal, String and Date
  * Java Objects. Leads to reduction in memory use when an Object is used more
  * then twice in the database.
  *
  * getXXX methods are used for retrival of values. If a value is not in
  * the pool, it is added to the pool and returned. When the pool gets
  * full, half the contents that have been accessed less recently are purged.
  *
  * @author fredt@users
  * @version 1.8.0
  * @since 1.7.2
  */
public class ValuePool {

    //
    static ValuePoolHashMap intPool;
    static ValuePoolHashMap longPool;
    static ValuePoolHashMap doublePool;
    static ValuePoolHashMap bigdecimalPool;
    static ValuePoolHashMap stringPool;
    static ValuePoolHashMap datePool;
    static final int        DEFAULT_VALUE_POOL_SIZE = 10000;
    static final int[]      defaultPoolLookupSize   = new int[] {
        DEFAULT_VALUE_POOL_SIZE, DEFAULT_VALUE_POOL_SIZE,
        DEFAULT_VALUE_POOL_SIZE, DEFAULT_VALUE_POOL_SIZE,
        DEFAULT_VALUE_POOL_SIZE, DEFAULT_VALUE_POOL_SIZE
    };
    static final int POOLS_COUNT            = defaultPoolLookupSize.length;
    static final int defaultSizeFactor      = 2;
    static final int defaultMaxStringLength = 16;

    //
    static ValuePoolHashMap[] poolList;

    //
    static int maxStringLength;

    //
    static {
        initPool();
    }

    private static void initPool() {

        int[] sizeArray  = defaultPoolLookupSize;
        int   sizeFactor = defaultSizeFactor;

        synchronized (ValuePool.class) {
            maxStringLength = defaultMaxStringLength;
            poolList        = new ValuePoolHashMap[POOLS_COUNT];

            for (int i = 0; i < POOLS_COUNT; i++) {
                int size = sizeArray[i];

                poolList[i] = new ValuePoolHashMap(size, size * sizeFactor,
                                                   BaseHashMap.PURGE_HALF);
            }

            intPool        = poolList[0];
            longPool       = poolList[1];
            doublePool     = poolList[2];
            bigdecimalPool = poolList[3];
            stringPool     = poolList[4];
            datePool       = poolList[5];
        }
    }

    public static void resetPool(int[] sizeArray, int sizeFactor) {

        synchronized (ValuePool.class) {
            for (int i = 0; i < POOLS_COUNT; i++) {
                poolList[i].resetCapacity(sizeArray[i] * sizeFactor,
                                          BaseHashMap.PURGE_HALF);
            }
        }
    }

    public static void resetPool() {

        synchronized (ValuePool.class) {
            resetPool(defaultPoolLookupSize, defaultSizeFactor);
        }
    }

    public static void clearPool() {

        synchronized (ValuePool.class) {
            for (int i = 0; i < POOLS_COUNT; i++) {
                poolList[i].clear();
            }
        }
    }

    public static Integer getInt(int val) {

        synchronized (intPool) {
            return intPool.getOrAddInteger(val);
        }
    }

    public static Long getLong(long val) {

        synchronized (longPool) {
            return longPool.getOrAddLong(val);
        }
    }

    public static Double getDouble(long val) {

        synchronized (doublePool) {
            return doublePool.getOrAddDouble(val);
        }
    }

    public static String getString(String val) {

        if (val == null || val.length() > maxStringLength) {
            return val;
        }

        synchronized (stringPool) {
            return stringPool.getOrAddString(val);
        }
    }

    public static Date getDate(long val) {

        synchronized (datePool) {
            return datePool.getOrAddDate(val);
        }
    }

    public static BigDecimal getBigDecimal(BigDecimal val) {

        if (val == null) {
            return val;
        }

        synchronized (bigdecimalPool) {
            return (BigDecimal) bigdecimalPool.getOrAddObject(val);
        }
    }

    public static Boolean getBoolean(boolean b) {
        return b ? Boolean.TRUE
                 : Boolean.FALSE;
    }
}

Other HSQLDB examples (source code examples)

Here is a short list of links related to this HSQLDB ValuePool.java source code file:

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