HSQLDB example source code file (ObjectCacheHashMap.java)

This example HSQLDB source code file (ObjectCacheHashMap.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

basehashiterator, basehashmap, basehashmap, collection, illegalargumentexception, iterator, object, object, objectcachehashmap, objectcachehashmap, objectcacheiterator, objectcacheiterator, set

The HSQLDB ObjectCacheHashMap.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 org.hsqldb.lib.Collection;
import org.hsqldb.lib.Iterator;
import org.hsqldb.lib.Set;

/**
 * Maps integer keys to Objects. Hashes the keys.
 *
 * @author fredt@users
 * @version 1.8.0
 * @since 1.8.0
 */
public class ObjectCacheHashMap extends BaseHashMap {

    Set        keySet;
    Collection values;

    public ObjectCacheHashMap(int initialCapacity)
    throws IllegalArgumentException {
        super(initialCapacity, 1, BaseHashMap.intKeyOrValue,
              BaseHashMap.objectKeyOrValue, true);
    }

    public Object get(int key) {

        if (accessCount == Integer.MAX_VALUE) {
            resetAccessCount();
        }

        int lookup = getLookup(key);

        if (lookup == -1) {
            return null;
        }

        accessTable[lookup] = accessCount++;

        return objectValueTable[lookup];
    }

    public Object put(int key, Object value) {

        if (accessCount == Integer.MAX_VALUE) {
            resetAccessCount();
        }

        return super.addOrRemove(key, value, false);
    }

    public Object remove(int key) {
        return super.addOrRemove(key, null, true);
    }

    /**
     * for count number of elements with the given margin, return the access
     * count.
     */
    public int getAccessCountCeiling(int count, int margin) {
        return super.getAccessCountCeiling(count, margin);
    }

    /**
     * This is called after all elements below count accessCount have been
     * removed
     */
    public void setAccessCountFloor(int count) {
        super.accessMin = count;
    }

    public ObjectCacheIterator iterator() {
        return new ObjectCacheIterator();
    }

    public class ObjectCacheIterator extends BaseHashIterator
    implements Iterator {}
}