ObjectArrayPool.java

//--------------------------------------------------------------------------
//	Copyright (c) 1998-2004, Drew Davidson and Luke Blanshard
//  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 Drew Davidson 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 THE
//  COPYRIGHT OWNER 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 ariba.util.expr;

import java.util.*;

public final class ObjectArrayPool extends Object
{
    private IntHashMap      pools = new IntHashMap(23);

    public static class SizePool extends Object
    {
        private List        arrays = new ArrayList();
        private int         arraySize;
        private int         size;
        private int         created = 0;
        private int         recovered = 0;
        private int         recycled = 0;

        public SizePool(int arraySize)
        {
            this(arraySize, 0);
        }

        public SizePool(int arraySize, int initialSize)
        {
            super();
            this.arraySize = arraySize;
            for (int i = 0; i < initialSize; i++) {
                arrays.add(new Object[arraySize]);
            }
            created = size = initialSize;
        }

        public int getArraySize()
        {
            return arraySize;
        }

        public Object[] create()
        {
            Object[]        result;

            if (size > 0) {
                result = (Object[])arrays.remove(size - 1);
                size--;
                recovered++;
            } else {
                result = new Object[arraySize];
                created++;
            }
            return result;
        }

        public synchronized void recycle(Object[] value)
        {
            if (value != null) {
                if (value.length != arraySize) {
                    throw new IllegalArgumentException("recycled array size " + value.length + " inappropriate for pool array size " + arraySize);
                }
                Arrays.fill(value, null);
                arrays.add(value);
                size++;
                recycled++;
            } else {
                throw new IllegalArgumentException("cannot recycle null object");
            }
        }

        /**
            Returns the number of items in the pool
         */
        public int getSize()
        {
            return size;
        }

        /**
            Returns the number of items this pool has created since
            it's construction.
         */
        public int getCreatedCount()
        {
            return created;
        }

        /**
            Returns the number of items this pool has recovered from
            the pool since its construction.
         */
        public int getRecoveredCount()
        {
            return recovered;
        }

        /**
            Returns the number of items this pool has recycled since
            it's construction.
         */
        public int getRecycledCount()
        {
            return recycled;
        }
    }

    public ObjectArrayPool()
    {
        super();
    }

    public IntHashMap getSizePools()
    {
        return pools;
    }

    public synchronized SizePool getSizePool(int arraySize)
    {
        SizePool     result = (SizePool)pools.get(arraySize);

        if (result == null) {
            pools.put(arraySize, result = new SizePool(arraySize));
        }
        return result;
    }

    public synchronized Object[] create(int arraySize)
    {
        return getSizePool(arraySize).create();
    }

    public synchronized Object[] create(Object singleton)
    {
        Object[]        result = create(1);

        result[0] = singleton;
        return result;
    }

    public synchronized Object[] create(Object object1, Object object2)
    {
        Object[]        result = create(2);

        result[0] = object1;
        result[1] = object2;
        return result;
    }

    public synchronized Object[] create(Object object1, Object object2, Object object3)
    {
        Object[]        result = create(3);

        result[0] = object1;
        result[1] = object2;
        result[2] = object3;
        return result;
    }

    public synchronized Object[] create(Object object1, Object object2, Object object3, Object object4)
    {
        Object[]        result = create(4);

        result[0] = object1;
        result[1] = object2;
        result[2] = object3;
        result[3] = object4;
        return result;
    }

    public synchronized Object[] create(Object object1, Object object2, Object object3, Object object4, Object object5)
    {
        Object[]        result = create(5);

        result[0] = object1;
        result[1] = object2;
        result[2] = object3;
        result[3] = object4;
        result[4] = object5;
        return result;
    }

    public synchronized void recycle(Object[] value)
    {
        if (value != null) {
            getSizePool(value.length).recycle(value);
        }
    }
}