cassandra-trunk/src/java/org/apache/cassandra/utils/memory/HeapPool.java
/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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.apache.cassandra.utils.memory;

import java.nio.ByteBuffer;

import com.google.common.annotations.VisibleForTesting;

import org.apache.cassandra.utils.Shared;
import org.apache.cassandra.utils.concurrent.OpOrder;

import static org.apache.cassandra.utils.Shared.Scope.SIMULATION;


public class HeapPool extends MemtablePool
{
    public HeapPool(long maxOnHeapMemory, float cleanupThreshold, MemtableCleaner cleaner)
    {
        super(maxOnHeapMemory, 0, cleanupThreshold, cleaner);
    }

    public MemtableAllocator newAllocator(String table)
    {
        return new Allocator(this);
    }

    @VisibleForTesting
    public static class Allocator extends MemtableBufferAllocator
    {
        @VisibleForTesting
        public Allocator(HeapPool pool)
        {
            super(pool.onHeap.newAllocator(), pool.offHeap.newAllocator());
        }

        public ByteBuffer allocate(int size, OpOrder.Group opGroup)
        {
            super.onHeap().allocate(size, opGroup);
            return ByteBuffer.allocate(size);
        }

        public EnsureOnHeap ensureOnHeap()
        {
            return EnsureOnHeap.NOOP;
        }

        public Cloner cloner(OpOrder.Group opGroup)
        {
            return allocator(opGroup);
        }
    }

    public static class Logged extends MemtablePool
    {
        @Shared(scope = SIMULATION)
        public interface Listener
        {
            public void accept(long size, String table);
        }

        private static Listener onAllocated = (i, table) -> {};

        class LoggedSubPool extends SubPool
        {
            public LoggedSubPool(long limit, float cleanThreshold)
            {
                super(limit, cleanThreshold);
            }

            public MemtableAllocator.SubAllocator newAllocator(String table)
            {
                return new MemtableAllocator.SubAllocator(this)
                {
                    public void allocate(long size, OpOrder.Group opGroup)
                    {
                        onAllocated.accept(size, table);
                        super.allocate(size, opGroup);
                    }
                };
            }
        }

        public Logged(long maxOnHeapMemory, float cleanupThreshold, MemtableCleaner cleaner)
        {
            super(maxOnHeapMemory, 0, cleanupThreshold, cleaner);
        }

        public MemtableAllocator newAllocator(String table)
        {
            return new Allocator(this, table);
        }

        private static class Allocator extends MemtableBufferAllocator
        {
            Allocator(Logged pool, String table)
            {
                super(((LoggedSubPool) pool.onHeap).newAllocator(table), ((LoggedSubPool) pool.offHeap).newAllocator(table));
            }

            public ByteBuffer allocate(int size, OpOrder.Group opGroup)
            {
                super.onHeap().allocate(size, opGroup);
                return ByteBuffer.allocate(size);
            }

            @Override
            public EnsureOnHeap ensureOnHeap()
            {
                return EnsureOnHeap.NOOP;
            }

            public Cloner cloner(OpOrder.Group opGroup)
            {
                return allocator(opGroup);
            }
        }

        SubPool getSubPool(long limit, float cleanThreshold)
        {
            return new LoggedSubPool(limit, cleanThreshold);
        }

        public static void setListener(Listener listener)
        {
            onAllocated = listener;
        }
    }
}
