/*
 * 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.hyracks.storage.common.buffercache;

import java.nio.ByteBuffer;

import org.apache.hyracks.api.exceptions.HyracksDataException;
import org.apache.hyracks.storage.common.IResourceMemoryManager;

public class ResourceHeapBufferAllocator implements ICacheMemoryAllocator {

    final IResourceMemoryManager memoryManager;
    final String resourceName;

    public ResourceHeapBufferAllocator(IResourceMemoryManager memoryManager, String resourceName) {
        this.memoryManager = memoryManager;
        this.resourceName = resourceName;
    }

    @Override
    public ByteBuffer[] allocate(int pageSize, int numPages) {
        ByteBuffer[] buffers = new ByteBuffer[numPages];
        for (int i = 0; i < numPages; ++i) {
            buffers[i] = ByteBuffer.allocate(pageSize);
        }
        return buffers;
    }

    @Override
    public ByteBuffer[] ensureAvailabilityThenAllocate(int pageSize, int numPages) throws HyracksDataException {
        reserveAllocation(pageSize, numPages);
        return allocate(pageSize, numPages);
    }

    @Override
    public void reserveAllocation(int pageSize, int numPages) throws HyracksDataException {
        memoryManager.allocateMemory(resourceName);
    }
}
