https://github.com/Terracotta-OSS/offheap-store/: A library that offers data structures allocated off the java heap. 
/* 
 * Copyright 2015 Terracotta, Inc., a Software AG company.
 *
 * Licensed 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.terracotta.offheapstore.paging;


Author:cdennis
/**
 *
 * @author cdennis
 */
public interface PageSource {

  
Attempt to allocate a page of the given size.


Allocations identified as thieves will if necessary 'steal' space from
previous allocations identified as 'victims' in order to fulfill the
allocation request.  owner is the area from which the
returned page can subsequently be stolen or recovered.  This is most likely
to be the calling instance.

Params:
  • size – size of page to allocate
  • thief – true if the allocation can steal space from victims
  • victim – true if the allocated page should be eligible for stealing
  • owner – owner from which subsequent steal should occur
Returns:an allocated page, or null in the case of failure
/**
   * Attempt to allocate a page of the given size.
   * <p>
   * Allocations identified as thieves will if necessary 'steal' space from
   * previous allocations identified as 'victims' in order to fulfill the
   * allocation request.  <code>owner</code> is the area from which the
   * returned page can subsequently be stolen or recovered.  This is most likely
   * to be the calling instance.
   *
   * @param size size of page to allocate
   * @param thief {@code true} if the allocation can steal space from victims
   * @param victim {@code true} if the allocated page should be eligible for stealing
   * @param owner owner from which subsequent steal should occur
   * @return an allocated page, or {@code null} in the case of failure
   */
  Page allocate(int size, boolean thief, boolean victim, OffHeapStorageArea owner);

  void free(Page page);
}