content: /*******************************************************************************
   * Copyright 2014 Trevor Robinson
   * 
   * 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 com.scurrilous.circe.impl;
  
  import java.nio.ByteBuffer;
  import java.util.Iterator;
  import java.util.ServiceLoader;
  
  /**
   * Provides access to a singleton {@link DirectByteBufferAccess} implementation,
   * if one is available.
   */
  public final class DirectByteBufferAccessLoader {
  
      private static final DirectByteBufferAccess INSTANCE;
  
      static {
          final Iterator<DirectByteBufferAccess> iterator = ServiceLoader.load(
                  DirectByteBufferAccess.class).iterator();
          INSTANCE = iterator.hasNext() ? iterator.next() : null;
      }
  
      /**
       * Returns the native memory address of the given direct byte buffer, or 0
       * if the buffer is not direct or if obtaining the address is not supported.
       * 
       * @param buffer the direct byte buffer for which to obtain the address
       * @return the native memory address or 0
       */
      public static long getAddress(ByteBuffer buffer) {
          return INSTANCE != null ? INSTANCE.getAddress(buffer) : 0;
      }
  
      private DirectByteBufferAccessLoader() {
      }
  }
  