/*
 * Copyright (c) MuleSoft, Inc.  All rights reserved.  http://www.mulesoft.com
 * The software in this package is published under the terms of the CPAL v1.0
 * license, a copy of which has been included with this distribution in the
 * LICENSE.txt file.
 */
package org.mule.runtime.core.util.compression;

import org.mule.runtime.core.util.ClassUtils;

import java.security.AccessController;
import java.security.PrivilegedAction;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * <code>CompressionHelper</code> a static class that provides facilities for compressing and uncompressing byte arrays
 */

public final class CompressionHelper {

  /**
   * logger used by this class
   */
  private static Logger logger = LoggerFactory.getLogger(CompressionHelper.class);

  private static CompressionStrategy defaultStrategy;

  /** Do not instanciate. */
  private CompressionHelper() {
    // no-op
  }

  public static synchronized CompressionStrategy getDefaultCompressionStrategy() {
    if (defaultStrategy == null) {
      defaultStrategy = AccessController.doPrivileged(new PrivilegedAction<CompressionStrategy>() {

        @Override
        public CompressionStrategy run() {
          try {
            Object o = ClassUtils.loadClass(CompressionStrategy.COMPRESSION_DEFAULT, CompressionHelper.class).newInstance();
            if (logger.isDebugEnabled()) {
              logger.debug("Found CompressionStrategy: " + o.getClass().getName());
            }
            return (CompressionStrategy) o;
          } catch (Exception e) {
            // TODO MULE-863: What should we really do? Document this?
            logger.warn("Failed to build compression strategy: " + e.getMessage());
          }
          return null;
        }
      });
    }
    return defaultStrategy;
  }

}