/**
    * This file Copyright (c) 2013-2015 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.module.cache.filter;
  
  import info.magnolia.context.MgnlContext;
  
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.io.OutputStream;
  
  import javax.servlet.http.HttpServletRequest;
  
  import org.apache.commons.io.output.ThresholdingOutputStream;
  
  /**
   * Output stream that will trigger an event when threshold reached.
   */
  abstract class AbstractThresholdingCacheOutputStream extends ThresholdingOutputStream {
  
      private final HttpServletRequest request;
      protected OutputStream out;
  
      private boolean thresholdExceeded;
      private int written;
  
      public AbstractThresholdingCacheOutputStream(int threshold) {
          super(threshold);
          this.out = new ByteArrayOutputStream();
          if (MgnlContext.isWebContext()) {
              request = MgnlContext.getWebContext().getRequest();
          } else {
              request = null;
          }
      }
  
      @Override
      protected OutputStream getStream() throws IOException {
          return getInMemoryBuffer();
      }
  
      @Override
      protected abstract void thresholdReached() throws IOException;
  
      public OutputStream getInMemoryBuffer() {
          return out;
      }
  
      @Override
      public void write(int b) throws IOException {
          checkThreshold(1);
          getStream().write(b);
          written++;
      }
  
      @Override
      public void write(byte b[]) throws IOException {
          checkThreshold(b.length);
          getStream().write(b);
          written += b.length;
      }
  
      @Override
      public void write(byte b[], int off, int len) throws IOException {
          checkThreshold(len);
          getStream().write(b, off, len);
          written += len;
      }
  
     @Override
     public long getByteCount() {
         return written;
     }
 
     @Override
     public boolean isThresholdExceeded() {
         return written > this.getThreshold();
     }
 
     @Override
     protected void checkThreshold(int count) throws IOException {
         if (!thresholdExceeded && written + count > this.getThreshold()) {
             thresholdExceeded = true;
             thresholdReached();
         }
     }
 
     @Override
     public int getThreshold() {
         if (request != null) {
             Integer threshold = (Integer) request.getAttribute(CacheResponseWrapper.ATTRIBUTE_IN_MEMORY_THRESHOLD);
             if (threshold != null) {
                 return threshold;
             }
         }
         return super.getThreshold();
     }
 
     @Override
     protected void resetByteCount() {
         this.thresholdExceeded = false;
         this.written = 0;
     }
 
 }