modules/gemfire-modules-session/src/main/java/com/gemstone/gemfire/modules/session/filter/attributes/DeltaQueuedSessionAttributes.java

/*=========================================================================
 * Copyright (c) 2010-2014 Pivotal Software, Inc. All Rights Reserved.
 * This product is protected by U.S. and international copyright
 * and intellectual property laws. Pivotal products are covered by
 * one or more patents listed at http://www.pivotal.io/patents.
 *=========================================================================
 */
package com.gemstone.gemfire.modules.session.filter.attributes;

import com.gemstone.gemfire.DataSerializable;
import com.gemstone.gemfire.Instantiator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * This class implements delayed attribute delta propagation. Updates to
 * attributes are only propagated once the session goes out of scope - i.e. as
 * the request is done being processed.
 */
public class DeltaQueuedSessionAttributes extends AbstractDeltaSessionAttributes {

  private static final Logger LOG =
      LoggerFactory.getLogger(DeltaQueuedSessionAttributes.class.getName());

  private Trigger trigger = Trigger.SET;

  private enum Trigger {
    SET,
    SET_AND_GET;
  }

  /**
   * Register ourselves for de-serialization
   */
  static {
    Instantiator.register(
        new Instantiator(DeltaQueuedSessionAttributes.class, 3479) {
          @Override
          public DataSerializable newInstance() {
            return new DeltaQueuedSessionAttributes();
          }
        });
  }

  /**
   * Default constructor
   */
  public DeltaQueuedSessionAttributes() {
  }

  public void setReplicationTrigger(String trigger) {
    this.trigger = Trigger.valueOf(trigger.toUpperCase());
  }

  @Override
  public Object getAttribute(String attr) {
    if (trigger == Trigger.SET_AND_GET) {
      deltas.put(attr, new DeltaEvent(session, attr));
    }
    return super.getAttribute(attr);
  }

  /**
   * {@inheritDoc} Put an attribute, setting the dirty flag. The changes are
   * flushed at the end of filter processing.
   */
  @Override
  public Object putAttribute(String attr, Object value) {
    Object obj = attributes.put(attr, value);
    deltas.put(attr, new DeltaEvent(true, attr, value));
    return obj;
  }

  /**
   * {@inheritDoc} Remove an attribute, setting the dirty flag. The changes are
   * flushed at the end of filter processing.
   */
  @Override
  public Object removeAttribute(String attr) {
    Object obj = attributes.remove(attr);
    deltas.put(attr, new DeltaEvent(false, attr, null));
    return obj;
  }
}