code: /**
   * Copyright (c) 2007, Regents of the University of California
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * Redistributions of source code must retain the above copyright notice,
   * this list of conditions and the following disclaimer.
   *
   * Redistributions in binary form must reproduce the above copyright
   * notice, this list of conditions and the following disclaimer in the
   * documentation and/or other materials provided with the distribution.
   *
   * Neither the name of the University of California, Los Angeles nor the
   * names of its contributors may be used to endorse or promote products
   * derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * Created Oct 20, 2007
   */
  package avrora.sim.output;
  
  import avrora.sim.Simulator;
  
  /**
   * The <code>EventBuffer</code> definition.
   *
   * @author Ben L. Titzer
   */
  public class EventBuffer {
  
      public class Event {
          public final long time;
          public final Object object;
          public final long param;
          public Event next;
  
          Event(Object object, long param) {
              this.time = sim.getClock().getCount();
              this.object = object;
              this.param = param;
          }
  
          public Simulator getSimulator() {
              return sim;
          }
      }
  
      public final Simulator sim;
      protected Event head;
      protected Event tail;
  
      public EventBuffer(Simulator s) {
          sim = s;
      }
  
      protected Event recordEvent(Object o, long param) {
          Event e = new Event(o, param);
          if (tail == null) {
              head = tail = e;
          } else {
              tail.next = e;
              tail = e;
          }
          return e;
      }
  
      public Event extract(long time) {
          Event prev = null;
          Event cur = head;
          while (cur != null) {
              if (cur.time >= time) {
                  // chop the list before this node
                  if (prev != null) {
                      // extracted at least one node
                      prev.next = null;
                      prev = head;
                      head = cur;
                      return prev;
                  }
                  // did not extract any nodes
                  return null;
              }
              prev = cur;
              cur = cur.next;
          }
          // consumed the whole list
          cur = head;
          head = tail = null;
          return cur;
      }
  }
  