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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2013, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala
package collection
package mutable
/** `History[A, B]` objects may subscribe to events of
* type `A` published by an object of type `B`.
* The history subscriber object records all published events
* up to maximum number of `maxHistory` events.
*
* @author Matthias Zenger
* @version 1.0, 08/07/2003
* @since 1
*
* @tparam Evt Type of events.
* @tparam Pub Type of publishers.
*/
@SerialVersionUID(5219213543849892588L)
class History[Evt, Pub]
extends AbstractIterable[(Pub, Evt)]
with Subscriber[Evt, Pub]
with Iterable[(Pub, Evt)]
with Serializable
{
protected val log: Queue[(Pub, Evt)] = new Queue
val maxHistory: Int = 1000
/** Notifies this listener with an event by enqueuing it in the log.
*
* @param pub the publisher.
* @param event the event.
*/
def notify(pub: Pub, event: Evt) {
if (log.length >= maxHistory)
log.dequeue()
log.enqueue((pub, event))
}
override def size: Int = log.length
def iterator: Iterator[(Pub, Evt)] = log.iterator
def events: Iterator[Evt] = log.iterator map (_._2)
def clear() { log.clear() }
/** Checks if two history objects are structurally identical.
*
* @return true, iff both history objects contain the same sequence of elements.
*/
override def equals(obj: Any): Boolean = obj match {
case that: History[_, _] => this.log equals that.log
case _ => false
}
override def hashCode = log.hashCode()
}
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