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Constrains the number of concurrently mounted archive file systems in order to save some heap space. This module provides a JMX interface for monitoring and management. Add the JAR artifact of this module to the run time class path to make its services available for service location in the client API modules.

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/*
 * Copyright (C) 2005-2015 Schlichtherle IT Services.
 * All rights reserved. Use is subject to license terms.
 */
package net.java.truevfs.ext

import net.java.truecommons.shed.{BitField, Filter, Visitor}
import net.java.truevfs.kernel.spec.{FsAccessOption, FsController, FsSyncException}

/** Constrains the number of concurrently mounted archive file systems in order
  * to save some heap space.
  * This package provides a JMX interface for monitoring and management.
  *
  * @author Christian Schlichtherle
  */
package object pacemaker {

  type AccessOptions = BitField[FsAccessOption]
  type ControllerFilter = Filter[_ >: FsController]
  type ControllerVisitor = Visitor[_ >: FsController, FsSyncException]

  /** The name of the system property which determines the initial maximum
    * number of mounted archive file systems.
    */
  val maximumFileSystemsMountedPropertyKey =
    classOf[PaceManagerMXBean].getPackage.getName + ".maximumFileSystemsMounted"

  /** The minimum value for the maximum number of mounted archive file systems.
    * This value must not be less than two or otherwise you couldn't even copy
    * entries from one archive file to another.
    * Well, actually you could because the pace manager doesn't unmount archive
    * file systems with open streams or channels, but let's play it safe and
    * pretend it would.
    */
  val maximumFileSystemsMountedMinimumValue = 2

  /** The default value of the system property which determines the initial
    * maximum number of mounted archive file systems.
    * for the maximum number of mounted file systems.
    * The value of this constant will be set to
    * `maximumFileSystemsMountedMinimumValue` unless a system
    * property with the key string
    * `maximumFileSystemsMountedPropertyKey`
    * is set to a value which is greater than
    * `maximumFileSystemsMountedMinimumValue`.
    */
  val maximumFileSystemsMountedDefaultValue =
    math.max(maximumFileSystemsMountedMinimumValue,
      Integer getInteger (maximumFileSystemsMountedPropertyKey,
        maximumFileSystemsMountedMinimumValue))
}