org.apache.river.landlord

Class FixedLeasePeriodPolicy

java.lang.Object

org.apache.river.landlord.FixedLeasePeriodPolicy

All Implemented Interfaces:

LeasePeriodPolicy

public class FixedLeasePeriodPolicy
extends Object
implements LeasePeriodPolicy

Simple implementation of LeasePeriodPolicy that grants lease times based on a fixed default and maximum lease. Will grant renewals longer than the maximum if the current lease and the request are both longer than the maximum.

Since:

2.0

Author:

Sun Microsystems, Inc.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.river.landlord.LeasePeriodPolicy

LeasePeriodPolicy.Result

Constructor Summary

Constructors

Constructor and Description
FixedLeasePeriodPolicy(long maximum, long defaultLength) Create a new FixedLeasePeriodPolicy with the specified values for the maxium and default lease lengths.

Method Summary

Modifier and Type	Method and Description
protected long	calculateDuration(LeasedResource resource, long requestedDuration) Returns the duration this policy is willing to grant for the passed resource at this time.
protected long	currentTime() Method that provides some notion of the current time in milliseconds since the beginning of the epoch.
LeasePeriodPolicy.Result	grant(LeasedResource resource, long requestedDuration) Calculate the initial expiration and duration for a new lease.
LeasePeriodPolicy.Result	renew(LeasedResource resource, long requestedDuration) Calculate the expiration and duration for an existing lease that is being renewed.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FixedLeasePeriodPolicy

public FixedLeasePeriodPolicy(long maximum,
                              long defaultLength)

Create a new FixedLeasePeriodPolicy with the specified values for the maxium and default lease lengths.

Parameters:

maximum - the length in milliseconds of the longest lease this object should normally grant

defaultLength - the length in milliseconds of the default lease grants

Throws:

IllegalArgumentException - if either argument is not positive.

Method Detail

calculateDuration

protected long calculateDuration(LeasedResource resource,
                                 long requestedDuration)

Returns the duration this policy is willing to grant for the passed resource at this time. The duration actually granted will be shorter if the duration extends pass the end of the epoch. Must return a positive number.

Note the duration returned by this method will be shorter than the final duration granted if the requested duration extends past the current expiration, and duration return by this method is before the current expiration.

Parameters:

resource - the resource having a lease granted or renewed

requestedDuration - the duration the client wants

Returns:

duration in milliseconds.

Throws:

IllegalArgumentException - thrown if requestedDuration is less than 0 and not equal to Lease.ANYLENGTH or Lease.FOREVER.

currentTime

protected long currentTime()

Method that provides some notion of the current time in milliseconds since the beginning of the epoch. Default implementation calls System.currentTimeMillis()

Returns:

current time in milliseconds.

grant

public LeasePeriodPolicy.Result grant(LeasedResource resource,
                                      long requestedDuration)
                               throws LeaseDeniedException

Description copied from interface: LeasePeriodPolicy

Calculate the initial expiration and duration for a new lease.

Specified by:

grant in interface LeasePeriodPolicy

Parameters:

resource - the server side representation of the new lease that needs an initial expiration and duration

requestedDuration - the initial duration the requester of the resources would like. May be Lease.ANY

Returns:

A Result that holds both the expiration and duration.

Throws:

LeaseDeniedException - if the grant request is denied.

renew

public LeasePeriodPolicy.Result renew(LeasedResource resource,
                                      long requestedDuration)
                               throws LeaseDeniedException

Description copied from interface: LeasePeriodPolicy

Calculate the expiration and duration for an existing lease that is being renewed.

Specified by:

renew in interface LeasePeriodPolicy

Parameters:

resource - the server side representation of the lease that is being renewed

requestedDuration - the duration the client is requesting. May be Lease.ANY.

Returns:

A Result that holds both the expiration and duration.

Throws:

LeaseDeniedException - if the renewal request is denied.