org.apache.sling.discovery.base.commons

Class DefaultTopologyView

java.lang.Object

org.apache.sling.discovery.commons.providers.BaseTopologyView

org.apache.sling.discovery.base.commons.DefaultTopologyView

All Implemented Interfaces:

TopologyView

public class DefaultTopologyView
extends BaseTopologyView

Default Implementation of the topology view interface

Constructor Summary

Constructors

Constructor and Description
DefaultTopologyView() Create a new empty topology
DefaultTopologyView(Collection<InstanceDescription> instances) Create a new topology filled with the given list of instances

Method Summary

Modifier and Type	Method and Description
void	addInstances(Collection<InstanceDescription> instances) Adds the given instances to this topology
TopologyEvent.Type	compareTopology(DefaultTopologyView other) Compare this topology with the given one and determine how they compare
boolean	equals(Object obj)
Set<InstanceDescription>	findInstances(InstanceFilter picker) Searches through this topology and picks those accepted by the provided InstanceFilter - and returns them without any particular order
Set<ClusterView>	getClusterViews() Provides the collection of ClusterViews.
Set<InstanceDescription>	getInstances() Provides the set of InstanceDescriptions in the entire topology, without any particular order
String	getLocalClusterSyncTokenId() Returns the id that shall be used in the syncToken by the ClusterSyncService.
InstanceDescription	getLocalInstance() Provides the InstanceDescription belonging to this instance.
int	hashCode()
void	setLocalClusterView(LocalClusterView localClusterView) Adds the instances of the given ClusterView to this topology
String	toString()

Methods inherited from class org.apache.sling.discovery.commons.providers.BaseTopologyView

getInstance, isCurrent, setNotCurrent, toShortString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

DefaultTopologyView

public DefaultTopologyView()

Create a new empty topology

DefaultTopologyView

public DefaultTopologyView(Collection<InstanceDescription> instances)

Create a new topology filled with the given list of instances

Method Detail

compareTopology

public TopologyEvent.Type compareTopology(DefaultTopologyView other)

Compare this topology with the given one and determine how they compare

Parameters:

other - the other topology against which to compare

Returns:

the type describing how these two compare

See Also:

TopologyEvent.Type

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

getLocalInstance

public InstanceDescription getLocalInstance()

Description copied from interface: TopologyView

Provides the InstanceDescription belonging to this instance.

Returns:

the InstanceDescription belonging to this instance

See Also:

TopologyView.getLocalInstance()

getInstances

public Set<InstanceDescription> getInstances()

Description copied from interface: TopologyView

Provides the set of InstanceDescriptions in the entire topology, without any particular order

Returns:

the set of InstanceDescriptions in the entire topology, without any particular order

See Also:

TopologyView.getInstances()

setLocalClusterView

public void setLocalClusterView(LocalClusterView localClusterView)

Adds the instances of the given ClusterView to this topology

addInstances

public void addInstances(Collection<InstanceDescription> instances)

Adds the given instances to this topology

findInstances

public Set<InstanceDescription> findInstances(InstanceFilter picker)

Description copied from interface: TopologyView

Searches through this topology and picks those accepted by the provided InstanceFilter - and returns them without any particular order

Parameters:

picker - the filter to use

Returns:

the set of InstanceDescriptions which were accepted by the InstanceFilter, without any particular order

See Also:

TopologyView.findInstances(org.apache.sling.discovery.InstanceFilter)

getClusterViews

public Set<ClusterView> getClusterViews()

Description copied from interface: TopologyView

Provides the collection of ClusterViews.

Note that all InstanceDescriptions belong to exactly one ClusterView - including InstanceDescriptions that form "a cluster of 1"

Returns:

the set of ClusterViews, without any particular order

See Also:

TopologyView.getClusterViews()

toString

public String toString()

Overrides:

toString in class Object

getLocalClusterSyncTokenId

public String getLocalClusterSyncTokenId()

Description copied from class: BaseTopologyView

Returns the id that shall be used in the syncToken by the ClusterSyncService.

The clusterSyncId uniquely identifies each change of the local cluster for all participating instances. That means, all participating instances know of the clusterSyncId and it is the same for all instances. Whenever an instance joins/leaves the cluster, this clusterSyncId must change.

Since this method returns the *local* clusterSyncId, it doesn't care if a remote cluster experienced changes - it must only change when the local cluster changes. However, it *can* change when a remote cluster changes too. So the requirement is just that it changes *at least* when the local cluster changes - but implementations can opt to regard this rather as a TopologyView-ID too (ie an ID that identifies a particular incarnation of the TopologyView for all participating instances in the whole topology).

This id can further safely be used by the ClusterSyncService to identify a syncToken that it writes and that all other instances in the lcoal cluster wait for, before sending a TOPOLOGY_CHANGED event.

Note that this is obviously not to be confused with the ClusterView.getId() which is stable throughout the lifetime of a cluster.

Specified by:

getLocalClusterSyncTokenId in class BaseTopologyView