Package io.hekate.cluster

Class UpdatableClusterView

java.lang.Object

io.hekate.cluster.UpdatableClusterView

All Implemented Interfaces:

ClusterFilterSupport<ClusterView>, ClusterTopologySupport, ClusterView

public class UpdatableClusterView
extends Object
implements ClusterView

Simple updatable version of the ClusterView interface.

This class represents an updatable version of the ClusterView interface and provides support for manual management of this view's cluster topology via update(ClusterTopology) method. This class can be used for manual testing of cluster-dependent components.

Notice: This class doesn't support neither ClusterEventListeners nor cluster futures. All methods related to this functionality throw UnsupportedOperationExceptions.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	UpdatableClusterView(ClusterTopology topology)	Constructs a new instance.

Method Summary

Modifier and Type	Method	Description
void	addListener(ClusterEventListener listener)	Throws UnsupportedOperationException.
void	addListener(ClusterEventListener listener, ClusterEventType... eventTypes)	Throws UnsupportedOperationException.
boolean	awaitFor(Predicate<ClusterTopology> predicate)	Throws UnsupportedOperationException.
boolean	awaitFor(Predicate<ClusterTopology> predicate, long timeout, TimeUnit timeUnit)	Throws UnsupportedOperationException.
static UpdatableClusterView	empty()	Constructs a new empty cluster view.
ClusterView	filterAll(ClusterFilter filter)	Returns a copy of this instance that will use the specified filter along with all the filter criteria that were inherited from this instance.
CompletableFuture<ClusterTopology>	futureOf(Predicate<ClusterTopology> predicate)	Throws UnsupportedOperationException.
static UpdatableClusterView	of(int version, ClusterNode node)	Constructs a new view.
static UpdatableClusterView	of(int version, Set<ClusterNode> nodes)	Constructs a new view.
static UpdatableClusterView	of(ClusterTopology topology)	Constructs a new view.
void	removeListener(ClusterEventListener listener)	Throws UnsupportedOperationException.
ClusterTopology	topology()	Returns the cluster topology.
<T> T	topologyContext(Function<ClusterTopology,T> supplier)	Constructs a new context object or returns a cached one, based on the current cluster topology.
String	toString()
void	update(ClusterTopology topology)	Updates the cluster topology of this view if the specified topology has higher version than the one that is already assigned to this view.

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.hekate.cluster.ClusterFilterSupport

filter, forNode, forNode, forOldest, forProperty, forProperty, forRemotes, forRole, forService, forYoungest

Methods inherited from interface io.hekate.cluster.ClusterView

awaitForNodes, awaitForNodes, forEach

Constructor Detail

UpdatableClusterView

protected UpdatableClusterView(ClusterTopology topology)

Constructs a new instance.

Parameters:

topology - Topology.

Method Detail

of

public static UpdatableClusterView of(ClusterTopology topology)

Constructs a new view.

Parameters:

topology - Topology.

Returns:

New cluster view.

of

public static UpdatableClusterView of(int version,
                                      ClusterNode node)

Constructs a new view.

Parameters:

version - Topology version (see ClusterTopology.version()).

node - Cluster node.

Returns:

New cluster view.

of

public static UpdatableClusterView of(int version,
                                      Set<ClusterNode> nodes)

Constructs a new view.

Parameters:

version - Topology version (see ClusterTopology.version()).

nodes - Cluster nodes.

Returns:

New cluster view.

empty

public static UpdatableClusterView empty()

Constructs a new empty cluster view.

Returns:

New cluster view.

See Also:

ClusterTopology.empty()

update

public void update(ClusterTopology topology)

Updates the cluster topology of this view if the specified topology has higher version than the one that is already assigned to this view.

Parameters:

topology - New topology.

filterAll

public ClusterView filterAll(ClusterFilter filter)

Description copied from interface: ClusterFilterSupport

Returns a copy of this instance that will use the specified filter along with all the filter criteria that were inherited from this instance.

Notice: for performance reasons it is highly recommended to cache and reuse the filtered instance instead of re-building it over and over again.

// Bad!!! (filtering is performed on every iteration).
for (int i = 0; i < 1000; i++) {
    cluster.forRemotes().forRole("some_role").doSomething();
}

// Good (filtering is performed only once).
filtered = cluster.forRemotes().forRole("some_role");
for (int i = 0; i < 1000; i++) {
    filtered.doSomething();
}

Specified by:

filterAll in interface ClusterFilterSupport<ClusterView>

Parameters:

filter - Filter.

Returns:

Filtered instance.

topology

public ClusterTopology topology()

Description copied from interface: ClusterTopologySupport

Returns the cluster topology.

Specified by:

topology in interface ClusterTopologySupport

Returns:

Cluster topology.

addListener

public void addListener(ClusterEventListener listener)

Throws UnsupportedOperationException.

Specified by:

addListener in interface ClusterView

Parameters:

listener - Listener.

addListener

public void addListener(ClusterEventListener listener,
                        ClusterEventType... eventTypes)

Throws UnsupportedOperationException.

Specified by:

addListener in interface ClusterView

Parameters:

listener - Listener.

eventTypes - Types of cluster events that this listener should be notified on.

removeListener

public void removeListener(ClusterEventListener listener)

Throws UnsupportedOperationException.

Specified by:

removeListener in interface ClusterView

Parameters:

listener - Listener.

topologyContext

public <T> T topologyContext(Function<ClusterTopology,T> supplier)

Description copied from interface: ClusterView

Constructs a new context object or returns a cached one, based on the current cluster topology.

This method provides support to cache user context objects that depend on the current cluster topology and should be reconstructed whenever the cluster topology changes. Such objects are cached at the ClusterView instance level. When topology changes, a new object is constructed via the provided supplier function.

Note that only one context object is supported per ClusterView instance. Any attempt to use different supplier functions will lead to unpredictable results.

Specified by:

topologyContext in interface ClusterView

Type Parameters:

T - Context type.

Parameters:

supplier - Context supplier (must be idempotent and free of side effects).

Returns:

Context object.

futureOf

public CompletableFuture<ClusterTopology> futureOf(Predicate<ClusterTopology> predicate)

Throws UnsupportedOperationException.

Specified by:

futureOf in interface ClusterView

Parameters:

predicate - Topology predicate.

Returns:

Topology future.

awaitFor

public boolean awaitFor(Predicate<ClusterTopology> predicate)

Throws UnsupportedOperationException.

Specified by:

awaitFor in interface ClusterView

Parameters:

predicate - Predicate that gets checked every time when underlying cluster topology is changed.

Returns:

if predicate matched with this cluster view; false in all other cases (thread interruption, node stop, etc).

awaitFor

public boolean awaitFor(Predicate<ClusterTopology> predicate,
                        long timeout,
                        TimeUnit timeUnit)

Throws UnsupportedOperationException.

Specified by:

awaitFor in interface ClusterView

Parameters:

predicate - Predicate that gets checked every time when underlying cluster topology is changed.

timeout - Timeout.

timeUnit - Time unit.

Returns:

if predicate matched with this cluster view; false in all other cases (thread interruption, node stop, etc).

toString

public String toString()

Overrides:

toString in class Object