com.budjb.spring.distributed.cluster

Interface ClusterManager

All Known Implementing Classes:

AbstractClusterManager, StandaloneClusterManager

public interface ClusterManager

Describes a class that allows interaction with other running application nodes that are considered clustered. This functionality serves to help synchronize state between application nodes so that meaningful and stateful load balancing may occur.

Method Summary

Modifier and Type	Method and Description
java.util.List<ClusterMember>	getClusterMembers() Returns the set of cluster members that will share workloads.
java.lang.String	getProperty(java.lang.String name) Retrieves a distributed property.
<T> T	getProperty(java.lang.String name, java.lang.Class<T> clazz) Retrieves a distributed property.
<T> T	getProperty(java.lang.String name, java.lang.Class<T> clazz, T defaultValue) Retrieves a distributed property.
void	setProperty(java.lang.String name, java.lang.Object value) Sets a distributed property and syncs it with all cluster members.
<T> java.util.Map<ClusterMember,T>	submitInstruction(Instruction<? extends T> instruction) Submits an instruction to all cluster members.
<T> java.util.Map<ClusterMember,? extends T>	submitInstructions(java.util.Map<ClusterMember,? extends Instruction<? extends T>> instructions) Submits instructions to members of the cluster.

Method Detail

getClusterMembers

java.util.List<ClusterMember> getClusterMembers()

Returns the set of cluster members that will share workloads.

Returns:

the set of cluster members that will share workloads.

getProperty

java.lang.String getProperty(java.lang.String name)

Retrieves a distributed property.

Note that just as with accessing shared state between threads, access to properties should be synchronized across all cluster members through some sort of locking mechanism.

Parameters:

name - Name of the property.

Returns:

The value of the property, or null if it is not set.

getProperty

<T> T getProperty(java.lang.String name,
                  java.lang.Class<T> clazz)

Retrieves a distributed property.

The value of the property, if it exists, must be of the requested type. If it does not exist, or the value does match the type, null is returned.

Note that just as with accessing shared state between threads, access to properties should be synchronized across all cluster members through some sort of locking mechanism.

Type Parameters:

T - Requested value type.

Parameters:

name - Name of the property.

clazz - Required class type of the property.

Returns:

The value of the property, or null if it is not set or is not of the correct type.

getProperty

<T> T getProperty(java.lang.String name,
                  java.lang.Class<T> clazz,
                  T defaultValue)

Retrieves a distributed property.

The value of the property, if it exists, must be of the requested type. If it does not exist, or the value does match the type, the default value is returned.

Note that just as with accessing shared state between threads, access to properties should be synchronized across all cluster members through some sort of locking mechanism.

Type Parameters:

T - Requested value type.

Parameters:

name - Name of the property.

clazz - Required class type of the property.

defaultValue - Default value to return if the property isn't set or is of the wrong type.

Returns:

The value of the property, or the default value if it is not set or is not of the correct type.

setProperty

void setProperty(java.lang.String name,
                 java.lang.Object value)

Sets a distributed property and syncs it with all cluster members.

Note that just as with accessing shared state between threads, access to properties should be synchronized across all cluster members through some sort of locking mechanism.

Parameters:

name - Name of the property.

value - Value of the property.

submitInstructions

<T> java.util.Map<ClusterMember,? extends T> submitInstructions(java.util.Map<ClusterMember,? extends Instruction<? extends T>> instructions)
                                                         throws java.util.concurrent.ExecutionException,
                                                                java.lang.InterruptedException

Submits instructions to members of the cluster.

Type Parameters:

T - The return type of the instruction.

Parameters:

instructions - instructions to run on cluster members.

Returns:

the results of the instructions, mapped to the member that generated them.

Throws:

java.util.concurrent.ExecutionException - when an error during execution occurs.

java.lang.InterruptedException - when the processes is interrupted.

submitInstruction

<T> java.util.Map<ClusterMember,T> submitInstruction(Instruction<? extends T> instruction)
                                              throws java.util.concurrent.ExecutionException,
                                                     java.lang.InterruptedException

Submits an instruction to all cluster members.

Type Parameters:

T - The return type of the instruction.

Parameters:

instruction - instructions to run on all cluster members.

Returns:

the results of the instructions, mapped to the member that generated them.

Throws:

java.util.concurrent.ExecutionException - when an error during execution occurs.

java.lang.InterruptedException - when the processes is interrupted.