com.elastisys.scale.cloudadapters.splitter.cloudadapter

Class SplitterCloudAdapter

java.lang.Object

com.elastisys.scale.cloudadapters.splitter.cloudadapter.SplitterCloudAdapter

All Implemented Interfaces:

CloudAdapter

public class SplitterCloudAdapter
extends Object
implements CloudAdapter

A cloud adapter that splits up the MachinePool to a number of configured CloudAdapters. It communicates with the underlying CloudAdapters via their REST protocol endpoints.

Cloud adapters are prioritized by a number in [0, 100]. The sums of these priorities must equal 100, to ensure that we have an unambiguous configuration. The splitter adapter will instruct its underlying adapters to obtain the correct number of instances based on the priorities (in case of a tie, e.g., two adapters each configured to handle 50% of the machine demand, the first in the configuration file will win).

This class is thread-safe. It guards its modification methods, configure(JsonObject) and resizeMachinePool(int) with its own intrinsic lock. It delegates thread-safety to thread-safe members for getConfiguration(), getConfigurationSchema(), and getMachinePool().

Constructor Summary

Constructors

Constructor and Description
SplitterCloudAdapter() Creates a new instance in an unconfigured state.
SplitterCloudAdapter(Class<? extends PrioritizedRemoteCloudAdapter> adapterClass) Creates a new instance in an unconfigured state, with the ability to specify the implementation class of the remote cloud adapter (useful for testing).

Method Summary

Methods

Modifier and Type	Method and Description
void	configure(com.google.gson.JsonObject configuration) This method is thread-safe, guarded by the class' intrinsic lock for the actual update part of the code, making changes to the configuration appear to be atomic.
com.google.common.base.Optional<com.google.gson.JsonObject>	getConfiguration() This method is thread-safe by delegation to an AtomicReference.
com.google.common.base.Optional<com.google.gson.JsonObject>	getConfigurationSchema() This method is thread-safe by delegation (uses only a private final static constant).
MachinePool	getMachinePool() Queries all configured adapters and summarizes the results.
void	resizeMachinePool(int desiredSize) This method is made thread-safe by guarding it with the class' intrinsic lock.

Methods inherited from class java.lang.Object

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

Constructor Detail

SplitterCloudAdapter

public SplitterCloudAdapter()

Creates a new instance in an unconfigured state.

SplitterCloudAdapter

public SplitterCloudAdapter(Class<? extends PrioritizedRemoteCloudAdapter> adapterClass)

Creates a new instance in an unconfigured state, with the ability to specify the implementation class of the remote cloud adapter (useful for testing).

Parameters:

adapterClass - The class from which remote cloud adapters will be instantiated.

Method Detail

getConfigurationSchema

public com.google.common.base.Optional<com.google.gson.JsonObject> getConfigurationSchema()

This method is thread-safe by delegation (uses only a private final static constant).

Specified by:

getConfigurationSchema in interface CloudAdapter

configure

public void configure(com.google.gson.JsonObject configuration)
               throws IllegalArgumentException,
                      CloudAdapterException

This method is thread-safe, guarded by the class' intrinsic lock for the actual update part of the code, making changes to the configuration appear to be atomic.

Specified by:

configure in interface CloudAdapter

Throws:

IllegalArgumentException

CloudAdapterException

getConfiguration

public com.google.common.base.Optional<com.google.gson.JsonObject> getConfiguration()

This method is thread-safe by delegation to an AtomicReference.

Specified by:

getConfiguration in interface CloudAdapter

getMachinePool

public MachinePool getMachinePool()
                           throws CloudAdapterException

Queries all configured adapters and summarizes the results. This method is thread-safe by delegation to AtomicReference.

Specified by:

getMachinePool in interface CloudAdapter

Throws:

CloudAdapterException

resizeMachinePool

public void resizeMachinePool(int desiredSize)
                       throws IllegalArgumentException,
                              CloudAdapterException

This method is made thread-safe by guarding it with the class' intrinsic lock.

Specified by:

resizeMachinePool in interface CloudAdapter

Throws:

IllegalArgumentException

CloudAdapterException