org.springframework.xd.dirt.cluster

Class DefaultContainerMatcher

java.lang.Object

org.springframework.xd.dirt.cluster.DefaultContainerMatcher

All Implemented Interfaces:

ContainerMatcher

public class DefaultContainerMatcher
extends java.lang.Object
implements ContainerMatcher

Implementation of ContainerMatcher that returns a collection of containers to deploy a ModuleDescriptor to. This implementation examines the deployment properties for a stream to determine the preferences for each individual module. The deployment properties can (optionally) specify two preferences: criteria and count.

The criteria indicates that a module should only be deployed to a container for which the criteria evaluates to true. The criteria value should be a valid SpEL expression. If a criteria value is not provided, any container can deploy the module.

If a count for a module is not specified, by default one instance of that module will be deployed to one container. A count of 0 indicates that all containers for which the criteria evaluates to true should deploy the module. If no criteria expression is specified, all containers will deploy the module.

In cases where all containers are not deploying a module, an attempt at container round robin distribution for module deployments will be made (but not guaranteed).

Author:

Patrick Peralta, Mark Fisher, David Turanski, Ilayaperumal Gopinathan

Constructor Summary

Constructors

Constructor and Description
DefaultContainerMatcher() Creates a container matcher instance and prepares the SpEL evaluation context to support Map properties directly.

Method Summary

Methods

Modifier and Type	Method and Description
java.util.Collection<Container>	match(ModuleDescriptor moduleDescriptor, ModuleDeploymentProperties deploymentProperties, java.lang.Iterable<Container> containers) Matches the provided module against one of the candidate containers.

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultContainerMatcher

public DefaultContainerMatcher()

Creates a container matcher instance and prepares the SpEL evaluation context to support Map properties directly.

Method Detail

match

public java.util.Collection<Container> match(ModuleDescriptor moduleDescriptor,
                                    ModuleDeploymentProperties deploymentProperties,
                                    java.lang.Iterable<Container> containers)

Matches the provided module against one of the candidate containers.

Specified by:

match in interface ContainerMatcher

Parameters:

moduleDescriptor - the module to match against

deploymentProperties - deployment properties for the module; this provides hints such as the number of containers and other matching criteria

containers - iterable list of containers to match against

Returns:

a collection of matched containers; collection is empty if no suitable containers are found