org.hawkular.inventory.api

Enum Relationships.WellKnown

java.lang.Object

java.lang.Enum<Relationships.WellKnown>

org.hawkular.inventory.api.Relationships.WellKnown

All Implemented Interfaces:

Serializable, Comparable<Relationships.WellKnown>

Enclosing class:

Relationships

public static enum Relationships.WellKnown
extends Enum<Relationships.WellKnown>

The list of well-known relationships (aka edges) between entities (aka vertices).

Enum Constant Summary

Enum Constants

Enum Constant and Description
contains Expresses encapsulation of a set of entities in another entity.
defines Expresses "instantiation" of some entity based on the definition provided by "source" entity.
incorporates Expresses inclusion.
isParentOf Used to express hierarchy of resources.

Method Summary

Modifier and Type	Method and Description
static Relationships.WellKnown	valueOf(String name) Returns the enum constant of this type with the specified name.
static Relationships.WellKnown[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

contains

public static final Relationships.WellKnown contains

Expresses encapsulation of a set of entities in another entity. Used for example to express the relationship between a tenant and the set of its environments.

Note that entities that are contained within another entity (by the virtue of there being this relationship between them) are deleted along with it.

Note also that it is prohibited to create loops in the contains relationships, i.e. an entity cannot (indirectly) contain itself. Also, containment is unique and therefore 1 entity cannot be contained in 2 or more other entities.

defines

public static final Relationships.WellKnown defines

Expresses "instantiation" of some entity based on the definition provided by "source" entity. For example, there is a defines relationship between a metric definition and all metrics that conform to it.

Note that as long as an entity defines other entities, it cannot be deleted.

incorporates

public static final Relationships.WellKnown incorporates

Expresses inclusion. For example a resource incorporates a set of metrics, or a resource type incorporates a set of metric definitions. They do not contain it though, because more resources can incorporate a single metric for example.

isParentOf

public static final Relationships.WellKnown isParentOf

Used to express hierarchy of resources.

There are 2 separate concepts that need to be understood when examining resource hierarchy:

1. The embedding of resources into each other - i.e. the child resources are inseparable from their parent, because they are its parts - e. g. memory subsystem of JVM. These are modelled using 2 separate relationships in inventory. The containment aspect is modelled by the contains relationship and the hierarchy aspect is modelled by the isParentOf relationship. When a contains relationship is established between 2 resources, the isParentOf is automagically added by the inventory.
2. Custom hierarchies can be defined between arbitrary resources, regardless of their containment in other resources. These can be useful to compose ad-hoc "groupings" of resources

This relationship cannot form loops (similarly to contains) but allows for 1 resource having more than 1 parent. This is allowed so that custom/parallel resource hierarchies can be created that share the same resources (the most obvious example of this is that a resource that has been discovered and "hierarchized" by a feed can also be put "under" a custom, user-defined, resource).

When deleting a resource, all its contained child resources are deleted along with it as mandated by the contract of the contains relationship.

Method Detail

values

public static Relationships.WellKnown[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (Relationships.WellKnown c : Relationships.WellKnown.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static Relationships.WellKnown valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null