org.hawkular.inventory.base

Class Query

java.lang.Object

org.hawkular.inventory.base.Query

public final class Query
extends Object

Represents a tree of filters. The filters that are used to represent an inventory query (so that new query instances can be generated at will) form a tree because of the fact that environments can both contain resources or metrics directly or they can contain feeds that in turn contain the metrics and resources.

The API contains a method to traverse both of these kinds of "placement" of metrics or resources simultaneously. This is nice from a user perspective but creates problems in the impl, because using the relationships of the resources or metrics, one can construct queries, that would be able to branch multiple times and hence form a tree.

Since:

0.1.0

Author:

Lukas Krejci

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Query.Builder A low-level builder able to create new branches in the query tree.
static class	Query.SymmetricExtender Constructs a query fragment tree by extending all the leaves with a uniform set of filters at a time.

Method Summary

Modifier and Type	Method and Description
Query.Builder	asBuilder()
static Query	empty()
Query.SymmetricExtender	extend()
static Query.SymmetricExtender	filter()
static Filter[][]	filters(Query query) Converts the provided filter tree to a list of paths (array of filters).
QueryFragment[]	getFragments()
List<Query>	getSubTrees()
static Query.SymmetricExtender	path()
static Query	to(CanonicalPath entity)

Methods inherited from class java.lang.Object

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

Method Detail

filters

public static Filter[][] filters(Query query)

Converts the provided filter tree to a list of paths (array of filters). Each of the paths in the result represent 1 branch from the tree from root to some leaf.

Parameters:

query - the tree of filters

Returns:

the list of paths

to

public static Query to(CanonicalPath entity)

empty

public static Query empty()

Returns:

an empty query

filter

public static Query.SymmetricExtender filter()

Returns:

a symmetric builder that will start appending filter fragments to the query

path

public static Query.SymmetricExtender path()

Returns:

a symmetric builder that will start appending path fragments to the query

getFragments

public QueryFragment[] getFragments()

Returns:

the query fragments to compose the query from

getSubTrees

public List<Query> getSubTrees()

Returns:

the list of query "branches" from the point this query object represents.

asBuilder

public Query.Builder asBuilder()

Returns:

a new builder initialized to "contain" this query

extend

public Query.SymmetricExtender extend()

Returns:

a new symmetric builder initialized with this query