com.hotels.styx.server

Class PathTrie<T>

java.lang.Object

com.hotels.styx.server.PathTrie<T>

Type Parameters:

T - the type of mapped values

public class PathTrie<T>
extends Object

Stores URL path string and ID mappings for a longest match retrieval. The mappings are configured with addEntry() method, while the idOf() method performs the best match ID retrieval. A configured path is considered "best" when it has the longest path prefix with the path presented for the idOf() method. An application ID associated with path "/" or "/*" is a default path. If a path presented to idOf() doesn't match with anything else, then an application ID associated with default path is returned. Note about URL mappings: 1. Trailing "/" in a configured path denotes (as you might expect) a sub-path. Any matching URL must be a "longer" match to be considered. For example, consider a mapping "/foo/ -> 2". Now, an idOf("foo/bar/blah"), idOf("/foo/") will return a match==2, but idOf("/foo") would not. 2. Note that trailing "/" and "/*" are equivalent. 3. A configured path that does not end with "/" or "/*" must be matched exactly. For example, a mapping "/foo/bar -> 2" will only match with path "/foo/bar", but not with "/foo/bar/" nor "/foo/bar/baz". Implementation notes: - Paths are stored in a tree structure to facilitate longest matching prefix searches. - Each node represents an individual name component in a path. Each leaf node in a tree is guaranteed to have an ID configured as a value. This guarantee does not hold for intermediate nodes. An intermediate node may or may not contain a configured ID value. Only nodes that have an ID configured will be considered being part of a successful longest-prefix match. For example: Mappings "/foo/bar/A -> 1" and "foo/bar/B -> 2" will result in a following, where intermediate nodes "foo" and "bar" do not have an associated application id. [root] | foo | bar / \ A(1) B(2) - To differentiate between sub-path matching vs. exact path matching, any sub-path mappings are stored in a special node "/" under the relevant name node. For example, consider mappings: addEntry("/foo/bar", 1); addEntry("/foo/bar/", 2); This would result in a following tree: [root] | "foo" | "bar" (= 1) <- matches "/foo/bar" only | "/" (= 2) <- matches any sub-path of "/foo/bar/..."

Constructor Summary

Constructors

Constructor and Description
PathTrie() Construct a new matcher.

Method Summary

Modifier and Type	Method and Description
Optional<T>	get(String path) ID value associated with path.
void	printContent()
void	put(String path, T value) Add a new entry.
T	remove(String path)

Methods inherited from class java.lang.Object

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

Constructor Detail

PathTrie

public PathTrie()

Construct a new matcher.

Method Detail

put

public void put(String path,
                T value)

Add a new entry.

Parameters:

path - path as string

value - value to map path to

get

public Optional<T> get(String path)

ID value associated with path.

Parameters:

path - path as string

Returns:

associated ID if existent

remove

public T remove(String path)

printContent

public void printContent()