Archery
Overview
Archery is a two-dimensional R-Tree written in Scala. The implementation is immutable: adding and removing points from the tree produces a new tree, leaving the old one untouched. Due to structural sharing this operation is quite efficient.
The name "archery" is a corruption of the word "R-Tree".
Getting Archery
Archery is published to bintray using the bintray-sbt plugin. Archery is available for Scala 2.10 and Scala 2.11.
If you use SBT, you can include Archery via the following build.sbt
snippet:
resolvers += "bintray/meetup" at "http://dl.bintray.com/meetup/maven"
libraryDependencies += "com.meetup" %% "archery" % "0.4.0"
For Maven or Ivy, you'll use the same resolver URL but you'll need a slightly different artifact name (the example is for Scala 2.11):
org=com.meetup
name=archery_2.11
rev=0.4.0
Example Usage
import archery._
// create some entries
val alice = Entry(Point(9.12F, -4.9F), "alice")
val bob = Entry(Point(2.3F, 4.6F), "bob")
val candice = Entry(Point(4.7F, -1.9F), "candice")
val doug = Entry(Point(5.5F, -3.2F), "doug")
// build a tree with three points
val tree1: RTree[String] = RTree(alice, bob, candice)
// add "doug"
val tree2: RTree[String] = tree1.insert(doug)
// remove "bob"
val tree3: RTree[String] = tree2.remove(bob)
// search from (0,-4) to (10,6), will find "doug"
val bbox: Box = Box(0F, -4F, 10F, 6F)
val results: Seq[Entry[String]] = tree3.search(bbox)
// we can also just ask how many matching entries exist
val n: Int = tree3.count(bbox)
assert(results.length == n)
Contributing
If you find something that seems like a bug in Archery, or see confusing behavior, or find a place where the documentation or library could be better, please open an issue.
Pull requests are gladly accepted. The preferred strategy is to open an issue or pull request where the feature can be discussed. We can use the PR to collaborate on, and will merge it once everyone agrees on the change, the tests and docs are updated, etc.
Building Archery
Building this project requires SBT 0.13.x.
After you launch SBT, you can run the following commands:
compile
compile the project.test
run the tests.scalastyle
run the style-checking.benchmark/run
run the included timing benchmarks.console
load a scala REPL with archery on the classpath.
(Travis automatically runs test
and scalastyle
, so any issues
should also be detected when a pull request is opened.)
You can generate coverage statistics manually by running the following command from the command-line:
$ sbt clean coverage test coverageReport
Open core/target/scala-2.11/scoverage-report/index.html
in a web
browser to see local coverage.
Tests are written with ScalaTest and use the excellent ScalaCheck library for automated specification-based testing.
Test coverage is measured using sbt-scoverage and tracked at codecov.io.
The benchmarks are written against Rex Kerr's excellent library Thyme.
License
Archery is available to you under the MIT license. See the COPYING file for details.
Credits
Archery is maintained by Erik Osheim.
Copyright (c) 2013-2015 Meetup Inc.