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Cleaned up API docs for Relation.

This commit is contained in:
Mark Harrah 2013-08-16 14:21:45 -04:00
parent 9614c4f95a
commit a2ab8a3630
1 changed files with 28 additions and 14 deletions
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42
util/relation/src/main/scala/sbt/Relation.scala
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@ -9,7 +9,12 @@ object Relation
{
/** Constructs a new immutable, finite relation that is initially empty. */
def empty[A,B]: Relation[A,B] = make(Map.empty, Map.empty)
/** Constructs a [[Relation]] from underlying `forward` and `reverse` representations, without checking that they are consistent.
* This is a low-level constructor and the alternatives [[empty]] and [[reconstruct]] should be preferred. */
def make[A,B](forward: Map[A,Set[B]], reverse: Map[B, Set[A]]): Relation[A,B] = new MRelation(forward, reverse)
/** Constructs a relation such that for every entry `_1 -> _2s` in `forward` and every `_2` in `_2s`, `(_1, _2)` is in the relation. */
def reconstruct[A,B](forward: Map[A, Set[B]]): Relation[A,B] =
{
val reversePairs = for( (a,bs) <- forward.view; b <- bs.view) yield (b, a)
@ -39,47 +44,56 @@ object Relation
/** Binary relation between A and B. It is a set of pairs (_1, _2) for _1 in A, _2 in B. */
trait Relation[A,B]
{
/** Returns the set of all _2s such that (_1, _2) is in this relation. */
/** Returns the set of all `_2`s such that `(_1, _2)` is in this relation. */
def forward(_1: A): Set[B]
/** Returns the set of all _1s such that (_1, _2) is in this relation. */
/** Returns the set of all `_1`s such that `(_1, _2)` is in this relation. */
def reverse(_2: B): Set[A]
/** Includes the relation given by `pair`. */
/** Includes `pair` in the relation. */
def +(pair: (A, B)): Relation[A,B]
/** Includes the relation (a, b). */
/** Includes `(a, b)` in the relation. */
def +(a: A, b: B): Relation[A,B]
/** Includes the relations (a, b) for all b in bs. */
/** Includes in the relation `(a, b)` for all `b` in `bs`. */
def +(a: A, bs: Traversable[B]): Relation[A,B]
/** Returns the union of the relation r with this relation. */
/** Returns the union of the relation `r` with this relation. */
def ++(r: Relation[A,B]): Relation[A,B]
/** Includes the given relations. */
/** Includes the given pairs in this relation. */
def ++(rs: Traversable[(A,B)]): Relation[A,B]
/** Removes all relations (_1, _2) for all _1 in _1s. */
/** Removes all elements `(_1, _2)` for all `_1` in `_1s` from this relation. */
def --(_1s: Traversable[A]): Relation[A,B]
/** Removes all `pairs` from this relation. */
def --(pairs: TraversableOnce[(A,B)]): Relation[A,B]
/** Removes all pairs (_1, _2) from this relation. */
/** Removes all pairs `(_1, _2)` from this relation. */
def -(_1: A): Relation[A,B]
/** Removes `pair` from this relation. */
def -(pair: (A,B)): Relation[A,B]
/** Returns the set of all _1s such that (_1, _2) is in this relation. */
/** Returns the set of all `_1`s such that `(_1, _2)` is in this relation. */
def _1s: collection.Set[A]
/** Returns the set of all _2s such that (_1, _2) is in this relation. */
/** Returns the set of all `_2`s such that `(_1, _2)` is in this relation. */
def _2s: collection.Set[B]
/** Returns the number of pairs in this relation */
def size: Int
/** Returns true iff (a,b) is in this relation*/
/** Returns true iff `(a,b)` is in this relation*/
def contains(a: A, b: B): Boolean
/** Returns a relation with only pairs (a,b) for which f(a,b) is true.*/
/** Returns a relation with only pairs `(a,b)` for which `f(a,b)` is true.*/
def filter(f: (A,B) => Boolean): Relation[A,B]
/** Partitions this relation into a map of relations according to some discriminator function. */
/** Partitions this relation into a map of relations according to some discriminator function `f`. */
def groupBy[K](f: ((A,B)) => K): Map[K, Relation[A,B]]
/** Returns all pairs in this relation.*/
def all: Traversable[(A,B)]
/** Represents this relation as a `Map` from a `_1` to the set of `_2`s such that `(_1, _2)` is in this relation.
*
* Specifically, there is one entry for each `_1` such that `(_1, _2)` is in this relation for some `_2`.
* The value associated with a given `_1` is the set of all `_2`s such that `(_1, _2)` is in this relation.*/
def forwardMap: Map[A, Set[B]]
/** Represents this relation as a `Map` from a `_2` to the set of `_1`s such that `(_1, _2)` is in this relation.
*
* Specifically, there is one entry for each `_2` such that `(_1, _2)` is in this relation for some `_1`.
* The value associated with a given `_2` is the set of all `_1`s such that `(_1, _2)` is in this relation.*/
def reverseMap: Map[B, Set[A]]
}
private final class MRelation[A,B](fwd: Map[A, Set[B]], rev: Map[B, Set[A]]) extends Relation[A,B]