org.scalatest.enablers.Existence.scala Maven / Gradle / Ivy
/*
* Copyright 2001-2013 Artima, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.scalatest.enablers
/**
* Supertrait for typeclasses that enable the exist matcher syntax.
*
*
* An Existence[S] provides access to the "existence nature" of type S in such
* a way that exist matcher syntax can be used with type S. A S
* can be any type for which the concept of existence makes sense, such as java.io.File. ScalaTest provides
* implicit implementations for java.io.File. You can enable the exist matcher syntax on your own
* type U by defining a Existence[U] for the type and making it available implicitly.
*
*
* ScalaTest provides an implicit Existence instance for java.io.File
* in the Existence companion object.
*
*/
trait Existence[-S] {
/**
* Determines whether the passed thing exists, i.e., whether the passed java.io.File exists.
*
* @param thing the thing to check for existence
* @return true if passed thing exists, false otherwise
*/
def exists(thing: S): Boolean
}
/**
* Companion object for Existence that provides implicit implementations for java.io.File.
*/
object Existence {
/**
* Enable Existence implementation for java.io.File
*
* @tparam FILE any subtype of java.io.File
* @return Existence[FILE] that supports java.io.File in exist syntax
*/
implicit def existenceOfFile[FILE <: java.io.File]: Existence[FILE] =
new Existence[FILE] {
def exists(file: FILE): Boolean = file.exists
}
}