scala.Product.scala Maven / Gradle / Ivy
/*
* Scala (https://www.scala-lang.org)
*
* Copyright EPFL and Lightbend, Inc.
*
* Licensed under Apache License 2.0
* (http://www.apache.org/licenses/LICENSE-2.0).
*
* See the NOTICE file distributed with this work for
* additional information regarding copyright ownership.
*/
package scala
/** Base trait for all products, which in the standard library include at
* least [[scala.Product1]] through [[scala.Product22]] and therefore also
* their subclasses [[scala.Tuple1]] through [[scala.Tuple22]]. In addition,
* all case classes implement `Product` with synthetically generated methods.
*
* @author Burak Emir
* @since 2.3
*/
trait Product extends Any with Equals {
/** The n^th^ element of this product, 0-based. In other words, for a
* product `A(x,,1,,, ..., x,,k,,)`, returns `x,,(n+1),,` where `0 <= n < k`.
*
* @param n the index of the element to return
* @throws IndexOutOfBoundsException
* @return the element `n` elements after the first element
*/
def productElement(n: Int): Any
/** The size of this product.
* @return for a product `A(x,,1,,, ..., x,,k,,)`, returns `k`
*/
def productArity: Int
/** An iterator over all the elements of this product.
* @return in the default implementation, an `Iterator[Any]`
*/
def productIterator: Iterator[Any] = new scala.collection.AbstractIterator[Any] {
private var c: Int = 0
private val cmax = productArity
def hasNext = c < cmax
def next() = { val result = productElement(c); c += 1; result }
}
/** A string used in the `toString` methods of derived classes.
* Implementations may override this method to prepend a string prefix
* to the result of `toString` methods.
*
* @return in the default implementation, the empty string
*/
def productPrefix = ""
}