/
AbstractSet.kt
48 lines (42 loc) · 1.55 KB
/
AbstractSet.kt
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/*
* Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
* that can be found in the license/LICENSE.txt file.
*/
package kotlin.collections
/**
* Provides a skeletal implementation of the read-only [Set] interface.
*
* This class is intended to help implementing read-only sets so it doesn't support concurrent modification tracking.
*
* @param E the type of elements contained in the set. The set is covariant on its element type.
*/
@SinceKotlin("1.1")
public abstract class AbstractSet<out E> protected constructor() : AbstractCollection<E>(), Set<E> {
/**
* Compares this set with other set instance with the unordered structural equality.
*
* @return true, if [other] instance is a [Set] of the same size, all elements of which are contained in this set.
*/
override fun equals(other: Any?): Boolean {
if (other === this) return true
if (other !is Set<*>) return false
return setEquals(this, other)
}
/**
* Returns the hash code value for this set.
*/
override fun hashCode(): Int = unorderedHashCode(this)
internal companion object {
internal fun unorderedHashCode(c: Collection<*>): Int {
var hashCode = 0
for (element in c) {
hashCode += (element?.hashCode() ?: 0)
}
return hashCode
}
internal fun setEquals(c: Set<*>, other: Set<*>): Boolean {
if (c.size != other.size) return false
return c.containsAll(other)
}
}
}