org.jetbrains.kotlin.utils.collections.kt Maven / Gradle / Ivy
/*
* Copyright 2010-2015 JetBrains s.r.o.
*
* 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.jetbrains.kotlin.utils
import java.util.*
fun Iterable.keysToMap(value: (K) -> V): Map {
return associateBy({ it }, value)
}
fun Iterable.keysToMapExceptNulls(value: (K) -> V?): Map {
val map = LinkedHashMap()
for (k in this) {
val v = value(k)
if (v != null) {
map[k] = v
}
}
return map
}
fun Iterable.mapToIndex(): Map {
val map = LinkedHashMap()
for ((index, k) in this.withIndex()) {
map[k] = index
}
return map
}
public inline fun MutableMap.getOrPutNullable(key: K, defaultValue: () -> V): V {
return if (!containsKey(key)) {
val answer = defaultValue()
put(key, answer)
answer
}
else {
get(key) as V
}
}
inline fun > C.ifEmpty(body: () -> C): C = if (isEmpty()) body() else this
inline fun Array.ifEmpty(body: () -> Array): Array = if (isEmpty()) body() else this
fun emptyOrSingletonList(item: T?): List = listOfNotNull(item)
fun MutableCollection.addIfNotNull(t: T?) {
if (t != null) add(t)
}
fun newHashMapWithExpectedSize(expectedSize: Int): HashMap {
return HashMap(if (expectedSize < 3) 3 else expectedSize + expectedSize / 3 + 1)
}
fun newHashSetWithExpectedSize(expectedSize: Int): HashSet {
return HashSet(if (expectedSize < 3) 3 else expectedSize + expectedSize / 3 + 1)
}
fun Collection.toReadOnlyList(): List =
when (size) {
0 -> emptyList()
1 -> listOf(first())
else -> ArrayList(this)
}
fun T?.singletonOrEmptyList(): List =
if (this != null) listOf(this) else emptyList()