split the filter method into filter(predicate) and filterTo(result, predicate) for easier completion & avoid confusion - seems 2 methods is better than the default arguments approach

This commit is contained in:
James Strachan
2012-02-29 09:51:22 +00:00
parent 91f531357c
commit 27ece9c765
2 changed files with 9 additions and 14 deletions
-11
View File
@@ -8,17 +8,6 @@ Filters given iterator
*/
inline fun <T> java.util.Iterator<T>.filter(f: (T)-> Boolean) : java.util.Iterator<T> = FilterIterator<T>(this, f)
/*
Adds filtered elements in to given container
*/
inline fun <T,U : Collection<in T>> java.lang.Iterable<T>.filterTo(var container: U, filter: (T)->Boolean) : U {
for(element in this) {
if(filter(element))
container.add(element)
}
return container
}
/*
Create iterator filtering given java.lang.Iterable
*/
+9 -3
View File
@@ -41,8 +41,11 @@ inline fun <T> java.lang.Iterable<T>.find(predicate: (T)-> Boolean) : T? {
return null
}
/** Returns a new collection containing all elements in this collection which match the given predicate */
inline fun <T> java.lang.Iterable<T>.filter(result: Collection<T> = ArrayList<T>(), predicate: (T)-> Boolean) : Collection<T> {
/** Returns a new List containing all elements in this collection which match the given predicate */
inline fun <T> java.lang.Iterable<T>.filter(predicate: (T)-> Boolean) : Collection<T> = filterTo(java.util.ArrayList<T>(), predicate)
/** Filters all elements in this collection which match the given predicate into the given result collection */
inline fun <T, C: Collection<in T>> java.lang.Iterable<T>.filterTo(result: C, predicate: (T)-> Boolean) : C {
for (elem in this) {
if (predicate(elem))
result.add(elem)
@@ -51,7 +54,10 @@ inline fun <T> java.lang.Iterable<T>.filter(result: Collection<T> = ArrayList<T>
}
/** Returns a new collection containing all elements in this collection which do not match the given predicate */
inline fun <T> java.lang.Iterable<T>.filterNot(result: Collection<T> = ArrayList<T>(), predicate: (T)-> Boolean) : Collection<T> {
inline fun <T> java.lang.Iterable<T>.filterNot(predicate: (T)-> Boolean) : Collection<T> = filterNotTo(ArrayList<T>(), predicate)
/** Returns a new collection containing all elements in this collection which do not match the given predicate */
inline fun <T, C: Collection<in T>> java.lang.Iterable<T>.filterNotTo(result: C, predicate: (T)-> Boolean) : C {
for (elem in this) {
if (!predicate(elem))
result.add(elem)