From 1ddc268fa686d8b3262175ca2979f3a4c6751803 Mon Sep 17 00:00:00 2001
From: nikgr117 <nikgr117@tlhw-4-4.ad.liu.se>
Date: Mon, 16 Sep 2019 22:41:05 +0200
Subject: [PATCH] Make where-method non-destructive
---
Task_A/src/Enumerable.java | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)
diff --git a/Task_A/src/Enumerable.java b/Task_A/src/Enumerable.java
index 177bce9..e664407 100644
--- a/Task_A/src/Enumerable.java
+++ b/Task_A/src/Enumerable.java
@@ -6,30 +6,37 @@ import java.util.Iterator;
public class Enumerable<T> implements Iterable<T> {
private Iterator<T> iterator;
+ private Collection<T> collection;
public Enumerable(Collection<T> collection) {
+ this.collection = collection;
this.iterator = collection.iterator();
}
Enumerable<T> where(IPredicate<T> predicate) {
- Iterator<T> oldIterator = iterator;
- this.iterator = new Iterator<T>() {
+ Enumerable<T> enumerable = new Enumerable<T>(this.collection);
+
+ enumerable.iterator = new Iterator<T>() {
+ Iterator<T> iterator = enumerable.iterator();
@Override
public boolean hasNext() {
- return oldIterator.hasNext();
+ return iterator.hasNext();
}
@Override
public T next() {
- T item = oldIterator.hasNext() ? oldIterator.next() : null;
- while (oldIterator.hasNext() && !predicate.accept(item)) {
- item = oldIterator.next();
+ T item = iterator.hasNext() ? iterator.next() : null;
+
+ while (iterator.hasNext() && !predicate.accept(item)) {
+ item = iterator.next();
}
- return item;
+
+ return predicate.accept(item) ? item : null;
}
};
- return this;
+
+ return enumerable;
}
@Override
--
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