Add lists utils

1 files changed, 30 insertions, 5 deletions

diff --git a/src/ch/epfl/xblast/Lists.java b/src/ch/epfl/xblast/Lists.java
index 777fab2..7e3ba5e 100644
--- a/src/ch/epfl/xblast/Lists.java
+++ b/src/ch/epfl/xblast/Lists.java
@@ -2,7 +2,6 @@ package ch.epfl.xblast;
 
 import java.util.*;
 import java.util.stream.Collectors;
-import java.util.stream.IntStream;
 import java.util.stream.Stream;
 
 /**
@@ -207,10 +206,36 @@ public final class Lists {
         if (Objects.isNull(kl) || Objects.isNull(vl) || kl.size() != vl.size())
             throw new IllegalArgumentException();
 
-        return Collections.unmodifiableMap(IntStream
-                .range(0, kl.size()).mapToObj(i -> i)
-                .filter(i -> Objects.nonNull(vl.get(i)))
-                .collect(Collectors.toMap(kl::get, vl::get)));
+        Map<K, V> m = new HashMap<>();
+        Iterator<K> ki = kl.iterator();
+        Iterator<V> vi = vl.iterator();
+
+        while (ki.hasNext() && vi.hasNext())
+            m.put(ki.next(), vi.next());
+
+        return Collections.unmodifiableMap(m);
+    }
+
+    /**
+     * Maps linearly two lists, adjusting their respective size by truncating the key list or completing the value list
+     * with null values.
+     *
+     * @param kl  the keys list
+     * @param vl  the values list
+     * @param <K> the key type
+     * @param <V> the value type
+     * @return the map
+     */
+    public static <K, V> Map<K, V> linearAdjustedMap(List<K> kl, List<V> vl) {
+        if (Objects.isNull(kl) || Objects.isNull(vl))
+            throw new IllegalArgumentException();
+
+        if (kl.size() <= vl.size())
+            return Lists.linearMap(kl, vl.subList(0, kl.size()));
+        else
+            return Lists.linearMap(
+                    kl,
+                    concatenated(Arrays.asList(vl, Collections.nCopies(kl.size() - vl.size(), null))));
     }
 
     /**