Remove usages of Iterables.filter

2 files changed, 28 insertions, 0 deletions

diff --git a/src/main/java/org/zwobble/mammoth/internal/util/MammothIterables.java b/src/main/java/org/zwobble/mammoth/internal/util/MammothIterables.java
index c0231e0..fececa3 100644
--- a/src/main/java/org/zwobble/mammoth/internal/util/MammothIterables.java
+++ b/src/main/java/org/zwobble/mammoth/internal/util/MammothIterables.java
@@ -65,6 +65,29 @@ public class MammothIterables {
         };
     }
 
+    public static <T> Iterable<T> lazyFilter(Iterable<T> iterables, Predicate<T> predicate) {
+        return new Iterable<T>() {
+            @Override
+            public Iterator<T> iterator() {
+                return stream(iterables)
+                    .filter(predicate)
+                    .iterator();
+            }
+        };
+    }
+
+    public static <T, R> Iterable<R> lazyFilter(Iterable<T> iterables, Class<R> clazz) {
+        return new Iterable<R>() {
+            @Override
+            @SuppressWarnings("unchecked")
+            public Iterator<R> iterator() {
+                return (Iterator<R>) stream(iterables)
+                    .filter(clazz::isInstance)
+                    .iterator();
+            }
+        };
+    }
+
     private static <T, R> Iterator<R> map(Iterator<T> iterator, Function<T, R> function) {
         return new Iterator<R>() {
             @Override
diff --git a/src/main/java/org/zwobble/mammoth/internal/util/MammothLists.java b/src/main/java/org/zwobble/mammoth/internal/util/MammothLists.java
index 3519cd2..7f5b83c 100644
--- a/src/main/java/org/zwobble/mammoth/internal/util/MammothLists.java
+++ b/src/main/java/org/zwobble/mammoth/internal/util/MammothLists.java
@@ -6,6 +6,7 @@ import com.google.common.collect.Ordering;
 
 import java.util.List;
 import java.util.function.Function;
+import java.util.function.Predicate;
 import java.util.stream.Collectors;
 
 import static org.zwobble.mammoth.internal.util.MammothIterables.stream;
@@ -35,6 +36,10 @@ public class MammothLists {
         return ImmutableList.copyOf(Iterables.concat(first, second));
     }
 
+    public static <T> List<T> eagerFilter(Iterable<T> iterable, Predicate<T> predicate) {
+        return stream(iterable).filter(predicate).collect(Collectors.toList());
+    }
+
     public static <T, R> List<R> eagerMap(Iterable<T> iterable, Function<T, R> function) {
         return stream(iterable).map(function).collect(Collectors.toList());
     }