add filter util

Author: SirCotare

src/main/java/it/aboutbits/springboot/toolbox/util/FilterUtil.java

@@ -0,0 +1,72 @@
+package it.aboutbits.springboot.toolbox.util;
+
+import lombok.NonNull;
+import org.springframework.data.util.Streamable;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Set;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+/**
+ * This is a collection of tools to simply filter items to a new collection or stream.
+ * <p>
+ * The returned collections are unmodifiable.
+ */
+public final class FilterUtil {
+    private FilterUtil() {
+    }
+
+    public static <T> Set<T> filterToSet(@NonNull Collection<T> items, @NonNull Predicate<T> filter) {
+        return items.stream()
+                .filter(filter)
+                .collect(Collectors.toUnmodifiableSet());
+    }
+
+    public static <T> Set<T> filterToSet(@NonNull Streamable<T> items, @NonNull Predicate<T> filter) {
+        return items.stream()
+                .filter(filter)
+                .collect(Collectors.toUnmodifiableSet());
+    }
+
+    public static <T> Set<T> filterToSet(@NonNull Stream<T> items, @NonNull Predicate<T> filter) {
+        return items
+                .filter(filter)
+                .collect(Collectors.toUnmodifiableSet());
+    }
+
+    public static <T> List<T> filterToList(@NonNull Collection<T> items, @NonNull Predicate<T> filter) {
+        return items.stream()
+                .filter(filter)
+                .toList();
+    }
+
+    public static <T> List<T> filterToList(@NonNull Streamable<T> items, @NonNull Predicate<T> filter) {
+        return items.stream()
+                .filter(filter)
+                .toList();
+    }
+
+    public static <T> List<T> filterToList(@NonNull Stream<T> items, @NonNull Predicate<T> filter) {
+        return items
+                .filter(filter)
+                .toList();
+    }
+
+    public static <T> Stream<T> filterToStream(@NonNull Collection<T> items, @NonNull Predicate<T> filter) {
+        return items.stream()
+                .filter(filter);
+    }
+
+    public static <T> Stream<T> filterToStream(@NonNull Streamable<T> items, @NonNull Predicate<T> filter) {
+        return items.stream()
+                .filter(filter);
+    }
+
+    public static <T> Stream<T> filterToStream(@NonNull Stream<T> items, @NonNull Predicate<T> filter) {
+        return items
+                .filter(filter);
+    }
+}