diff --git a/src/main/java/xyz/zhouxy/plusone/commons/function/DoubleToOptionalFunction.java b/src/main/java/xyz/zhouxy/plusone/commons/function/DoubleToOptionalFunction.java
new file mode 100644
index 0000000..7806655
--- /dev/null
+++ b/src/main/java/xyz/zhouxy/plusone/commons/function/DoubleToOptionalFunction.java
@@ -0,0 +1,8 @@
+package xyz.zhouxy.plusone.commons.function;
+
+import java.util.Optional;
+import java.util.function.DoubleFunction;
+
+@FunctionalInterface
+public interface DoubleToOptionalFunction<R> extends DoubleFunction<Optional<R>> {
+}
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/function/IntToOptionalFunction.java b/src/main/java/xyz/zhouxy/plusone/commons/function/IntToOptionalFunction.java
new file mode 100644
index 0000000..e3a1bfb
--- /dev/null
+++ b/src/main/java/xyz/zhouxy/plusone/commons/function/IntToOptionalFunction.java
@@ -0,0 +1,8 @@
+package xyz.zhouxy.plusone.commons.function;
+
+import java.util.Optional;
+import java.util.function.IntFunction;
+
+@FunctionalInterface
+public interface IntToOptionalFunction<R> extends IntFunction<Optional<R>> {
+}
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/function/LongToOptionalFunction.java b/src/main/java/xyz/zhouxy/plusone/commons/function/LongToOptionalFunction.java
new file mode 100644
index 0000000..89d4b8b
--- /dev/null
+++ b/src/main/java/xyz/zhouxy/plusone/commons/function/LongToOptionalFunction.java
@@ -0,0 +1,8 @@
+package xyz.zhouxy.plusone.commons.function;
+
+import java.util.Optional;
+import java.util.function.LongFunction;
+
+@FunctionalInterface
+public interface LongToOptionalFunction<R> extends LongFunction<Optional<R>> {
+}
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/function/OptionalDoubleSupplier.java b/src/main/java/xyz/zhouxy/plusone/commons/function/OptionalDoubleSupplier.java
new file mode 100644
index 0000000..ea79107
--- /dev/null
+++ b/src/main/java/xyz/zhouxy/plusone/commons/function/OptionalDoubleSupplier.java
@@ -0,0 +1,8 @@
+package xyz.zhouxy.plusone.commons.function;
+
+import java.util.OptionalDouble;
+import java.util.function.Supplier;
+
+@FunctionalInterface
+public interface OptionalDoubleSupplier extends Supplier<OptionalDouble> {
+}
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/function/OptionalIntSupplier.java b/src/main/java/xyz/zhouxy/plusone/commons/function/OptionalIntSupplier.java
new file mode 100644
index 0000000..fb9e9a8
--- /dev/null
+++ b/src/main/java/xyz/zhouxy/plusone/commons/function/OptionalIntSupplier.java
@@ -0,0 +1,8 @@
+package xyz.zhouxy.plusone.commons.function;
+
+import java.util.OptionalInt;
+import java.util.function.Supplier;
+
+@FunctionalInterface
+public interface OptionalIntSupplier extends Supplier<OptionalInt> {
+}
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/function/OptionalLongSupplier.java b/src/main/java/xyz/zhouxy/plusone/commons/function/OptionalLongSupplier.java
new file mode 100644
index 0000000..1c0f9d5
--- /dev/null
+++ b/src/main/java/xyz/zhouxy/plusone/commons/function/OptionalLongSupplier.java
@@ -0,0 +1,8 @@
+package xyz.zhouxy.plusone.commons.function;
+
+import java.util.OptionalLong;
+import java.util.function.Supplier;
+
+@FunctionalInterface
+public interface OptionalLongSupplier extends Supplier<OptionalLong> {
+}
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/function/OptionalSupplier.java b/src/main/java/xyz/zhouxy/plusone/commons/function/OptionalSupplier.java
new file mode 100644
index 0000000..1b9098a
--- /dev/null
+++ b/src/main/java/xyz/zhouxy/plusone/commons/function/OptionalSupplier.java
@@ -0,0 +1,8 @@
+package xyz.zhouxy.plusone.commons.function;
+
+import java.util.Optional;
+import java.util.function.Supplier;
+
+@FunctionalInterface
+public interface OptionalSupplier<T> extends Supplier<Optional<T>> {
+}
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/function/ToOptionalBiFunction.java b/src/main/java/xyz/zhouxy/plusone/commons/function/ToOptionalBiFunction.java
new file mode 100644
index 0000000..25ece43
--- /dev/null
+++ b/src/main/java/xyz/zhouxy/plusone/commons/function/ToOptionalBiFunction.java
@@ -0,0 +1,8 @@
+package xyz.zhouxy.plusone.commons.function;
+
+import java.util.Optional;
+import java.util.function.BiFunction;
+
+@FunctionalInterface
+public interface ToOptionalBiFunction<T, U, R> extends BiFunction<T, U, Optional<R>> {
+}
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/function/ToOptionalDoubleFunction.java b/src/main/java/xyz/zhouxy/plusone/commons/function/ToOptionalDoubleFunction.java
new file mode 100644
index 0000000..67ec3e7
--- /dev/null
+++ b/src/main/java/xyz/zhouxy/plusone/commons/function/ToOptionalDoubleFunction.java
@@ -0,0 +1,8 @@
+package xyz.zhouxy.plusone.commons.function;
+
+import java.util.OptionalDouble;
+import java.util.function.Function;
+
+@FunctionalInterface
+public interface ToOptionalDoubleFunction<T> extends Function<T, OptionalDouble> {
+}
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/function/ToOptionalFunction.java b/src/main/java/xyz/zhouxy/plusone/commons/function/ToOptionalFunction.java
new file mode 100644
index 0000000..58125e9
--- /dev/null
+++ b/src/main/java/xyz/zhouxy/plusone/commons/function/ToOptionalFunction.java
@@ -0,0 +1,8 @@
+package xyz.zhouxy.plusone.commons.function;
+
+import java.util.Optional;
+import java.util.function.Function;
+
+@FunctionalInterface
+public interface ToOptionalFunction<T, R> extends Function<T, Optional<R>> {
+}
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/function/ToOptionalIntFunction.java b/src/main/java/xyz/zhouxy/plusone/commons/function/ToOptionalIntFunction.java
new file mode 100644
index 0000000..07078f2
--- /dev/null
+++ b/src/main/java/xyz/zhouxy/plusone/commons/function/ToOptionalIntFunction.java
@@ -0,0 +1,8 @@
+package xyz.zhouxy.plusone.commons.function;
+
+import java.util.OptionalInt;
+import java.util.function.Function;
+
+@FunctionalInterface
+public interface ToOptionalIntFunction<T> extends Function<T, OptionalInt> {
+}
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/function/ToOptionalLongFunction.java b/src/main/java/xyz/zhouxy/plusone/commons/function/ToOptionalLongFunction.java
new file mode 100644
index 0000000..b968c56
--- /dev/null
+++ b/src/main/java/xyz/zhouxy/plusone/commons/function/ToOptionalLongFunction.java
@@ -0,0 +1,8 @@
+package xyz.zhouxy.plusone.commons.function;
+
+import java.util.OptionalLong;
+import java.util.function.Function;
+
+@FunctionalInterface
+public interface ToOptionalLongFunction<T> extends Function<T, OptionalLong> {
+}