1 files changed, 66 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/lang3/function/TriFunction.java b/src/main/java/org/apache/commons/lang3/function/TriFunction.java
new file mode 100644
index 000000000..7d8b81c50
--- /dev/null
+++ b/src/main/java/org/apache/commons/lang3/function/TriFunction.java
@@ -0,0 +1,66 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.lang3.function;
+
+import java.util.Objects;
+import java.util.function.Function;
+
+/**
+ * Represents a function that accepts three arguments and produces a result. This is the three-arity specialization of
+ * {@link Function}.
+ *
+ * <p>
+ * This is a <a href="package-summary.html">functional interface</a> whose functional method is
+ * {@link #apply(Object, Object, Object)}.
+ * </p>
+ *
+ * @param <T> the type of the first argument to the function
+ * @param <U> the type of the second argument to the function
+ * @param <V> the type of the third argument to the function
+ * @param <R> the type of the result of the function
+ *
+ * @see Function
+ * @since 3.12.0
+ */
+@FunctionalInterface
+public interface TriFunction<T, U, V, R> {
+
+    /**
+     * Applies this function to the given arguments.
+     *
+     * @param t the first function argument
+     * @param u the second function argument
+     * @param v the third function argument
+     * @return the function result
+     */
+    R apply(T t, U u, V v);
+
+    /**
+     * Returns a composed function that first applies this function to its input, and then applies the {@code after}
+     * function to the result. If evaluation of either function throws an exception, it is relayed to the caller of the
+     * composed function.
+     *
+     * @param <W> the type of output of the {@code after} function, and of the composed function
+     * @param after the function to apply after this function is applied
+     * @return a composed function that first applies this function and then applies the {@code after} function
+     * @throws NullPointerException if after is null
+     */
+    default <W> TriFunction<T, U, V, W> andThen(final Function<? super R, ? extends W> after) {
+        Objects.requireNonNull(after);
+        return (final T t, final U u, final V v) -> after.apply(apply(t, u, v));
+    }
+}