Add IOUnaryOperator

1 files changed, 56 insertions, 0 deletions

diff --git a/src/main/java/org/apache/commons/io/function/IOUnaryOperator.java b/src/main/java/org/apache/commons/io/function/IOUnaryOperator.java
new file mode 100644
index 00000000..cf6445d5
--- /dev/null
+++ b/src/main/java/org/apache/commons/io/function/IOUnaryOperator.java
@@ -0,0 +1,56 @@
+/*
+ * 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.io.function;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.util.function.UnaryOperator;
+
+/**
+ * Like {@link UnaryOperator} but throws {@link IOException}.
+ *
+ * @param <T> the type of the operand and result of the operator.
+ *
+ * @see UnaryOperator
+ * @see IOFunction
+ * @since 2.12.0
+ */
+@FunctionalInterface
+public interface IOUnaryOperator<T> extends IOFunction<T, T> {
+
+    /**
+     * Creates a unary operator that always returns its input argument.
+     *
+     * @param <T> the type of the input and output of the operator.
+     * @return a unary operator that always returns its input argument.
+     */
+    static <T> IOUnaryOperator<T> identity() {
+        return t -> t;
+    }
+
+    /**
+     * Creates a {@link UnaryOperator} for this instance that throws {@link UncheckedIOException} instead of
+     * {@link IOException}.
+     *
+     * @return an unchecked BiFunction.
+     */
+    default UnaryOperator<T> asUnaryOperator() {
+        return t -> Uncheck.apply(this, t);
+    }
+
+}