Add IOComparator

2 files changed, 75 insertions, 0 deletions

diff --git a/src/main/java/org/apache/commons/io/function/IOComparator.java b/src/main/java/org/apache/commons/io/function/IOComparator.java
new file mode 100644
index 00000000..01a5132c
--- /dev/null
+++ b/src/main/java/org/apache/commons/io/function/IOComparator.java
@@ -0,0 +1,57 @@
+/*
+ * 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.Comparator;
+
+/**
+ * Like {@link Comparator} but throws {@link IOException}.
+ *
+ * @param <T> the type of objects that may be compared by this comparator
+ *
+ * @see Comparator
+ * @since 2.12.0
+ */
+@FunctionalInterface
+public interface IOComparator<T> {
+
+    /**
+     * Creates a {@link Comparator} for this instance that throws {@link UncheckedIOException} instead of
+     * {@link IOException}.
+     *
+     * @return an UncheckedIOException BiFunction.
+     */
+    default Comparator<T> asComparator() {
+        return (t, u) -> Uncheck.compare(this, t, u);
+    }
+
+    /**
+     * Like {@link Comparator#compare(Object, Object)} but throws {@link IOException}.
+     *
+     * @param o1 the first object to be compared.
+     * @param o2 the second object to be compared.
+     * @return a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than
+     *         the second.
+     * @throws NullPointerException if an argument is null and this comparator does not permit null arguments
+     * @throws ClassCastException if the arguments' types prevent them from being compared by this comparator.
+     * @throws IOException if an I/O error occurs.
+     */
+    int compare(T o1, T o2) throws IOException;
+}
diff --git a/src/main/java/org/apache/commons/io/function/Uncheck.java b/src/main/java/org/apache/commons/io/function/Uncheck.java
index 81b3b4ad..89ca0d49 100644
--- a/src/main/java/org/apache/commons/io/function/Uncheck.java
+++ b/src/main/java/org/apache/commons/io/function/Uncheck.java
@@ -166,6 +166,24 @@ public class Uncheck {
     }
 
     /**
+     * Compares the arguments with the comparator.
+     *
+     * @param <T> the first function argument type.
+     * @param comparator the function.
+     * @param t the first function argument.
+     * @param u the second function argument.
+     * @return the comparator result.
+     * @throws UncheckedIOException if an I/O error occurs.
+     */
+    public static <T> int compare(final IOComparator<T> comparator, final T t, final T u) {
+        try {
+            return comparator.compare(t, u);
+        } catch (final IOException e) {
+            throw wrap(e);
+        }
+    }
+
+    /**
      * Gets the result from an IO supplier.
      *
      * @param <T> the return type of the operations.