Add IOBinaryOperator
MODIFY
src/changes/changes.xml
src/changes/changes.xml
@@ -360,7 +360,7 @@ The <action> type attribute can be add,update,fix,remove.
Add IOExceptionList.checkEmpty(List, Object).
</action>
<action dev="ggregory" type="add" due-to="Gary Gregory">
- Add IOBiConsumer, IOTriConsumer, IOComparator, IOUnaryOperator.
+ Add IOBiConsumer, IOTriConsumer, IOComparator, IOUnaryOperator, IOBinaryOperator.
</action>
<action dev="ggregory" type="add" due-to="Gary Gregory">
Add and reuse IOConsumer forAll(*), forEach(*), and forEachIndexed(*).

ADD
src/main/java/org/apache/commons/io/function/IOBinaryOperator.java
+/*
+ * 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.Objects;
+import java.util.function.BinaryOperator;
+
+/**
+ * Like {@link BinaryOperator} but throws {@link IOException}.
+ *
+ * @param <T> the type of the operands and result of the operator.
+ *
+ * @see IOBiFunction
+ * @see BinaryOperator
+ * @since 2.12.0
+ */
+@FunctionalInterface
+public interface IOBinaryOperator<T> extends IOBiFunction<T, T, T> {
+
+ /**
+ * Creates a {@link IOBinaryOperator} which returns the lesser of two elements according to the specified
+ * {@code Comparator}.
+ *
+ * @param <T> the type of the input arguments of the comparator
+ * @param comparator a {@code Comparator} for comparing the two values
+ * @return a {@code BinaryOperator} which returns the lesser of its operands, according to the supplied
+ * {@code Comparator}
+ * @throws NullPointerException if the argument is null
+ */
+ static <T> IOBinaryOperator<T> minBy(final IOComparator<? super T> comparator) {
+ Objects.requireNonNull(comparator);
+ return (a, b) -> comparator.compare(a, b) <= 0 ? a : b;
+ }
+
+ /**
+ * Creates a {@link IOBinaryOperator} which returns the greater of two elements according to the specified
+ * {@code Comparator}.
+ *
+ * @param <T> the type of the input arguments of the comparator
+ * @param comparator a {@code Comparator} for comparing the two values
+ * @return a {@code BinaryOperator} which returns the greater of its operands, according to the supplied
+ * {@code Comparator}
+ * @throws NullPointerException if the argument is null
+ */
+ static <T> IOBinaryOperator<T> maxBy(final IOComparator<? super T> comparator) {
+ Objects.requireNonNull(comparator);
+ return (a, b) -> comparator.compare(a, b) >= 0 ? a : b;
+ }
+
+ /**
+ * Creates a {@link BinaryOperator} for this instance that throws {@link UncheckedIOException} instead of
+ * {@link IOException}.
+ *
+ * @return an unchecked BiFunction.
+ */
+ default BinaryOperator<T> asBinaryOperator() {
+ return (t, u) -> Uncheck.apply(this, t, u);
+ }
+}

ADD
src/test/java/org/apache/commons/io/function/IOBinaryOperatorStreamTest.java
+/*
+ * 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 static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.fail;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.function.BiFunction;
+import java.util.function.BinaryOperator;
+import java.util.stream.Stream;
+
+import org.apache.commons.io.file.PathUtils;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests {@link IOBinaryOperator}.
+ */
+public class IOBinaryOperatorStreamTest {
+
+ private static final IOBinaryOperator<Path> MIN_BY_IO_BO = IOBinaryOperator.minBy(IOComparatorTest.REAL_PATH_COMP);
+ private static final BinaryOperator<Path> MIN_BY_BO = MIN_BY_IO_BO.asBinaryOperator();
+ private static final IOBinaryOperator<Path> MAX_BY_IO_BO = IOBinaryOperator.maxBy(IOComparatorTest.REAL_PATH_COMP);
+ private static final BinaryOperator<Path> MAX_BY_BO = MAX_BY_IO_BO.asBinaryOperator();
+ private static final IOBinaryOperator<Path> REAL_PATH_IO_BO = (t, u) -> t.toRealPath();
+ private static final BinaryOperator<Path> REAL_PATH_BO = REAL_PATH_IO_BO.asBinaryOperator();
+
+ @Test
+ public void testAsBinaryOperator() {
+ assertThrows(UncheckedIOException.class,
+ () -> Stream.of(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_A).reduce((TestUtils.<Path>throwingIOBinaryOperator()).asBinaryOperator()).get());
+ assertEquals(TestConstants.ABS_PATH_A, Stream.of(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_A).reduce(MAX_BY_BO).get());
+ assertEquals(TestConstants.ABS_PATH_A, Stream.of(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_A).reduce(MIN_BY_BO).get());
+ }
+
+ @Test
+ public void testMaxBy() throws IOException {
+ assertEquals(TestConstants.ABS_PATH_A, Stream.of(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_A).reduce(MAX_BY_BO).get());
+ // in-line lambda ok:
+ final IOBinaryOperator<Path> binIoOp = IOBinaryOperator.maxBy((t, u) -> t.toRealPath().compareTo(u));
+ final BiFunction<Path, Path, Path> asBiFunction = binIoOp.asBiFunction();
+ final BinaryOperator<Path> asBinaryOperator = binIoOp.asBinaryOperator();
+ assertEquals(TestConstants.ABS_PATH_B, asBiFunction.apply(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_B));
+ assertEquals(TestConstants.ABS_PATH_B, asBinaryOperator.apply(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_B));
+ //
+ assertEquals(TestConstants.ABS_PATH_A, Stream.of(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_A).reduce(asBinaryOperator).get());
+ assertEquals(TestConstants.ABS_PATH_B, Stream.of(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_B).reduce(asBinaryOperator).get());
+ assertEquals(TestConstants.ABS_PATH_B, Stream.of(TestConstants.ABS_PATH_B, TestConstants.ABS_PATH_A).reduce(asBinaryOperator).get());
+ }
+
+ @Test
+ public void testMinBy() throws IOException {
+ assertEquals(TestConstants.ABS_PATH_A, Stream.of(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_A).reduce(MIN_BY_BO).get());
+ // in-line lambda ok:
+ final IOBinaryOperator<Path> binIoOp = IOBinaryOperator.minBy((t, u) -> t.toRealPath().compareTo(u));
+ final BiFunction<Path, Path, Path> asBiFunction = binIoOp.asBiFunction();
+ final BinaryOperator<Path> asBinaryOperator = binIoOp.asBinaryOperator();
+ assertEquals(TestConstants.ABS_PATH_A, asBiFunction.apply(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_B));
+ assertEquals(TestConstants.ABS_PATH_A, asBinaryOperator.apply(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_B));
+ //
+ assertEquals(TestConstants.ABS_PATH_A, Stream.of(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_A).reduce(asBinaryOperator).get());
+ assertEquals(TestConstants.ABS_PATH_A, Stream.of(TestConstants.ABS_PATH_A, TestConstants.ABS_PATH_B).reduce(asBinaryOperator).get());
+ assertEquals(TestConstants.ABS_PATH_A, Stream.of(TestConstants.ABS_PATH_B, TestConstants.ABS_PATH_A).reduce(asBinaryOperator).get());
+ }
+
+ @Test
+ public void testReduce() throws IOException {
+ // A silly example to pass in a IOBinaryOperator.
+ final Path current = PathUtils.current();
+ final Path expected = Files.list(current).reduce((t, u) -> {
+ try {
+ return t.toRealPath();
+ } catch (final IOException e) {
+ return fail(e);
+ }
+ }).get();
+ assertEquals(expected, Files.list(current).reduce(REAL_PATH_BO).get());
+ }
+
+}

MODIFY
src/test/java/org/apache/commons/io/function/TestConstants.java
src/test/java/org/apache/commons/io/function/TestConstants.java
throw new IOException("Failure");
};
+ static IOBinaryOperator<?> THROWING_IO_BINARY_OPERATOR = (t, u) -> throwIOException();
+
static IOComparator<Object> THROWING_IO_COMPARATOR = (t, u) -> throwIOException();
static IOConsumer<Object> THROWING_IO_CONSUMER = t -> {

MODIFY
src/test/java/org/apache/commons/io/function/TestUtils.java
src/test/java/org/apache/commons/io/function/TestUtils.java
return ref.get(); // same as update
}
+ @SuppressWarnings("unchecked")
+ static <T> IOBinaryOperator<T> throwingIOBinaryOperator() {
+ return (IOBinaryOperator<T>) TestConstants.THROWING_IO_BINARY_OPERATOR;
+ }
+
@SuppressWarnings("unchecked")
static <T> IOUnaryOperator<T> throwingIOUnaryOperator() {
return (IOUnaryOperator<T>) TestConstants.THROWING_IO_UNARY_OPERATOR;

Add IOBinaryOperator