garydgregory commented on code in PR #1270:
URL: https://github.com/apache/commons-lang/pull/1270#discussion_r1755500193
##########
src/main/java/org/apache/commons/lang3/ArrayUtils.java:
##########
@@ -1432,6 +1432,89 @@ public static <T> T arraycopy(final T source, final int
sourcePos, final T dest,
return dest;
}
+ /**
+ * Finds element in sorted array.
+ *
+ * @param array
+ * array sorted by key field
+ * @param key
+ * key to search for
+ * @param keyExtractor
+ * function to extract key from element
+ * @param comparator
+ * comparator for keys
+ *
+ * @return
+ * index of the search key, if it is contained in the array within
specified range; otherwise,
+ * (-first_greater - 1). The first_greater is the index of lowest
greater element in the list - if all elements
+ * are lower, the first_greater is defined as toIndex.
+ *
+ * @param <T>
+ * type of array element
+ * @param <K>
+ * type of key
+ */
+ public static <K, T> int binarySearch(
+ T[] array,
+ K key,
+ Function<T, K> keyExtractor, Comparator<? super K> comparator
+ ) {
+ return binarySearch(array, 0, array.length, key, keyExtractor,
comparator);
+ }
+
+ /**
+ * Finds element in sorted array, within range fromIndex - toIndex
(inclusive - exclusive).
Review Comment:
"FInds" -> "Searches" since the API is called "search".
For compatibility with `java.util.Arrays.binarySearch(T[], [int, int,] T,
Comparator<? super T>)`, you'll want to add range checks. From a call site's
POV, I think the functionality should be the same as
- `java.util.Arrays.binarySearch(T[], int, int, T, Comparator<? super T>)`
and
- `java.util.Arrays.binarySearch(T[], T, Comparator<? super T>)`
but with the addition of the key extractor feature.
Like `Arrays`, you might want to refactor into a `binarySearch0`.
##########
src/main/java/org/apache/commons/lang3/ArrayUtils.java:
##########
@@ -1432,6 +1432,89 @@ public static <T> T arraycopy(final T source, final int
sourcePos, final T dest,
return dest;
}
+ /**
+ * Finds element in sorted array.
Review Comment:
"FInds" -> "Searches" since the API is called "search".
##########
src/test/java/org/apache/commons/lang3/ArrayUtilsBinarySearchTest.java:
##########
@@ -0,0 +1,82 @@
+/*
+ * 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;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.stream.IntStream;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * Unit tests {@link ArrayUtils} binarySearch functions.
+ */
+public class ArrayUtilsBinarySearchTest extends AbstractLangTest {
+
+ @Test
+ public void binarySearch_whenEmpty_returnM1() {
+ Data[] list = createList();
+ int found = ArrayUtils.binarySearch(list, 0, Data::getValue,
Integer::compare);
+ assertEquals(-1, found);
+ }
+
+ @Test
+ public void binarySearch_whenExists_returnIndex() {
+ Data[] list = createList(0, 1, 2, 4, 7, 9, 12, 15, 17, 19, 25);
+ int found = ArrayUtils.binarySearch(list, 9, Data::getValue,
Integer::compare);
+ assertEquals(5, found);
+ }
+
+ @Test
+ public void binarySearch_whenNotExists_returnMinusInsertion() {
+ Data[] list = createList(0, 1, 2, 4, 7, 9, 12, 15, 17, 19, 25);
+ int found = ArrayUtils.binarySearch(list, 8, Data::getValue,
Integer::compare);
+ assertEquals(-6, found);
+ }
+
+ @Test
+ public void binarySearch_whenNotExistsBeginning_returnMinus1() {
+ Data[] list = createList(0, 1, 2, 4, 7, 9, 12, 15, 17, 19, 25);
+ int found = ArrayUtils.binarySearch(list, -3, Data::getValue,
Integer::compare);
+ assertEquals(-1, found);
+ }
+
+ @Test
+ public void binarySearch_whenNotExistsEnd_returnMinusLength() {
+ Data[] list = createList(0, 1, 2, 4, 7, 9, 12, 15, 17, 19, 25);
+ int found = ArrayUtils.binarySearch(list, 29, Data::getValue,
Integer::compare);
+ assertEquals(-(list.length + 1), found);
+ }
+
+ private Data[] createList(int... values) {
+ return IntStream.of(values).mapToObj(Data::new)
+ .toArray(Data[]::new);
+ }
+
+ public class Data
Review Comment:
The test fixture should be static and package-private.
##########
src/test/java/org/apache/commons/lang3/ArrayUtilsBinarySearchTest.java:
##########
@@ -0,0 +1,82 @@
+/*
+ * 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;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.stream.IntStream;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * Unit tests {@link ArrayUtils} binarySearch functions.
+ */
+public class ArrayUtilsBinarySearchTest extends AbstractLangTest {
+
+ @Test
+ public void binarySearch_whenEmpty_returnM1() {
+ Data[] list = createList();
+ int found = ArrayUtils.binarySearch(list, 0, Data::getValue,
Integer::compare);
+ assertEquals(-1, found);
+ }
+
+ @Test
+ public void binarySearch_whenExists_returnIndex() {
+ Data[] list = createList(0, 1, 2, 4, 7, 9, 12, 15, 17, 19, 25);
+ int found = ArrayUtils.binarySearch(list, 9, Data::getValue,
Integer::compare);
+ assertEquals(5, found);
+ }
+
+ @Test
+ public void binarySearch_whenNotExists_returnMinusInsertion() {
+ Data[] list = createList(0, 1, 2, 4, 7, 9, 12, 15, 17, 19, 25);
+ int found = ArrayUtils.binarySearch(list, 8, Data::getValue,
Integer::compare);
+ assertEquals(-6, found);
+ }
+
+ @Test
+ public void binarySearch_whenNotExistsBeginning_returnMinus1() {
+ Data[] list = createList(0, 1, 2, 4, 7, 9, 12, 15, 17, 19, 25);
+ int found = ArrayUtils.binarySearch(list, -3, Data::getValue,
Integer::compare);
+ assertEquals(-1, found);
+ }
+
+ @Test
+ public void binarySearch_whenNotExistsEnd_returnMinusLength() {
+ Data[] list = createList(0, 1, 2, 4, 7, 9, 12, 15, 17, 19, 25);
Review Comment:
Use `final` where you can.
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