From a5e2357033cd5f14f31a226139dd2becd2628219 Mon Sep 17 00:00:00 2001 From: Ahmed Tawila Date: Tue, 24 Oct 2017 18:47:40 +0200 Subject: [PATCH] BAEL-1250 Initializing Arrays in Java (#2811) * Evaluation article: Different Types of Bean Injection in Spring * added tests & changed configuration to Java-based config * removed xml config files * rename unit tests * BAEL-972 - Apache Commons Text * remove code from evaluation article * remove code from evaluation article * BAEL-972 - Apache Commons Text - added another example * BAEL-972 - Apache Commons Text - just indentation * BAEL-994 - TemporalAdjuster in Java * BAEL-994 - TemporalAdjuster in Java * BAEL-994 - TemporalAdjuster in Java * BAEL-994 - TemporalAdjuster in Java * BAEL-994 - TemporalAdjuster in Java - fix problems * BAEL-1033 Introduction to StreamUtils * BAEL-1033 Introduction to StreamUtils * BAEL-1033 Introduction to StreamUtils * fix formatting * BAEL-1033 minor refactor * BAEL-1035 Introduction to Eclipse Collections * format * BAEL-1035 Introduction to Eclipse Collections * BAEL-1035 Introduction to Eclipse Collections * BAEL-1035 Introduction to Eclipse Collections * cleanup * cleanup * BAEL-1109 Introduction to JCache * BAEL-1109 Introduction to JCache * remove unneeded property in pom.xml * fix formatting * close cache instances properly * remove latest commit * BAEL-1057 Introduction to rxjava-jdbc * refactor rxjava-jdbc * Refactor rxjava-jdbc * Refactoring rxjava-jdbc * BAEL-1171 java.lang.String API * refactor rxjava-jdbc * refactor String * String API - move multiple classes into a single class * move class into test package * BAEL-1171 String.lang.String API * BAEL-1171 java.lang.String API * BAEL-1250 Initializing Arrays in Java * BAEL-1250 Initializing Arrays in Java --- .../com/baeldung/array/ArrayInitializer.java | 74 +++++++++++++++++++ .../baeldung/array/ArrayInitializerTest.java | 68 +++++++++++++++++ 2 files changed, 142 insertions(+) create mode 100644 core-java/src/main/java/com/baeldung/array/ArrayInitializer.java create mode 100644 core-java/src/test/java/com/baeldung/array/ArrayInitializerTest.java diff --git a/core-java/src/main/java/com/baeldung/array/ArrayInitializer.java b/core-java/src/main/java/com/baeldung/array/ArrayInitializer.java new file mode 100644 index 0000000000..fd00c74e7f --- /dev/null +++ b/core-java/src/main/java/com/baeldung/array/ArrayInitializer.java @@ -0,0 +1,74 @@ +package com.baeldung.array; + +import java.util.Arrays; + +public class ArrayInitializer { + + public static int[] initializeArrayInLoop() { + int array[] = new int[5]; + for (int i = 0; i < array.length; i++) + array[i] = i + 2; + return array; + } + + public static int[][] initializeMultiDimensionalArrayInLoop() { + int array[][] = new int[2][5]; + for (int i = 0; i < 2; i++) + for (int j = 0; j < 5; j++) + array[i][j] = j + 1; + return array; + } + + public static String[] initializeArrayAtTimeOfDeclarationMethod1() { + String array[] = new String[] { "Toyota", "Mercedes", "BMW", "Volkswagen", "Skoda" }; + return array; + } + + public static int[] initializeArrayAtTimeOfDeclarationMethod2() { + int[] array = new int[] { 1, 2, 3, 4, 5 }; + return array; + } + + public static int[] initializeArrayAtTimeOfDeclarationMethod3() { + int array[] = { 1, 2, 3, 4, 5 }; + return array; + } + + public static long[] initializeArrayUsingArraysFill() { + long array[] = new long[5]; + Arrays.fill(array, 30); + return array; + } + + public static int[] initializeArrayRangeUsingArraysFill() { + int array[] = new int[5]; + Arrays.fill(array, 0, 3, -50); + return array; + } + + public static int[] initializeArrayUsingArraysCopy() { + int array[] = { 1, 2, 3, 4, 5 }; + int[] copy = Arrays.copyOf(array, 5); + return copy; + } + + public static int[] initializeLargerArrayUsingArraysCopy() { + int array[] = { 1, 2, 3, 4, 5 }; + int[] copy = Arrays.copyOf(array, 6); + return copy; + } + + public static int[] initializeArrayUsingArraysSetAll() { + int[] array = new int[20]; + + for (int i = 0; i < 20; i++) { + Arrays.setAll(array, p -> { + if (p > 9) + return 0; + else + return p; + }); + } + return array; + } +} diff --git a/core-java/src/test/java/com/baeldung/array/ArrayInitializerTest.java b/core-java/src/test/java/com/baeldung/array/ArrayInitializerTest.java new file mode 100644 index 0000000000..d3afad7b00 --- /dev/null +++ b/core-java/src/test/java/com/baeldung/array/ArrayInitializerTest.java @@ -0,0 +1,68 @@ +package com.baeldung.array; + +import static com.baeldung.array.ArrayInitializer.initializeArrayAtTimeOfDeclarationMethod1; +import static com.baeldung.array.ArrayInitializer.initializeArrayAtTimeOfDeclarationMethod2; +import static com.baeldung.array.ArrayInitializer.initializeArrayAtTimeOfDeclarationMethod3; +import static com.baeldung.array.ArrayInitializer.initializeArrayInLoop; +import static com.baeldung.array.ArrayInitializer.initializeArrayRangeUsingArraysFill; +import static com.baeldung.array.ArrayInitializer.initializeArrayUsingArraysCopy; +import static com.baeldung.array.ArrayInitializer.initializeArrayUsingArraysFill; +import static com.baeldung.array.ArrayInitializer.initializeArrayUsingArraysSetAll; +import static com.baeldung.array.ArrayInitializer.initializeLargerArrayUsingArraysCopy; +import static com.baeldung.array.ArrayInitializer.initializeMultiDimensionalArrayInLoop; +import static org.junit.Assert.assertArrayEquals; + +import org.junit.Test; + +public class ArrayInitializerTest { + + @Test + public void whenInitializeArrayInLoop_thenCorrect() { + assertArrayEquals(new int[] { 2, 3, 4, 5, 6 }, initializeArrayInLoop()); + } + + @Test + public void whenInitializeMultiDimensionalArrayInLoop_thenCorrect() { + assertArrayEquals(new int[][] { { 1, 2, 3, 4, 5 }, { 1, 2, 3, 4, 5 } }, initializeMultiDimensionalArrayInLoop()); + } + + @Test + public void whenInitializeArrayAtTimeOfDeclarationMethod1_thenCorrect() { + assertArrayEquals(new String[] { "Toyota", "Mercedes", "BMW", "Volkswagen", "Skoda" }, initializeArrayAtTimeOfDeclarationMethod1()); + } + + @Test + public void whenInitializeArrayAtTimeOfDeclarationMethod2_thenCorrect() { + assertArrayEquals(new int[] { 1, 2, 3, 4, 5 }, initializeArrayAtTimeOfDeclarationMethod2()); + } + + @Test + public void whenInitializeArrayAtTimeOfDeclarationMethod3_thenCorrect() { + assertArrayEquals(new int[] { 1, 2, 3, 4, 5 }, initializeArrayAtTimeOfDeclarationMethod3()); + } + + @Test + public void whenInitializeArrayUsingArraysFill_thenCorrect() { + assertArrayEquals(new long[] { 30, 30, 30, 30, 30 }, initializeArrayUsingArraysFill()); + } + + @Test + public void whenInitializeArrayRangeUsingArraysFill_thenCorrect() { + assertArrayEquals(new int[] { -50, -50, -50, 0, 0 }, initializeArrayRangeUsingArraysFill()); + } + + @Test + public void whenInitializeArrayRangeUsingArraysCopy_thenCorrect() { + assertArrayEquals(new int[] { 1, 2, 3, 4, 5 }, initializeArrayUsingArraysCopy()); + } + + @Test + public void whenInitializeLargerArrayRangeUsingArraysCopy_thenCorrect() { + assertArrayEquals(new int[] { 1, 2, 3, 4, 5, 0 }, initializeLargerArrayUsingArraysCopy()); + } + + @Test + public void whenInitializeLargerArrayRangeUsingArraysSetAll_thenCorrect() { + assertArrayEquals(new int[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, initializeArrayUsingArraysSetAll()); + } +}