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Checking if an array is sorted in java (#7385) 

* SortedArrayChecker

* add recursivity method with custom object

* change test names

* add new case with comparator

* update methods with comparable param

* format

* fix test

* change sign by comparable

* change employee by object. Rename method
This commit is contained in:
Carlos Cano 2019-07-25 21:09:02 +02:00 committed by maibin
parent 2c53cdd44e
commit 0d7a1747cc
2 changed files with 34 additions and 34 deletions
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38
core-java-modules/core-java-arrays/src/main/java/com/baeldung/array/SortedArrayChecker.java
View File

@ -2,7 +2,10 @@ package com.baeldung.array;
import com.baeldung.arraycopy.model.Employee;
import java.util.Comparator;
public class SortedArrayChecker {
boolean isSorted(int[] array, int length) {
if (array == null || length < 2)
return true;
@ -22,7 +25,7 @@ public class SortedArrayChecker {
return true;
}
boolean isSorted(String[] array, int length) {
boolean isSorted(Comparable[] array, int length) {
if (array == null || length < 2)
return true;
@ -32,40 +35,31 @@ public class SortedArrayChecker {
return isSorted(array, length - 1);
}
boolean isSorted(String[] array) {
for (int i = 0; i < array.length - 1; ++i) {
if (array[i].compareTo(array[i + 1]) > 0)
return false;
}
return true;
}
boolean isSortedByName(Employee[] array) {
boolean isSorted(Comparable[] array) {
for (int i = 0; i < array.length - 1; ++i) {
if (array[i].getName().compareTo(array[i + 1].getName()) > 0)
if (array[i].compareTo(array[i + 1]) > 0)
return false;
}
return true;
}
boolean isSortedByAge(Employee[] array) {
for (int i = 0; i < array.length - 1; ++i) {
if (array[i].getAge() > (array[i + 1].getAge()))
return false;
boolean isSorted(Object[] array, Comparator comparator) {
for (int i = 0; i < array.length - 1; ++i) {
if (comparator.compare(array[i], (array[i + 1])) > 0)
return false;
}
return true;
}
return true;
}
boolean isSortedByAge(Employee[] array, int length) {
boolean isSorted(Object[] array, Comparator comparator, int length) {
if (array == null || length < 2)
return true;
if (array[length - 2].getAge() > array[length - 1].getAge())
if (comparator.compare(array[length - 2], array[length - 1]) > 0)
return false;
return isSortedByAge(array, length - 1);
return isSorted(array, comparator, length - 1);
}
}

30
core-java-modules/core-java-arrays/src/test/java/com/baeldung/array/SortedArrayCheckerUnitTest.java
View File

@ -4,32 +4,33 @@ import com.baeldung.arraycopy.model.Employee;
import org.junit.Before;
import org.junit.Test;
import java.util.Comparator;
import static org.assertj.core.api.Assertions.assertThat;
class SortedArrayCheckerUnitTest {
public class SortedArrayCheckerUnitTest {
private static final int[] INTEGER_SORTED = {1, 3, 5, 7, 9};
private static final int[] INTEGER_NOT_SORTED = {1, 3, 11, 7};
private static final String[] STRING_SORTED = {"abc", "cde", "fgh"};
private static final String[] STRING_NOT_SORTED = {"abc", "fgh", "cde", "ijk"};
private final Employee[] EMPLOYEES_SORTED_BY_NAME = {
private static final Employee[] EMPLOYEES_SORTED_BY_NAME = {
new Employee(1, "Carlos", 26),
new Employee(2, "Daniel", 31),
new Employee(3, "Marta", 27)};
private final Employee[] EMPLOYEES_NOT_SORTED_BY_NAME = {
private static final Employee[] EMPLOYEES_NOT_SORTED_BY_NAME = {
new Employee(1, "Daniel", 31),
new Employee(2, "Carlos", 26),
new Employee(3, "Marta", 27)};
private final Employee[] EMPLOYEES_SORTED_BY_AGE = {
private static final Employee[] EMPLOYEES_SORTED_BY_AGE = {
new Employee(1, "Carlos", 26),
new Employee(2, "Marta", 27),
new Employee(3, "Daniel", 31)};
private final Employee[] EMPLOYEES_NOT_SORTED_BY_AGE = {
private static final Employee[] EMPLOYEES_NOT_SORTED_BY_AGE = {
new Employee(1, "Marta", 27),
new Employee(2, "Carlos", 26),
new Employee(3, "Daniel", 31)};
@ -61,13 +62,18 @@ class SortedArrayCheckerUnitTest {
@Test
public void givenEmployeeArray_thenReturnIfItIsSortedOrNot() {
assertThat(sortedArrayChecker.isSortedByName(EMPLOYEES_SORTED_BY_NAME)).isEqualTo(true);
assertThat(sortedArrayChecker.isSortedByName(EMPLOYEES_NOT_SORTED_BY_NAME)).isEqualTo(false);
assertThat(sortedArrayChecker.isSorted(EMPLOYEES_SORTED_BY_NAME, Comparator.comparing(Employee::getName))).isEqualTo(true);
assertThat(sortedArrayChecker.isSorted(EMPLOYEES_NOT_SORTED_BY_NAME, Comparator.comparing(Employee::getName))).isEqualTo(false);
assertThat(sortedArrayChecker.isSortedByAge(EMPLOYEES_SORTED_BY_AGE)).isEqualTo(true);
assertThat(sortedArrayChecker.isSortedByAge(EMPLOYEES_NOT_SORTED_BY_AGE)).isEqualTo(false);
assertThat(sortedArrayChecker.isSorted(EMPLOYEES_SORTED_BY_AGE, Comparator.comparingInt(Employee::getAge))).isEqualTo(true);
assertThat(sortedArrayChecker.isSorted(EMPLOYEES_NOT_SORTED_BY_AGE, Comparator.comparingInt(Employee::getAge))).isEqualTo(false);
assertThat(sortedArrayChecker.isSortedByAge(EMPLOYEES_SORTED_BY_AGE, EMPLOYEES_SORTED_BY_AGE.length)).isEqualTo(true);
assertThat(sortedArrayChecker.isSortedByAge(EMPLOYEES_NOT_SORTED_BY_AGE, EMPLOYEES_NOT_SORTED_BY_AGE.length)).isEqualTo(false);
assertThat(sortedArrayChecker
.isSorted(EMPLOYEES_SORTED_BY_AGE, Comparator.comparingInt(Employee::getAge), EMPLOYEES_SORTED_BY_AGE.length))
.isEqualTo(true);
assertThat(sortedArrayChecker
.isSorted(EMPLOYEES_NOT_SORTED_BY_AGE, Comparator.comparingInt(Employee::getAge), EMPLOYEES_NOT_SORTED_BY_AGE.length))
.isEqualTo(false);
}
}