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[chk-double-is-int] check if doulbe is integer (#15312)

This commit is contained in:
Kai Yuan 2023-12-03 17:55:52 +01:00 committed by GitHub
parent 1bae3d7580
commit 7f1bfe6a87
3 changed files with 121 additions and 1 deletions
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37
core-java-modules/core-java-numbers-7/pom.xml Normal file
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@ -0,0 +1,37 @@
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>core-java-numbers-7</artifactId>
<name>core-java-numbers-7</name>
<packaging>jar</packaging>
<parent>
<groupId>com.baeldung.core-java-modules</groupId>
<artifactId>core-java-modules</artifactId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<dependencies>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-engine</artifactId>
<version>${junit-jupiter.version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>${guava.version}</version>
</dependency>
</dependencies>
<build>
<finalName>core-java-numbers-7</finalName>
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
</build>
</project>

83
core-java-modules/core-java-numbers-7/src/test/java/com/baeldung/doubleisint/CheckDoubleIsAnIntegerUnitTest.java Normal file
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@ -0,0 +1,83 @@
package com.baeldung.doubleisint;
import com.google.common.math.DoubleMath;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertTrue;
public class CheckDoubleIsAnIntegerUnitTest {
boolean notNaNOrInfinity(double d) {
return !(Double.isNaN(d) || Double.isInfinite(d));
}
@Test
void whenConvertingToInt_thenGetExpectedResult() {
double d1 = 42.0D;
boolean d1IsInteger = notNaNOrInfinity(d1) && (int) d1 == d1;
assertTrue(d1IsInteger);
double d2 = 42.42D;
boolean d2IsInteger = notNaNOrInfinity(d2) && (int) d2 == d2;
assertFalse(d2IsInteger);
double d3 = 2.0D * Integer.MAX_VALUE;
boolean d3IsInteger = notNaNOrInfinity(d3) && (int) d3 == d3;
assertTrue(!d3IsInteger); // <-- fails if exceeding Integer's range
}
@Test
void whenUsingModuloOperator_thenGetExpectedResult() {
double d1 = 42.0D;
boolean d1IsInteger = notNaNOrInfinity(d1) && (d1 % 1) == 0;
assertTrue(d1IsInteger);
double d2 = 42.42D;
boolean d2IsInteger = notNaNOrInfinity(d2) && (d2 % 1) == 0;
assertFalse(d2IsInteger);
double d3 = 2.0D * Integer.MAX_VALUE;
boolean d3IsInteger = notNaNOrInfinity(d3) && (d3 % 1) == 0;
assertTrue(d3IsInteger);
}
@Test
void whenCheckingFloorOrCeilingValue_thenGetExpectedResult() {
double d1 = 42.0D;
boolean d1IsInteger = notNaNOrInfinity(d1) && Math.floor(d1) == d1;
assertTrue(d1IsInteger);
double d2 = 42.42D;
boolean d2IsInteger = notNaNOrInfinity(d2) && Math.floor(d2) == d2;
assertFalse(d2IsInteger);
double d3 = 2.0D * Integer.MAX_VALUE;
boolean d3IsInteger = notNaNOrInfinity(d3) && Math.floor(d3) == d3;
assertTrue(d3IsInteger);
}
@Test
void whenUsingGuava_thenGetExpectedResult() {
double d1 = 42.0D;
boolean d1IsInteger = DoubleMath.isMathematicalInteger(d1);
assertTrue(d1IsInteger);
double d2 = 42.42D;
boolean d2IsInteger = DoubleMath.isMathematicalInteger(d2);
assertFalse(d2IsInteger);
double d3 = 2.0D * Integer.MAX_VALUE;
boolean d3IsInteger = DoubleMath.isMathematicalInteger(d3);
assertTrue(d3IsInteger);
boolean isInfinityInt = DoubleMath.isMathematicalInteger(Double.POSITIVE_INFINITY);
assertFalse(isInfinityInt);
boolean isNanInt = DoubleMath.isMathematicalInteger(Double.NaN);
assertFalse(isNanInt);
}
}

2
core-java-modules/pom.xml
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@ -166,6 +166,7 @@
<module>core-java-numbers-4</module>
<module>core-java-numbers-5</module>
<module>core-java-numbers-6</module>
<module>core-java-numbers-7</module>
<module>core-java-optional</module>
<module>core-java-perf</module>
<module>core-java-properties</module>
@ -225,5 +226,4 @@
</dependency>
</dependencies>
</dependencyManagement>
</project>