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BAEL2489 Avoid check for null statement in Java

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This commit is contained in:
Chirag Dewan 2019-03-16 11:35:29 +05:30
parent 37d4b5d643
commit b1a4f6bb21
12 changed files with 221 additions and 59 deletions
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26
core-java/pom.xml
View File

@ -216,8 +216,7 @@
<configuration>
<shadedArtifactAttached>true</shadedArtifactAttached>
<transformers>
<transformer
implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
</transformer>
</transformers>
@ -272,7 +271,7 @@
<argument>-Xmx300m</argument>
<argument>-XX:+UseParallelGC</argument>
<argument>-classpath</argument>
<classpath/>
<classpath />
<argument>com.baeldung.outofmemoryerror.OutOfMemoryGCLimitExceed</argument>
</arguments>
</configuration>
@ -338,7 +337,7 @@
<executable>java</executable>
<arguments>
<argument>-classpath</argument>
<classpath/>
<classpath />
<argument>org.openjdk.jmh.Main</argument>
<argument>.*</argument>
</arguments>
@ -371,8 +370,7 @@
<manifest>
<addClasspath>true</addClasspath>
</manifest>
<manifestFile>${project.build.outputDirectory}/META-INF/MANIFEST.MF
</manifestFile>
<manifestFile>${project.build.outputDirectory}/META-INF/MANIFEST.MF</manifestFile>
</archive>
<includes>
@ -406,14 +404,12 @@
<manifest>
<addClasspath>true</addClasspath>
</manifest>
<manifestFile>${project.build.outputDirectory}/META-INF/MANIFEST.MF
</manifestFile>
<manifestFile>${project.build.outputDirectory}/META-INF/MANIFEST.MF</manifestFile>
</archive>
<includes>
<include>com/baeldung/instrumentation/application/MyAtm.class</include>
<include>com/baeldung/instrumentation/application/MyAtmApplication.class
</include>
<include>com/baeldung/instrumentation/application/MyAtmApplication.class</include>
<include>com/baeldung/instrumentation/application/Launcher.class</include>
</includes>
</configuration>
@ -443,14 +439,12 @@
<manifest>
<addClasspath>true</addClasspath>
</manifest>
<manifestFile>${project.build.outputDirectory}/META-INF/MANIFEST.MF
</manifestFile>
<manifestFile>${project.build.outputDirectory}/META-INF/MANIFEST.MF</manifestFile>
</archive>
<includes>
<include>com/baeldung/instrumentation/agent/AtmTransformer.class</include>
<include>com/baeldung/instrumentation/agent/MyInstrumentationAgent.class
</include>
<include>com/baeldung/instrumentation/agent/MyInstrumentationAgent.class</include>
</includes>
</configuration>
</execution>
@ -462,7 +456,6 @@
</profiles>
<properties>
<!-- marshalling -->
<gson.version>2.8.2</gson.version>
@ -483,12 +476,10 @@
<!-- maven plugins -->
<maven-surefire-plugin.version>2.21.0</maven-surefire-plugin.version>
<javamoney.moneta.version>1.1</javamoney.moneta.version>
<h2database.version>1.4.197</h2database.version>
<esapi.version>2.1.0.1</esapi.version>
<jmh-core.version>1.19</jmh-core.version>
<jmh-generator-annprocess.version>1.19</jmh-generator-annprocess.version>
<maven-javadoc-plugin.version>3.0.0-M1</maven-javadoc-plugin.version>
<maven-jar-plugin.version>3.0.2</maven-jar-plugin.version>
@ -499,7 +490,6 @@
<icu4j.version>61.1</icu4j.version>
<!-- instrumentation -->
<javaassist.version>3.21.0-GA</javaassist.version>
<sun.tools.version>1.8.0</sun.tools.version>
<intellij.annotations.version>16.0.2</intellij.annotations.version>
</properties>

7
core-java/src/main/java/com/baeldung/nulls/APIContracts.java
View File

@ -4,6 +4,7 @@ public class APIContracts {
/**
* Prints the value of {@code param} if not null. Prints {@code null} otherwise.
*
* @param param
*/
public void print(Object param) {
@ -11,17 +12,17 @@ public class APIContracts {
}
/**
*
* @return non null result
* @throws Exception - if result is null
*/
public Object process() throws Exception {
Object result = doSomething();
if (result == null)
if (result == null) {
throw new Exception("Processing fail. Got a null response");
else
} else {
return result;
}
}
private Object doSomething() {
return null;

15
core-java/src/main/java/com/baeldung/nulls/Preconditions.java
View File

@ -3,22 +3,26 @@ package com.baeldung.nulls;
public class Preconditions {
public void goodAccept(String one, String two, String three) {
if (null == one || null == two || three == null)
if (one == null || two == null || three == null)
throw new IllegalArgumentException();
process(one);
process(two);
process(three);
}
public void badAccept(String one, String two, String three){
if (null == one)
public void badAccept(String one, String two, String three) {
if (one == null)
throw new IllegalArgumentException();
else
process(one);
if (null == two)
if (two == null)
throw new IllegalArgumentException();
else
process(two);
if (null == three)
if (three == null)
throw new IllegalArgumentException();
else
process(three);
@ -28,5 +32,4 @@ public class Preconditions {
private void process(String one) {
}
}

8
core-java/src/main/java/com/baeldung/nulls/PrimitivesAndWrapper.java
View File

@ -2,11 +2,11 @@ package com.baeldung.nulls;
public class PrimitivesAndWrapper {
public static int sum(int a, int b) {
public static int primitiveSum(int a, int b) {
return a + b;
}
public static Integer sum(Integer a, Integer b) {
public static Integer wrapperSum(Integer a, Integer b) {
return a + b;
}
@ -17,8 +17,4 @@ public class PrimitivesAndWrapper {
throw new IllegalArgumentException();
}
public static void main(String[] args) {
sum(0, 0);
sum(null, null);
}
}

16
core-java/src/main/java/com/baeldung/nulls/UsingObjects.java
View File

@ -4,21 +4,13 @@ import java.util.Objects;
public class UsingObjects {
private String checked;
public void accept(Object param) {
public void accept(Object param) throws Exception {
try {
Objects.requireNonNull(param);
} catch (NullPointerException e) {
//doSomethingElseToo
e.printStackTrace();
}
}
public void caller() throws Exception {
if (Objects.nonNull(checked))
accept(checked);
else
throw new Exception();
}
//doSomething()
}
}

24
core-java/src/main/java/com/baeldung/nulls/UsingOptional.java
View File

@ -4,20 +4,24 @@ import java.util.Optional;
public class UsingOptional {
public Optional<Object> process() {
if (isProcessed())
return Optional.of("dummy");
else
public Optional<Object> process(boolean processed) {
String response = doSomething(processed);
if (response == null) {
return Optional.empty();
}
public void caller() {
Optional<Object> result = process();
result.ifPresent(p -> System.out.println(p));
result.orElseThrow(() -> new IllegalArgumentException());
return Optional.of(response);
}
private boolean isProcessed() {
return false;
private String doSomething(boolean processed) {
if (processed) {
return "passed";
} else {
return null;
}
}
}

11
core-java/src/main/java/com/baeldung/nulls/UsingStringUtils.java
View File

@ -1,17 +1,22 @@
package com.baeldung.nulls;
import org.apache.commons.lang3.StringUtils;
public class UsingStringUtils {
public void accept(String param) {
if (StringUtils.isNotEmpty(param))
if (StringUtils.isNotEmpty(param)) {
System.out.println(param);
} else {
throw new IllegalArgumentException();
}
}
public void acceptOnlyNonBlank(String param) {
if (StringUtils.isNotBlank(param))
if (StringUtils.isNotBlank(param)) {
System.out.println(param);
} else {
throw new IllegalArgumentException();
}
}
}

35
core-java/src/test/java/com/baeldung/nulls/PrimitivesAndWrapperTest.java Normal file
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@ -0,0 +1,35 @@
package com.baeldung.nulls;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
import org.junit.jupiter.api.Test;
class PrimitivesAndWrapperTest {
@Test
public void givenWrappers_whenBothArgsNonNull_thenReturnResult() {
Integer sum = PrimitivesAndWrapper.wrapperSum(0, 0);
assertEquals(0, sum.intValue());
}
@Test()
public void givenWrappers_whenOneArgIsNull_thenThrowNullPointerException() {
assertThrows(NullPointerException.class, () -> PrimitivesAndWrapper.wrapperSum(null, 2));
}
@Test()
public void givenWrappers_whenBothArgsAreNull_thenThrowNullPointerException() {
assertThrows(NullPointerException.class, () -> PrimitivesAndWrapper.wrapperSum(null, null));
}
@Test()
public void givenWrappersWithNullCheck_whenAnyArgIsNull_thenThrowIllegalArgumentException() {
assertThrows(IllegalArgumentException.class, () -> PrimitivesAndWrapper.goodSum(null, 2));
}
}

25
core-java/src/test/java/com/baeldung/nulls/UsingLombokTest.java Normal file
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@ -0,0 +1,25 @@
package com.baeldung.nulls;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
class UsingLombokTest {
private UsingLombok classUnderTest;
@BeforeEach
public void setup() {
classUnderTest = new UsingLombok();
}
@Test
public void whenNullArg_thenThrowNullPointerException() {
assertThrows(NullPointerException.class, () -> classUnderTest.accept(null));
}
}

31
core-java/src/test/java/com/baeldung/nulls/UsingObjectsTest.java Normal file
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@ -0,0 +1,31 @@
package com.baeldung.nulls;
import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
import static org.junit.jupiter.api.Assertions.assertThrows;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
class UsingObjectsTest {
private UsingObjects classUnderTest;
@BeforeEach
public void setup() {
classUnderTest = new UsingObjects();
}
@Test
public void whenArgIsNull_thenThrowException() {
assertThrows(Exception.class, () -> classUnderTest.accept(null));
}
@Test
public void whenArgIsNonNull_thenDoesNotThrowException() {
assertDoesNotThrow(() -> classUnderTest.accept("test "));
}
}

37
core-java/src/test/java/com/baeldung/nulls/UsingOptionalTest.java Normal file
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@ -0,0 +1,37 @@
package com.baeldung.nulls;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;
import java.util.Optional;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
class UsingOptionalTest {
private UsingOptional classUnderTest;
@BeforeEach
public void setup() {
classUnderTest = new UsingOptional();
}
@Test
public void whenArgIsFalse_thenReturnEmptyResponse() {
Optional<Object> result = classUnderTest.process(false);
assertFalse(result.isPresent());
}
@Test
public void whenArgIsTrue_thenReturnValidResponse() {
Optional<Object> result = classUnderTest.process(true);
assertTrue(result.isPresent());
}
@Test
public void whenArgIsFalse_thenChainResponseAndThrowException() {
assertThrows(Exception.class, () -> classUnderTest.process(false).orElseThrow(() -> new Exception()));
}
}

43
core-java/src/test/java/com/baeldung/nulls/UsingStringUtilsTest.java Normal file
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@ -0,0 +1,43 @@
package com.baeldung.nulls;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
class UsingStringUtilsTest {
private UsingStringUtils classUnderTest;
@BeforeEach
public void setup() {
classUnderTest = new UsingStringUtils();
}
@Test
public void givenAccept_whenArgIsNull_throwIllegalArgumentException() {
Assertions.assertThrows(IllegalArgumentException.class, () -> classUnderTest.accept(null));
}
@Test
public void givenAccept_whenArgIsEmpty_throwIllegalArgumentException() {
Assertions.assertThrows(IllegalArgumentException.class, () -> classUnderTest.accept(""));
}
@Test
public void givenAcceptOnlyNonBlank_whenArgIsNull_throwIllegalArgumentException() {
Assertions.assertThrows(IllegalArgumentException.class, () -> classUnderTest.acceptOnlyNonBlank(null));
}
@Test
public void givenAcceptOnlyNonBlank_whenArgIsEmpty_throwIllegalArgumentException() {
Assertions.assertThrows(IllegalArgumentException.class, () -> classUnderTest.acceptOnlyNonBlank(""));
}
@Test
public void givenAcceptOnlyNonBlank_whenArgIsBlank_throwIllegalArgumentException() {
Assertions.assertThrows(IllegalArgumentException.class, () -> classUnderTest.acceptOnlyNonBlank(" "));
}
}