iSharkFly-Docs
/
java-tutorials
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Initial commit for lazy lambda article

This commit is contained in:
maenolis 2023-11-15 08:33:33 +02:00
parent 7c1065b494
commit 7135047ba1
7 changed files with 147 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
core-java-modules/core-java-21/pom.xml
View File

@ -22,9 +22,7 @@
<target>21</target>
<!-- Needed due to a bug with JDK 21, described here: https://issues.apache.org/jira/browse/MCOMPILER-546?page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel&focusedCommentId=17767513 -->
<debug>false</debug>
<compilerArgs>
<arg>--enable-preview</arg>
</compilerArgs>
<compilerArgs>--enable-preview</compilerArgs>
</configuration>
</plugin>
<plugin>
@ -38,6 +36,15 @@
</plugins>
</build>
<dependencies>
<dependency>
<groupId>org.mockito</groupId>
<artifactId>mockito-core</artifactId>
<version>5.7.0</version>
<scope>test</scope>
</dependency>
</dependencies>
<properties>
<maven.compiler.source.version>21</maven.compiler.source.version>
<maven.compiler.target.version>21</maven.compiler.target.version>

16
core-java-modules/core-java-21/src/main/java/com/baeldung/lazylambda/LambdaSupplier.java Normal file
View File

@ -0,0 +1,16 @@
package com.baeldung.lazylambda;
import java.util.function.Supplier;
public class LambdaSupplier<T> {
private final Supplier<T> expensiveData;
public LambdaSupplier(Supplier<T> expensiveData) {
this.expensiveData = expensiveData;
}
public T getData() {
return expensiveData.get();
}
}

22
core-java-modules/core-java-21/src/main/java/com/baeldung/lazylambda/LazyLambdaSupplier.java Normal file
View File

@ -0,0 +1,22 @@
package com.baeldung.lazylambda;
import java.util.function.Supplier;
public class LazyLambdaSupplier<T> {
private final Supplier<T> expensiveData;
private T data;
public LazyLambdaSupplier(Supplier<T> expensiveData) {
this.expensiveData = expensiveData;
}
public T getData() {
if (data != null) {
return data;
}
return data = expensiveData.get();
}
}

29
core-java-modules/core-java-21/src/main/java/com/baeldung/lazylambda/LazyLambdaThreadSafeSupplier.java Normal file
View File

@ -0,0 +1,29 @@
package com.baeldung.lazylambda;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Supplier;
public class LazyLambdaThreadSafeSupplier<T> {
private final Supplier<T> expensiveData;
private final AtomicReference<T> data;
public LazyLambdaThreadSafeSupplier(Supplier<T> expensiveData) {
this.expensiveData = expensiveData;
data = new AtomicReference<>();
}
public T getData() {
if (data.get() == null) {
synchronized (data) {
if (data.get() == null) {
data.set(expensiveData.get());
}
}
}
return data.get();
}
}

24
core-java-modules/core-java-21/src/test/java/com/baeldung/lazylambda/LambdaSupplierUnitTest.java Normal file
View File

@ -0,0 +1,24 @@
package com.baeldung.lazylambda;
import java.util.function.Supplier;
import org.junit.Test;
import org.mockito.Mockito;
public class LambdaSupplierUnitTest {
@Test
public void whenCalledMultipleTimes_thenShouldBeCalledMultipleTimes() {
@SuppressWarnings("unchecked")
Supplier<String> mockedExpensiveFunction = Mockito.mock(Supplier.class);
Mockito.when(mockedExpensiveFunction.get()).thenReturn("expensive call");
LambdaSupplier<String> testee = new LambdaSupplier<>(mockedExpensiveFunction);
Mockito.verify(mockedExpensiveFunction, Mockito.never()).get();
testee.getData();
testee.getData();
testee.getData();
testee.getData();
Mockito.verify(mockedExpensiveFunction, Mockito.times(4)).get();
}
}

23
core-java-modules/core-java-21/src/test/java/com/baeldung/lazylambda/LazyLambdaSupplierUnitTest.java Normal file
View File

@ -0,0 +1,23 @@
package com.baeldung.lazylambda;
import java.util.function.Supplier;
import org.junit.Test;
import org.mockito.Mockito;
public class LazyLambdaSupplierUnitTest {
@Test
public void whenCalledMultipleTimes_thenShouldBeCalledOnlyOnce() {
@SuppressWarnings("unchecked") Supplier<String> mockedExpensiveFunction = Mockito.mock(Supplier.class);
Mockito.when(mockedExpensiveFunction.get()).thenReturn("expensive call");
LazyLambdaSupplier<String> testee = new LazyLambdaSupplier<>(mockedExpensiveFunction);
Mockito.verify(mockedExpensiveFunction, Mockito.never()).get();
testee.getData();
testee.getData();
testee.getData();
testee.getData();
Mockito.verify(mockedExpensiveFunction, Mockito.times(1)).get();
}
}

23
core-java-modules/core-java-21/src/test/java/com/baeldung/lazylambda/LazyLambdaThreadSafeSupplierUnitTest.java Normal file
View File

@ -0,0 +1,23 @@
package com.baeldung.lazylambda;
import java.util.function.Supplier;
import org.junit.Test;
import org.mockito.Mockito;
public class LazyLambdaThreadSafeSupplierUnitTest {
@Test
public void whenCalledMultipleTimes_thenShouldBeCalledOnlyOnce() {
@SuppressWarnings("unchecked") Supplier<String> mockedExpensiveFunction = Mockito.mock(Supplier.class);
Mockito.when(mockedExpensiveFunction.get()).thenReturn("expensive call");
LazyLambdaThreadSafeSupplier<String> testee = new LazyLambdaThreadSafeSupplier<>(mockedExpensiveFunction);
Mockito.verify(mockedExpensiveFunction, Mockito.never()).get();
testee.getData();
testee.getData();
testee.getData();
testee.getData();
Mockito.verify(mockedExpensiveFunction, Mockito.times(1)).get();
}
}