Add adapter implementation with unit test (#45)

Author: mperor

DesignPatterns/src/main/java/pl/mperor/lab/java/design/pattern/structural/adapter/AnalogSignal.java

@@ -0,0 +1,7 @@
+package pl.mperor.lab.java.design.pattern.structural.adapter;
+
+@FunctionalInterface
+public interface AnalogSignal {
+
+    void transmitAnalog();
+}

DesignPatterns/src/main/java/pl/mperor/lab/java/design/pattern/structural/adapter/ComputerMonitor.java

@@ -0,0 +1,9 @@
+package pl.mperor.lab.java.design.pattern.structural.adapter;
+
+public record ComputerMonitor() {
+
+    void display(AnalogSignal analogSignal) {
+        System.out.println("🖥️ Computer monitor displaying ...");
+        analogSignal.transmitAnalog();
+    }
+}

DesignPatterns/src/main/java/pl/mperor/lab/java/design/pattern/structural/adapter/DigitalSignal.java

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+package pl.mperor.lab.java.design.pattern.structural.adapter;
+
+@FunctionalInterface
+public interface DigitalSignal {
+
+    void transmitDigital();
+}

DesignPatterns/src/main/java/pl/mperor/lab/java/design/pattern/structural/adapter/DigitalToAnalogSignalAdapter.java

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+package pl.mperor.lab.java.design.pattern.structural.adapter;
+
+public class DigitalToAnalogSignalAdapter implements AnalogSignal {
+
+    private final DigitalSignal digitalSignal;
+
+    public DigitalToAnalogSignalAdapter(DigitalSignal digitalSignal) {
+        this.digitalSignal = digitalSignal;
+    }
+
+    @Override
+    public void transmitAnalog() {
+        digitalSignal.transmitDigital();
+    }
+}

DesignPatterns/src/main/java/pl/mperor/lab/java/design/pattern/structural/adapter/VideoCard.java

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+package pl.mperor.lab.java.design.pattern.structural.adapter;
+
+import java.util.function.Consumer;
+
+public record VideoCard() {
+
+    public void render(Consumer<DigitalSignal> consumer) {
+        DigitalSignal renderedSignal = () -> System.out.println("Video card rendered signal 🎲");
+        consumer.accept(renderedSignal);
+    }
+}

DesignPatterns/src/test/java/pl/mperor/lab/java/design/pattern/structural/adapter/DigitalToAnalogSignalAdapterTest.java

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+package pl.mperor.lab.java.design.pattern.structural.adapter;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import pl.mperor.lab.common.TestUtils;
+
+public class DigitalToAnalogSignalAdapterTest {
+
+    @Test
+    public void adapterShouldAllowToTransformDigitalSignalToAnalogSignal() {
+        var out = TestUtils.setTempSystemOut();
+
+        var monitor = new ComputerMonitor();
+        var videoCard = new VideoCard();
+
+        videoCard.render(digitalSignal ->
+                monitor.display(new DigitalToAnalogSignalAdapter(digitalSignal))
+        );
+
+        var outLines = out.lines();
+        Assertions.assertEquals("🖥️ Computer monitor displaying ...", outLines.getFirst());
+        Assertions.assertEquals("Video card rendered signal 🎲", outLines.getSecond());
+
+        TestUtils.resetSystemOut();
+    }
+
+}