feat: adds Trinitie's lesson_16 homework about custom data types (#567)

* feat: adds lesson_16 homework about Custom Data Types with all tests passed

* chore: adds/plays with more tests, constructors, functions, and variables

* chore: fixing startCall() to make more sense

Author: txjackson252

lesson_16/objects/objects_app/src/main/java/com/codedifferently/lesson16/trinitiejackson/CriticalBatteryException.java

@@ -0,0 +1,7 @@
+package com.codedifferently.lesson16.trinitiejackson;
+
+public class CriticalBatteryException extends RuntimeException {
+  public CriticalBatteryException(String message) {
+    super(message);
+  }
+}

lesson_16/objects/objects_app/src/main/java/com/codedifferently/lesson16/trinitiejackson/Phone.java

@@ -0,0 +1,92 @@
+package com.codedifferently.lesson16.trinitiejackson;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Phone {
+  private int batteryLevel;
+  private boolean isOn;
+  private boolean callInProgress;
+  private Volume currentVolume;
+  private final List<String> textReady;
+  private final String brand;
+
+  public Phone(int batteryLevel, List<String> textReady, String brand) {
+    this.batteryLevel = batteryLevel;
+    this.isOn = false;
+    this.callInProgress = false;
+    this.currentVolume = Volume.LOW;
+    this.textReady = new ArrayList<>(textReady);
+    this.brand = brand;
+  }
+
+  public boolean isOn() {
+    return isOn;
+  }
+
+  public int getBatteryLevel() {
+    return batteryLevel;
+  }
+
+  public String getBrand() {
+    return brand;
+  }
+
+  public boolean isCallInProgress() {
+    return callInProgress;
+  }
+
+  public Volume getCurrentVolume() {
+    return currentVolume;
+  }
+
+  public List<String> getTextReady() {
+    return new ArrayList<>(textReady);
+  }
+
+  public void powerOn() {
+    isOn = true;
+  }
+
+  public void powerOff() {
+    isOn = false;
+  }
+
+  public void setCurrentVolume(Volume volume) {
+    this.currentVolume = volume;
+  }
+
+  public boolean lowBattery() {
+    return batteryLevel < 21;
+  }
+
+  public void startCall() throws CriticalBatteryException {
+    if (batteryLevel <= 5) {
+      throw new CriticalBatteryException("Battery too low to start a call");
+    }
+
+    if (isOn && batteryLevel > 5) {
+      batteryLevel -= 2;
+      callInProgress = true;
+    } else {
+      callInProgress = false;
+    }
+  }
+
+  public String printAllVolumeSettings() {
+    StringBuilder sb = new StringBuilder();
+
+    for (Volume v : Volume.values()) {
+      if (sb.length() > 0) {
+        sb.append(", ");
+      }
+      sb.append(v.name());
+    }
+
+    return sb.toString();
+  }
+
+  public void addTextReady(String text) {
+    textReady.add(text);
+  }
+}

lesson_16/objects/objects_app/src/main/java/com/codedifferently/lesson16/trinitiejackson/Volume.java

@@ -0,0 +1,8 @@
+package com.codedifferently.lesson16.trinitiejackson;
+
+public enum Volume {
+  MUTE,
+  LOW,
+  MEDIUM,
+  HIGH
+}

lesson_16/objects/objects_app/src/test/java/com/codedifferently/trinitiejackson/PhoneTest.java

@@ -0,0 +1,106 @@
+package com.codedifferently.trinitiejackson;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import com.codedifferently.lesson16.trinitiejackson.CriticalBatteryException;
+import com.codedifferently.lesson16.trinitiejackson.Phone;
+import com.codedifferently.lesson16.trinitiejackson.Volume;
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class PhoneTest {
+  private Phone phone1;
+  private Phone phone2;
+
+  @BeforeEach
+  public void setUp() {
+    phone1 = new Phone(50, new ArrayList<>(List.of("Hello", "How are you?")), "Samsung");
+    phone2 = new Phone(2, new ArrayList<>(List.of("Goodbye", "Why?")), "Apple");
+  }
+
+  @Test
+  public void testIsOn() {
+    assertThat(phone1.isOn()).isFalse();
+  }
+
+  @Test
+  public void testPowerOn() {
+    phone1.powerOn();
+    assertThat(phone1.isOn()).isTrue();
+  }
+
+  @Test
+  public void testPowerOff() {
+    phone2.powerOff();
+    assertThat(phone2.isOn()).isFalse();
+  }
+
+  @Test
+  public void testGetBatteryLevel() {
+    assertThat(phone1.getBatteryLevel()).isEqualTo(50);
+  }
+
+  @Test
+  public void testLowBattery() {
+    assertThat(phone2.getBatteryLevel()).isLessThanOrEqualTo(21);
+    assertThat(phone2.lowBattery()).isTrue();
+  }
+
+  @Test
+  public void testGetBrand() {
+    assertThat(phone1.getBrand()).isEqualTo("Samsung");
+  }
+
+  @Test
+  public void testStartCall() {
+    phone1.powerOn();
+    phone1.startCall();
+
+    assertThat(phone1.isOn()).isTrue();
+    assertThat(phone1.getBatteryLevel()).isGreaterThan(5);
+    assertThat(phone1.isCallInProgress()).isTrue();
+  }
+
+  @Test
+  public void testStartCallCriticalBatteryThrowsException() {
+    assertThatThrownBy(() -> phone2.startCall())
+        .isInstanceOf(CriticalBatteryException.class)
+        .hasMessageContaining("Battery too low to start a call");
+  }
+
+  @Test
+  public void testGetCurrentVolume() {
+    assertThat(phone1.getCurrentVolume()).isEqualTo(Volume.LOW);
+  }
+
+  @Test
+  public void testSetCurrentVolume() {
+    phone1.setCurrentVolume(Volume.HIGH);
+    assertThat(phone1.getCurrentVolume()).isEqualTo(Volume.HIGH);
+  }
+
+  @Test
+  public void testPrintAllVolumeSettings() {
+    String allVolumes = phone1.printAllVolumeSettings();
+    assertThat(allVolumes).isEqualTo("MUTE, LOW, MEDIUM, HIGH");
+  }
+
+  @Test
+  public void testGetTextReady() {
+    List<String> texts = phone1.getTextReady();
+    assertThat(texts.size()).isEqualTo(2);
+    assertThat(texts).contains("Hello", "How are you?");
+  }
+
+  @Test
+  public void testAddTextReady() {
+    phone1.addTextReady("Ok");
+
+    List<String> texts = phone1.getTextReady();
+    assertThat(texts.size()).isEqualTo(3);
+    assertThat(texts).contains("Ok");
+  }
+}