Andrey Filyanin / filyaniny@gmail.com

core-scala/src/main/scala/com/baeldung/scala/Events.scala

@@ -0,0 +1,41 @@
+package com.baeldung.scala
+
+abstract class EventAbstract {
+ val eventType: String
+ var applicationId: Int = 99
+ def debug = { println(toJson) }
+ def toJson: String
+}
+
+trait EventTrait {
+ val eventType: String
+ var applicationId: Int = 99
+ def debug = { println(toJson) }
+ def toJson: String
+}
+
+class NewPostArrivedEventA extends EventAbstract {
+ val eventType: String = "NewPost"
+ def toJson: String = s"""{"type": "$eventType", "appId": $applicationId}"""
+}
+
+class NewPostArrivedEventT extends EventTrait {
+ val eventType: String = "NewPost"
+ def toJson: String = s"""{"type": "$eventType", "appId": $applicationId}"""
+}
+
+
+trait Event2 {
+ val eventType: String
+ var applicationId: Int = 99
+}
+
+trait Debug {
+ def debug = { println(toJson) }
+ def toJson: String
+}
+
+class SimpleEvent extends Event2 with Debug {
+ val eventType: String = "simpleType"
+ def toJson: String = s"""{"type": "$eventType", "appId": $applicationId}"""
+}

core-scala/src/main/scala/com/baeldung/scala/StackableChange.scala

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+package com.baeldung.scala
+
+abstract class EventSender {
+ def envelope(payload: String): String
+}
+
+class SimpleEventSender extends EventSender {
+ def envelope(payload: String): String = {
+ s"""{ payload: $payload }"""
+ }
+}
+
+trait EventFirstSender extends EventSender {
+ abstract override def envelope(payload: String): String = {
+ s"""{ firstSender: ${super.envelope(payload)} }"""
+ }
+}
+
+trait EventSecondSender extends EventSender {
+ abstract override def envelope(payload: String): String = {
+ s"""{ secondSender: ${super.envelope(payload)} }"""
+ }
+}
+
+trait EventThirdSender extends EventSender {
+ abstract override def envelope(payload: String): String = {
+ s"""{ thirdSender: ${super.envelope(payload)} }"""
+ }
+}
+
+
+
+
+

core-scala/src/test/scala/com/baeldung/scala/MultipleInheritanceTest.scala

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+package com.baeldung.scala
+
+import org.junit.Test
+
+class MultipleInheritanceTest {
+
+ val expected: String = """{"type": "SimpleType"}"""
+
+ @Test
+ def whenMultipleTraitsInherited_thenFunctionalityExtended() = {
+
+ // Set up a an objects with abstract parent and Trait
+ val ev = new SimpleEvent() with Debug
+
+ // We expected object have extended functionality
+ ev.debug
+ }
+}

core-scala/src/test/scala/com/baeldung/scala/StackableChangeTest.scala

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+package com.baeldung.scala
+
+import org.junit.Assert.assertFalse
+import org.junit.Test
+
+class StackableChangeTest {
+
+ @Test
+ def whenFirstTraitOrderDefined_thenOneResult() = {
+
+ // Set up a an object with stackable Traits
+ val sender = new SimpleEventSender with EventFirstSender with EventSecondSender with EventThirdSender
+
+ // Let's provide some payload to envelope
+
+ val enveloped = sender.envelope("data")
+
+ val expected = "{ thirdSender: { secondSender: { firstSender: { payload: data } } } }"
+ assert(enveloped == expected)
+ }
+
+ @Test
+ def whenSecondTraitOrderDefined_thenOtherResult() = {
+
+ // Set up a an object with stackable Traits with different order
+ val sender = new SimpleEventSender with EventThirdSender with EventSecondSender with EventFirstSender
+
+ // Let's provide some payload to envelope
+
+ val enveloped = sender.envelope("data")
+
+ assert(enveloped == "{ firstSender: { secondSender: { thirdSender: { payload: data } } } }")
+ }
+}

core-scala/src/test/scala/com/baeldung/scala/TraitVsAbstractClassTest.scala

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+package com.baeldung.scala
+
+import org.junit.Test
+
+class TraitVsAbstractClassTest {
+
+ @Test
+ def whenDifferentObjectsFromDifferentParents_thenBehaveTheSame() = {
+
+ // Set up a an objects with abstract parent and Trait
+ val eventFromAbstract = new NewPostArrivedEventA
+ val eventFromTrait = new NewPostArrivedEventT
+
+ // We expected the same behavior
+ assert(eventFromAbstract.toJson == eventFromTrait.toJson)
+ }
+}