Gemeinsames Lernen

src/org/eidecker/mapreduce/DistanceCounter.java

@@ -0,0 +1,57 @@
+package org.eidecker.mapreduce;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+import org.junit.jupiter.api.Test;
+
+/**
+ * @author seidecke.
+ */
+public class DistanceCounter {
+
+	private static Integer komplizierteBerechnungMitRestCall(Integer strecke, Integer strecke2) {
+		return strecke2 - strecke;
+	}
+
+	@Test
+	public void testDistanceSum() {
+		assertEquals(55, distanceSum(orte()));
+	}
+
+	private Integer distanceSum(List<Stopp> orte) {
+		Optional<Integer> distanceSum = orte.stream()
+				.map(Stopp::getWichtigeDingeZurBerechnung)
+				.reduce(DistanceCounter::komplizierteBerechnungMitRestCall);
+
+		return distanceSum.orElse(0);
+	}
+
+
+
+
+
+	private List<Stopp> orte() {
+		return IntStream.rangeClosed(1,10).boxed().map(Stopp::new).collect(Collectors.toList());
+	}
+
+//	private BinaryOperator<Ort> distanceAdder = (ort, ort2) -> ort2.getWert() - ort.getWert();
+//
+//	private BiFunction<Ort, Ort, Integer> distanceAdder = (ort, ort2) -> ort2.getWert() - ort.getWert();
+
+	class Stopp {
+		Integer wert;
+
+		public Stopp(Integer wert) {
+			this.wert = wert;
+		}
+
+		public Integer getWichtigeDingeZurBerechnung() {
+			return wert;
+		}
+	}
+
+}

src/org/eidecker/oca8lernen/general/CastExceptions.java

@@ -0,0 +1,46 @@
+package org.eidecker.oca8lernen.general;
+
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * @author seidecke.
+ */
+public class CastExceptions {
+
+	@Test
+	public void testCastExceptions() {
+
+		OberCast eigentlichUnter = new UnterCast();
+		OberCast wirklichOber = new OberCast();
+		UnterCast purUnter = new UnterCast();
+
+		Außerhalb außerhalb = new Außerhalb();
+
+		OberCast ober = purUnter;
+
+		UnterCast unter = (UnterCast) eigentlichUnter;
+
+		// Runtime-Exception, da innerhalb der Typenhierarchie
+		assertThrows(ClassCastException.class, () -> {
+			UnterCast unter3 = (UnterCast) wirklichOber;
+		});
+
+		// Compilefehler, da Versuch des Casts außerhalb der Typenhierarchie
+		// UnterCast unter2 = (UnterCast) außerhalb;
+
+	}
+}
+
+class OberCast {
+
+}
+
+class UnterCast extends OberCast {
+
+}
+
+class Außerhalb {
+
+}

src/org/eidecker/oca8lernen/general/Interfaces.java

@@ -1,8 +1,6 @@
 package org.eidecker.oca8lernen.general;
 
-import com.sun.xml.internal.ws.policy.privateutil.PolicyUtils;
 import java.io.IOException;
-import java.nio.file.AccessDeniedException;
 import org.junit.jupiter.api.Test;
 
 class TestInterfaces {

src/org/eidecker/oca8lernen/general/Overloading.java

@@ -1,14 +1,18 @@
 package org.eidecker.oca8lernen.general;
 
-import org.junit.jupiter.api.Test;
+import static org.eidecker.oca8lernen.general.PrimitiveOverloading.VARIANTE_BYTE;
+import static org.eidecker.oca8lernen.general.PrimitiveOverloading.VARIANTE_CHAR;
+import static org.eidecker.oca8lernen.general.PrimitiveOverloading.VARIANTE_CHARACTER;
+import static org.eidecker.oca8lernen.general.PrimitiveOverloading.VARIANTE_INT;
+import static org.eidecker.oca8lernen.general.PrimitiveOverloading.VARIANTE_INTEGER;
+import static org.eidecker.oca8lernen.general.PrimitiveOverloading.VARIANTE_LONG_PRIMITIVE;
+import static org.eidecker.oca8lernen.general.PrimitiveOverloading.VARIANTE_LONG_WRAPPER;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
 import java.util.LinkedList;
 import java.util.List;
-
-import static org.eidecker.oca8lernen.general.PrimitiveOverloading.*;
-import static org.eidecker.oca8lernen.general.Overloading.*;
-import static org.junit.jupiter.api.Assertions.assertEquals;
+import org.junit.jupiter.api.Test;
 
 class OverloadingTester {
 
@@ -21,6 +25,9 @@ class OverloadingTester {
 		SubOverloading subOverloading = new SubOverloading();
 		System.out.println(subOverloading.staticString);
 		System.out.println(subOverloading.overrideStatic());
+
+		List l = null;
+		subOverloading.overloadMe(l);
 	}
 }
 

src/org/eidecker/oca8lernen/general/StringIndex.java

@@ -0,0 +1,67 @@
+package org.eidecker.oca8lernen.general;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * @author seidecke.
+ */
+public class StringIndex {
+
+	private static String testString = "1234567890";
+
+	@Test
+	public void testSomeStrings() {
+		assertEquals('3', testString.charAt(2));
+		assertEquals("67890", testString.substring(5));
+		assertEquals("67", testString.substring(5,7));
+		assertEquals("", testString.substring(5,5));
+		assertEquals(10, testString.length());
+		assertThrows(IndexOutOfBoundsException.class, () -> testString.substring(-1));
+		assertThrows(IndexOutOfBoundsException.class, () -> testString.substring(5,4));
+		assertThrows(IndexOutOfBoundsException.class, () -> testString.substring(5,11));
+
+		String s = "123456";
+		assertEquals("1234567", s += "7");
+	}
+
+	@Test
+	public void testSomeStringBuilders() {
+		StringBuilder testStringBuilder = new StringBuilder("1234567890");
+
+		assertEquals('3', testStringBuilder.charAt(2));
+		testStringBuilder = new StringBuilder("1234567890");
+		assertEquals("67890", testStringBuilder.substring(5));
+		testStringBuilder = new StringBuilder("1234567890");
+		assertEquals("67", testStringBuilder.substring(5,7));
+		testStringBuilder = new StringBuilder("1234567890");
+		assertEquals("", testStringBuilder.substring(5,5));
+		testStringBuilder = new StringBuilder("1234567890");
+		assertEquals(10, testStringBuilder.length());
+		testStringBuilder = new StringBuilder("1234567890");
+		assertThrows(IndexOutOfBoundsException.class, () -> new StringBuilder("1234567890").substring(-1));
+		testStringBuilder = new StringBuilder("1234567890");
+		assertThrows(IndexOutOfBoundsException.class, () -> new StringBuilder("1234567890").substring(5,4));
+		testStringBuilder = new StringBuilder("1234567890");
+		assertThrows(IndexOutOfBoundsException.class, () -> new StringBuilder("1234567890").substring(5,11));
+
+		testStringBuilder = new StringBuilder("1234567890");
+		assertThrows(IndexOutOfBoundsException.class, () -> new StringBuilder("1234567890").delete(13,1));
+		testStringBuilder = new StringBuilder("1234567890");
+		assertThrows(IndexOutOfBoundsException.class, () -> new StringBuilder("1234567890").insert(11,"Hallo"));
+
+		// null direkt nicht moeglich, da ueberladene Methode nicht bestimmt werden kann
+		// testStringBuilder.insert(1, null);
+
+		testStringBuilder = new StringBuilder("1234567890");
+		assertEquals("12345890", testStringBuilder.delete(5,7).toString());
+		testStringBuilder = new StringBuilder("1234567890");
+		assertEquals("71234567890", testStringBuilder.insert(0,7).toString());
+		testStringBuilder = new StringBuilder("1234567890");
+		assertEquals("1true234567890", testStringBuilder.insert(1,true).toString());
+	}
+
+
+}

src/org/eidecker/test/OptionalAPI.java

@@ -0,0 +1,30 @@
+package org.eidecker.test;
+
+import java.util.Optional;
+import org.junit.jupiter.api.Test;
+
+/**
+ * @author seidecke.
+ */
+public class OptionalAPI {
+
+	@Test
+	public void testOptionalMapping() {
+
+
+
+
+	}
+
+}
+
+
+class DataHolder {
+	public Optional<String> value;
+
+	public DataHolder() {
+		value = Optional.empty();
+	}
+
+
+}