[BAEL-8232] - Moved code from core-java to java-strings module for 'Converting Strings to Enums in Java' article

java-strings/src/main/java/com/baeldung/enums/Pizza.java

@@ -0,0 +1,88 @@
+package com.baeldung.enums;
+
+import java.util.EnumMap;
+import java.util.EnumSet;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class Pizza {
+
+    private static EnumSet<PizzaStatusEnum> deliveredPizzaStatuses = EnumSet.of(PizzaStatusEnum.DELIVERED);
+
+    private PizzaStatusEnum status;
+
+    public enum PizzaStatusEnum {
+        ORDERED(5) {
+            @Override
+            public boolean isOrdered() {
+                return true;
+            }
+        },
+        READY(2) {
+            @Override
+            public boolean isReady() {
+                return true;
+            }
+        },
+        DELIVERED(0) {
+            @Override
+            public boolean isDelivered() {
+                return true;
+            }
+        };
+
+        private int timeToDelivery;
+
+        public boolean isOrdered() {
+            return false;
+        }
+
+        public boolean isReady() {
+            return false;
+        }
+
+        public boolean isDelivered() {
+            return false;
+        }
+
+        public int getTimeToDelivery() {
+            return timeToDelivery;
+        }
+
+        PizzaStatusEnum(int timeToDelivery) {
+            this.timeToDelivery = timeToDelivery;
+        }
+    }
+
+    public PizzaStatusEnum getStatus() {
+        return status;
+    }
+
+    public void setStatus(PizzaStatusEnum status) {
+        this.status = status;
+    }
+
+    public boolean isDeliverable() {
+        return this.status.isReady();
+    }
+
+    public void printTimeToDeliver() {
+        System.out.println("Time to delivery is " + this.getStatus().getTimeToDelivery() + " days");
+    }
+
+    public static List<Pizza> getAllUndeliveredPizzas(List<Pizza> input) {
+        return input.stream().filter((s) -> !deliveredPizzaStatuses.contains(s.getStatus())).collect(Collectors.toList());
+    }
+
+    public static EnumMap<PizzaStatusEnum, List<Pizza>> groupPizzaByStatus(List<Pizza> pzList) {
+        return pzList.stream().collect(Collectors.groupingBy(Pizza::getStatus, () -> new EnumMap<>(PizzaStatusEnum.class), Collectors.toList()));
+    }
+
+    public void deliver() {
+        if (isDeliverable()) {
+            PizzaDeliverySystemConfiguration.getInstance().getDeliveryStrategy().deliver(this);
+            this.setStatus(PizzaStatusEnum.DELIVERED);
+        }
+    }
+
+}

java-strings/src/main/java/com/baeldung/enums/PizzaDeliveryStrategy.java

@@ -0,0 +1,18 @@
+package com.baeldung.enums;
+
+public enum PizzaDeliveryStrategy {
+    EXPRESS {
+        @Override
+        public void deliver(Pizza pz) {
+            System.out.println("Pizza will be delivered in express mode");
+        }
+    },
+    NORMAL {
+        @Override
+        public void deliver(Pizza pz) {
+            System.out.println("Pizza will be delivered in normal mode");
+        }
+    };
+
+    public abstract void deliver(Pizza pz);
+}

java-strings/src/main/java/com/baeldung/enums/PizzaDeliverySystemConfiguration.java

@@ -0,0 +1,21 @@
+package com.baeldung.enums;
+
+public enum PizzaDeliverySystemConfiguration {
+    INSTANCE;
+
+    PizzaDeliverySystemConfiguration() {
+        // Do the configuration initialization which
+        // involves overriding defaults like delivery strategy
+    }
+
+    private PizzaDeliveryStrategy deliveryStrategy = PizzaDeliveryStrategy.NORMAL;
+
+    public static PizzaDeliverySystemConfiguration getInstance() {
+        return INSTANCE;
+    }
+
+    public PizzaDeliveryStrategy getDeliveryStrategy() {
+        return deliveryStrategy;
+    }
+
+}

java-strings/src/main/java/com/baeldung/enums/README.md

@@ -0,0 +1,2 @@
+### Relevant Articles:
+- [A Guide to Java Enums](http://www.baeldung.com/a-guide-to-java-enums)

java-strings/src/test/java/com/baeldung/enums/PizzaUnitTest.java

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+package com.baeldung.enums;
+
+import com.baeldung.enums.Pizza.PizzaStatusEnum;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.EnumMap;
+import java.util.List;
+
+import static junit.framework.TestCase.assertTrue;
+
+public class PizzaUnitTest {
+
+    @Test
+    public void givenPizaOrder_whenReady_thenDeliverable() {
+        Pizza testPz = new Pizza();
+        testPz.setStatus(Pizza.PizzaStatusEnum.READY);
+        assertTrue(testPz.isDeliverable());
+    }
+
+    @Test
+    public void givenPizaOrders_whenRetrievingUnDeliveredPzs_thenCorrectlyRetrieved() {
+        List<Pizza> pzList = new ArrayList<>();
+        Pizza pz1 = new Pizza();
+        pz1.setStatus(Pizza.PizzaStatusEnum.DELIVERED);
+
+        Pizza pz2 = new Pizza();
+        pz2.setStatus(Pizza.PizzaStatusEnum.ORDERED);
+
+        Pizza pz3 = new Pizza();
+        pz3.setStatus(Pizza.PizzaStatusEnum.ORDERED);
+
+        Pizza pz4 = new Pizza();
+        pz4.setStatus(Pizza.PizzaStatusEnum.READY);
+
+        pzList.add(pz1);
+        pzList.add(pz2);
+        pzList.add(pz3);
+        pzList.add(pz4);
+
+        List<Pizza> undeliveredPzs = Pizza.getAllUndeliveredPizzas(pzList);
+        assertTrue(undeliveredPzs.size() == 3);
+    }
+
+    @Test
+    public void givenPizaOrders_whenGroupByStatusCalled_thenCorrectlyGrouped() {
+
+        List<Pizza> pzList = new ArrayList<>();
+        Pizza pz1 = new Pizza();
+        pz1.setStatus(Pizza.PizzaStatusEnum.DELIVERED);
+
+        Pizza pz2 = new Pizza();
+        pz2.setStatus(Pizza.PizzaStatusEnum.ORDERED);
+
+        Pizza pz3 = new Pizza();
+        pz3.setStatus(Pizza.PizzaStatusEnum.ORDERED);
+
+        Pizza pz4 = new Pizza();
+        pz4.setStatus(Pizza.PizzaStatusEnum.READY);
+
+        pzList.add(pz1);
+        pzList.add(pz2);
+        pzList.add(pz3);
+        pzList.add(pz4);
+
+        EnumMap<Pizza.PizzaStatusEnum, List<Pizza>> map = Pizza.groupPizzaByStatus(pzList);
+        assertTrue(map.get(Pizza.PizzaStatusEnum.DELIVERED).size() == 1);
+        assertTrue(map.get(Pizza.PizzaStatusEnum.ORDERED).size() == 2);
+        assertTrue(map.get(Pizza.PizzaStatusEnum.READY).size() == 1);
+    }
+
+    @Test
+    public void whenDelivered_thenPizzaGetsDeliveredAndStatusChanges() {
+        Pizza pz = new Pizza();
+        pz.setStatus(Pizza.PizzaStatusEnum.READY);
+        pz.deliver();
+        assertTrue(pz.getStatus() == Pizza.PizzaStatusEnum.DELIVERED);
+    }
+    
+    @Test
+    public void whenConvertedIntoEnum_thenGetsConvertedCorrectly() {
+        String pizzaEnumValue = "READY";
+        PizzaStatusEnum pizzaStatusEnum = PizzaStatusEnum.valueOf(pizzaEnumValue);
+        assertTrue(pizzaStatusEnum == PizzaStatusEnum.READY);
+    }
+    
+    @Test(expected = IllegalArgumentException.class)
+    public void whenConvertedIntoEnum_thenThrowsException() {
+        String pizzaEnumValue = "rEAdY";
+        PizzaStatusEnum pizzaStatusEnum = PizzaStatusEnum.valueOf(pizzaEnumValue);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void givenInvalidEnumValueContentWiseAsString_whenConvertedIntoEnum_thenThrowsException() {
+        String pizzaEnumValue = "invalid";
+        PizzaStatusEnum pizzaStatusEnum = PizzaStatusEnum.valueOf(pizzaEnumValue);
+    }
+    
+
+}

java-strings/src/test/java/org/baeldung/java/enums/PizzaUnitTest.java

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+package org.baeldung.java.enums;
+
+import static junit.framework.TestCase.assertTrue;
+
+import java.util.ArrayList;
+import java.util.EnumMap;
+import java.util.List;
+
+import org.junit.Test;
+
+import com.baeldung.enums.Pizza;
+
+public class PizzaUnitTest {
+
+    @Test
+    public void givenPizaOrder_whenReady_thenDeliverable() {
+        Pizza testPz = new Pizza();
+        testPz.setStatus(Pizza.PizzaStatusEnum.READY);
+        assertTrue(testPz.isDeliverable());
+    }
+
+    @Test
+    public void givenPizaOrders_whenRetrievingUnDeliveredPzs_thenCorrectlyRetrieved() {
+        List<Pizza> pzList = new ArrayList<>();
+        Pizza pz1 = new Pizza();
+        pz1.setStatus(Pizza.PizzaStatusEnum.DELIVERED);
+
+        Pizza pz2 = new Pizza();
+        pz2.setStatus(Pizza.PizzaStatusEnum.ORDERED);
+
+        Pizza pz3 = new Pizza();
+        pz3.setStatus(Pizza.PizzaStatusEnum.ORDERED);
+
+        Pizza pz4 = new Pizza();
+        pz4.setStatus(Pizza.PizzaStatusEnum.READY);
+
+        pzList.add(pz1);
+        pzList.add(pz2);
+        pzList.add(pz3);
+        pzList.add(pz4);
+
+        List<Pizza> undeliveredPzs = Pizza.getAllUndeliveredPizzas(pzList);
+        assertTrue(undeliveredPzs.size() == 3);
+    }
+
+    @Test
+    public void givenPizaOrders_whenGroupByStatusCalled_thenCorrectlyGrouped() {
+
+        List<Pizza> pzList = new ArrayList<>();
+        Pizza pz1 = new Pizza();
+        pz1.setStatus(Pizza.PizzaStatusEnum.DELIVERED);
+
+        Pizza pz2 = new Pizza();
+        pz2.setStatus(Pizza.PizzaStatusEnum.ORDERED);
+
+        Pizza pz3 = new Pizza();
+        pz3.setStatus(Pizza.PizzaStatusEnum.ORDERED);
+
+        Pizza pz4 = new Pizza();
+        pz4.setStatus(Pizza.PizzaStatusEnum.READY);
+
+        pzList.add(pz1);
+        pzList.add(pz2);
+        pzList.add(pz3);
+        pzList.add(pz4);
+
+        EnumMap<Pizza.PizzaStatusEnum, List<Pizza>> map = Pizza.groupPizzaByStatus(pzList);
+        assertTrue(map.get(Pizza.PizzaStatusEnum.DELIVERED).size() == 1);
+        assertTrue(map.get(Pizza.PizzaStatusEnum.ORDERED).size() == 2);
+        assertTrue(map.get(Pizza.PizzaStatusEnum.READY).size() == 1);
+    }
+
+    @Test
+    public void givenPizaOrder_whenDelivered_thenPizzaGetsDeliveredAndStatusChanges() {
+        Pizza pz = new Pizza();
+        pz.setStatus(Pizza.PizzaStatusEnum.READY);
+        pz.deliver();
+        assertTrue(pz.getStatus() == Pizza.PizzaStatusEnum.DELIVERED);
+    }
+
+}