Merge pull request #432 from PriyaKrishna/master

Core java enum examples

core-java-8/src/main/java/com/baeldung/enums/Pizza.java

@@ -0,0 +1,84 @@
+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;
+        }
+
+        private 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) {
+        EnumMap<PizzaStatusEnum, List<Pizza>> map = pzList.stream().collect(
+          Collectors.groupingBy(Pizza::getStatus,
+          () -> new EnumMap<PizzaStatusEnum, List<Pizza>>(PizzaStatusEnum.class), Collectors.toList()));
+        return map;
+    }
+
+    public void deliver() {
+        if (isDeliverable()) {
+            PizzaDeliverySystemConfiguration.getInstance().getDeliveryStrategy().deliver(this);
+            this.setStatus(PizzaStatusEnum.DELIVERED);
+        }
+    }
+}

core-java-8/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);
+}

core-java-8/src/main/java/com/baeldung/enums/PizzaDeliverySystemConfiguration.java

@@ -0,0 +1,21 @@
+package com.baeldung.enums;
+
+
+public enum PizzaDeliverySystemConfiguration {
+    INSTANCE ;
+    private 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;
+    }
+
+}

core-java-8/src/test/java/com/baeldung/enums/PizzaTest.java

@@ -0,0 +1,78 @@
+package com.baeldung.enums;
+
+
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.EnumMap;
+import java.util.List;
+
+import static junit.framework.TestCase.assertTrue;
+
+public class PizzaTest {
+    @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>();
+        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>();
+        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);
+    }
+}

core-java/pom.xml

@@ -9,7 +9,11 @@
     <dependencies>
 
         <!-- utils -->
-
+        <dependency>
+            <groupId>net.sourceforge.collections</groupId>
+            <artifactId>collections-generic</artifactId>
+            <version>4.01</version>
+        </dependency>
         <dependency>
             <groupId>com.google.guava</groupId>
             <artifactId>guava</artifactId>

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

@@ -0,0 +1,117 @@
+package com.baeldung.enums;
+
+import com.fasterxml.jackson.annotation.JsonFormat;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.apache.commons.collections15.CollectionUtils;
+import org.apache.commons.collections15.Predicate;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.EnumMap;
+import java.util.EnumSet;
+import java.util.List;
+
+public class Pizza {
+
+    private static EnumSet<PizzaStatusEnum> undeliveredPizzaStatuses =
+      EnumSet.of(PizzaStatusEnum.ORDERED, PizzaStatusEnum.READY);
+
+    private PizzaStatusEnum status;
+
+    @JsonFormat(shape = JsonFormat.Shape.OBJECT)
+    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;}
+        @JsonProperty("timeToDelivery")
+        public int getTimeToDelivery() {
+            return timeToDelivery;
+        }
+
+        private 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> getAllUndeliveredPizza(List<Pizza> input) {
+        List<Pizza> undelivered = input;
+        CollectionUtils.filter(undelivered, thatAreNotDelivered());
+        return undelivered;
+    }
+
+    public static EnumMap<PizzaStatusEnum, List<Pizza>> groupPizzaByStatus(List<Pizza> pizzaList) {
+        EnumMap<PizzaStatusEnum, List<Pizza>> pzByStatus = new EnumMap<PizzaStatusEnum, List<Pizza>>(PizzaStatusEnum.class);
+        for (Pizza pz : pizzaList) {
+            PizzaStatusEnum status = pz.getStatus();
+
+            if (pzByStatus.containsKey(status)) {
+                pzByStatus.get(status).add(pz);
+            } else {
+                List<Pizza> newPzList = new ArrayList<Pizza>();
+                newPzList.add(pz);
+                pzByStatus.put(status, newPzList);
+            }
+        }
+        return pzByStatus;
+    }
+
+    public void deliver() {
+        if (isDeliverable()) {
+            PizzaDeliverySystemConfiguration.getInstance().getDeliveryStrategy().deliver(this);
+            this.setStatus(PizzaStatusEnum.DELIVERED);
+        }
+    }
+
+    public static String getJsonString(Pizza pz) throws IOException {
+        ObjectMapper mapper = new ObjectMapper();
+        return mapper.writerWithDefaultPrettyPrinter().writeValueAsString(pz);
+    }
+
+    private static Predicate<Pizza> thatAreNotDelivered() {
+        return new Predicate<Pizza>() {
+            public boolean evaluate(Pizza entry) {
+                return undeliveredPizzaStatuses.contains(entry.getStatus());
+            }
+        };
+    }
+}

core-java/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);
+}

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

@@ -0,0 +1,20 @@
+package com.baeldung.enums;
+
+public enum PizzaDeliverySystemConfiguration {
+    INSTANCE ;
+    private 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;
+    }
+
+}

core-java/src/test/java/org/baeldung/java/enums/PizzaTest.java

@@ -0,0 +1,80 @@
+package org.baeldung.java.enums;
+
+
+import com.baeldung.enums.Pizza;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.EnumMap;
+import java.util.List;
+
+import static junit.framework.TestCase.assertTrue;
+
+
+public class PizzaTest {
+    @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>();
+        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.getAllUndeliveredPizza(pzList);
+        assertTrue(undeliveredPzs.size() == 3);
+    }
+
+    @Test
+    public void givenPizaOrders_whenGroupByStatusCalled_thenCorrectlyGrouped() {
+
+        List<Pizza> pzList = new ArrayList<Pizza>();
+        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);
+    }
+}