diff --git a/core-java-8/src/main/java/com/baeldung/enums/values/Element1.java b/core-java-8/src/main/java/com/baeldung/enums/values/Element1.java new file mode 100644 index 0000000000..6c80adacb1 --- /dev/null +++ b/core-java-8/src/main/java/com/baeldung/enums/values/Element1.java @@ -0,0 +1,17 @@ +package com.baeldung.enums.values; + +/** + * This is a simple enum of periodic table elements + */ +public enum Element1 { + H, + HE, + LI, + BE, + B, + C, + N, + O, + F, + NE +} diff --git a/core-java-8/src/main/java/com/baeldung/enums/values/Element2.java b/core-java-8/src/main/java/com/baeldung/enums/values/Element2.java new file mode 100644 index 0000000000..28bf3a475a --- /dev/null +++ b/core-java-8/src/main/java/com/baeldung/enums/values/Element2.java @@ -0,0 +1,52 @@ +package com.baeldung.enums.values; + +/** + * The simple enum has been enhanced to add the name of the element. + */ +public enum Element2 { + H("Hydrogen"), + HE("Helium"), + LI("Lithium"), + BE("Beryllium"), + B("Boron"), + C("Carbon"), + N("Nitrogen"), + O("Oxygen"), + F("Flourine"), + NE("Neon"); + + /** a final variable to store the label, which can't be changed */ + public final String label; + + /** + * A private constructor that sets the label. + * @param label + */ + private Element2(String label) { + this.label = label; + } + + /** + * Look up Element2 instances by the label field. This implementation iterates through + * the values() list to find the label. + * @param label The label to look up + * @return The Element2 instance with the label, or null if not found. + */ + public static Element2 valueOfLabel(String label) { + for (Element2 e2 : values()) { + if (e2.label.equals(label)) { + return e2; + } + } + return null; + } + + /** + * Override the toString() method to return the label instead of the declared name. + * @return + */ + @Override + public String toString() { + return this.label; + } +} diff --git a/core-java-8/src/main/java/com/baeldung/enums/values/Element3.java b/core-java-8/src/main/java/com/baeldung/enums/values/Element3.java new file mode 100644 index 0000000000..cb98695de8 --- /dev/null +++ b/core-java-8/src/main/java/com/baeldung/enums/values/Element3.java @@ -0,0 +1,63 @@ +package com.baeldung.enums.values; + +import java.util.HashMap; +import java.util.Map; + +/** + * A Map has been added to cache labels for faster lookup. + */ +public enum Element3 { + H("Hydrogen"), + HE("Helium"), + LI("Lithium"), + BE("Beryllium"), + B("Boron"), + C("Carbon"), + N("Nitrogen"), + O("Oxygen"), + F("Flourine"), + NE("Neon"); + + /** + * A map to cache labels and their associated Element3 instances. + * Note that this only works if the labels are all unique! + */ + private static final Map BY_LABEL = new HashMap<>(); + + /** populate the BY_LABEL cache */ + static { + for (Element3 e3 : values()) { + BY_LABEL.put(e3.label, e3); + } + } + + /** a final variable to store the label, which can't be changed */ + public final String label; + + /** + * A private constructor that sets the label. + * @param label + */ + private Element3(String label) { + this.label = label; + } + + /** + * Look up Element2 instances by the label field. This implementation finds the + * label in the BY_LABEL cache. + * @param label The label to look up + * @return The Element3 instance with the label, or null if not found. + */ + public static Element3 valueOfLabel(String label) { + return BY_LABEL.get(label); + } + + /** + * Override the toString() method to return the label instead of the declared name. + * @return + */ + @Override + public String toString() { + return this.label; + } +} diff --git a/core-java-8/src/main/java/com/baeldung/enums/values/Element4.java b/core-java-8/src/main/java/com/baeldung/enums/values/Element4.java new file mode 100644 index 0000000000..89c45f9d1b --- /dev/null +++ b/core-java-8/src/main/java/com/baeldung/enums/values/Element4.java @@ -0,0 +1,95 @@ +package com.baeldung.enums.values; + +import java.util.HashMap; +import java.util.Map; + +/** + * Multiple fields have been added and the Labeled interface is implemented. + */ +public enum Element4 implements Labeled { + H("Hydrogen", 1, 1.008f), + HE("Helium", 2, 4.0026f), + LI("Lithium", 3, 6.94f), + BE("Beryllium", 4, 9.01722f), + B("Boron", 5, 10.81f), + C("Carbon", 6, 12.011f), + N("Nitrogen", 7, 14.007f), + O("Oxygen", 8, 15.999f), + F("Flourine", 9, 18.998f), + NE("Neon", 10, 20.180f); + /** + * Maps cache labels and their associated Element3 instances. + * Note that this only works if the values are all unique! + */ + private static final Map BY_LABEL = new HashMap<>(); + private static final Map BY_ATOMIC_NUMBER = new HashMap<>(); + private static final Map BY_ATOMIC_WEIGHT = new HashMap<>(); + + /** populate the caches */ + static { + for (Element4 e4 : values()) { + BY_LABEL.put(e4.label, e4); + BY_ATOMIC_NUMBER.put(e4.atomicNumber, e4); + BY_ATOMIC_WEIGHT.put(e4.atomicWeight, e4); + } + } + + /** final variables to store the values, which can't be changed */ + public final String label; + public final int atomicNumber; + public final float atomicWeight; + + private Element4(String label, int atomicNumber, float atomicWeight) { + this.label = label; + this.atomicNumber = atomicNumber; + this.atomicWeight = atomicWeight; + } + + /** + * Implement the Labeled interface. + * @return the label value + */ + @Override + public String label() { + return label; + } + + /** + * Look up Element2 instances by the label field. This implementation finds the + * label in the BY_LABEL cache. + * @param label The label to look up + * @return The Element4 instance with the label, or null if not found. + */ + public static Element4 valueOfLabel(String label) { + return BY_LABEL.get(label); + } + + /** + * Look up Element2 instances by the atomicNumber field. This implementation finds the + * atomicNUmber in the cache. + * @param number The atomicNumber to look up + * @return The Element4 instance with the label, or null if not found. + */ + public static Element4 valueOfAtomicNumber(int number) { + return BY_ATOMIC_NUMBER.get(number); + } + + /** + * Look up Element2 instances by the atomicWeight field. This implementation finds the + * atomic weight in the cache. + * @param weight the atomic weight to look up + * @return The Element4 instance with the label, or null if not found. + */ + public static Element4 valueOfAtomicWeight(float weight) { + return BY_ATOMIC_WEIGHT.get(weight); + } + + /** + * Override the toString() method to return the label instead of the declared name. + * @return + */ + @Override + public String toString() { + return this.label; + } +} diff --git a/core-java-8/src/main/java/com/baeldung/enums/values/Labeled.java b/core-java-8/src/main/java/com/baeldung/enums/values/Labeled.java new file mode 100644 index 0000000000..e41d6525f1 --- /dev/null +++ b/core-java-8/src/main/java/com/baeldung/enums/values/Labeled.java @@ -0,0 +1,5 @@ +package com.baeldung.enums.values; + +public interface Labeled { + String label(); +} diff --git a/core-java-8/src/test/java/com/baeldung/enums/values/Element1UnitTest.java b/core-java-8/src/test/java/com/baeldung/enums/values/Element1UnitTest.java new file mode 100644 index 0000000000..ab3e684230 --- /dev/null +++ b/core-java-8/src/test/java/com/baeldung/enums/values/Element1UnitTest.java @@ -0,0 +1,48 @@ +package com.baeldung.enums.values; + +import org.junit.After; +import org.junit.AfterClass; +import org.junit.Before; +import org.junit.BeforeClass; +import org.junit.Test; +import static org.junit.Assert.*; + +/** + * + * @author chris + */ +public class Element1UnitTest { + + public Element1UnitTest() { + } + + @BeforeClass + public static void setUpClass() { + } + + @AfterClass + public static void tearDownClass() { + } + + @Before + public void setUp() { + } + + @After + public void tearDown() { + } + + @Test + public void whenAccessingToString_thenItShouldEqualName() { + for (Element1 e1 : Element1.values()) { + assertEquals(e1.name(), e1.toString()); + } + } + + @Test + public void whenCallingValueOf_thenReturnTheCorrectEnum() { + for (Element1 e1 : Element1.values()) { + assertSame(e1, Element1.valueOf(e1.name())); + } + } +} diff --git a/core-java-8/src/test/java/com/baeldung/enums/values/Element2UnitTest.java b/core-java-8/src/test/java/com/baeldung/enums/values/Element2UnitTest.java new file mode 100644 index 0000000000..02995a2f41 --- /dev/null +++ b/core-java-8/src/test/java/com/baeldung/enums/values/Element2UnitTest.java @@ -0,0 +1,59 @@ +/* + * To change this license header, choose License Headers in Project Properties. + * To change this template file, choose Tools | Templates + * and open the template in the editor. + */ +package com.baeldung.enums.values; + +import org.junit.After; +import org.junit.AfterClass; +import org.junit.Before; +import org.junit.BeforeClass; +import org.junit.Test; +import static org.junit.Assert.*; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * + * @author chris + */ +public class Element2UnitTest { + private static final Logger LOGGER = LoggerFactory.getLogger(Element2UnitTest.class); + + public Element2UnitTest() { + } + + @BeforeClass + public static void setUpClass() { + } + + @AfterClass + public static void tearDownClass() { + } + + @Before + public void setUp() { + } + + @After + public void tearDown() { + } + + @Test + public void whenLocatebyLabel_thenReturnCorrectValue() { + for (Element2 e2 : Element2.values()) { + assertSame(e2, Element2.valueOfLabel(e2.label)); + } + } + + /** + * Test of toString method, of class Element2. + */ + @Test + public void whenCallingToString_thenReturnLabel() { + for (Element2 e2 : Element2.values()) { + assertEquals(e2.label, e2.toString()); + } + } +} diff --git a/core-java-8/src/test/java/com/baeldung/enums/values/Element3UnitTest.java b/core-java-8/src/test/java/com/baeldung/enums/values/Element3UnitTest.java new file mode 100644 index 0000000000..40c76a97b1 --- /dev/null +++ b/core-java-8/src/test/java/com/baeldung/enums/values/Element3UnitTest.java @@ -0,0 +1,57 @@ +/* + * To change this license header, choose License Headers in Project Properties. + * To change this template file, choose Tools | Templates + * and open the template in the editor. + */ +package com.baeldung.enums.values; + +import org.junit.After; +import org.junit.AfterClass; +import org.junit.Before; +import org.junit.BeforeClass; +import org.junit.Test; +import static org.junit.Assert.*; + +/** + * + * @author chris + */ +public class Element3UnitTest { + + public Element3UnitTest() { + } + + @BeforeClass + public static void setUpClass() { + } + + @AfterClass + public static void tearDownClass() { + } + + @Before + public void setUp() { + } + + @After + public void tearDown() { + } + + @Test + public void whenLocatebyLabel_thenReturnCorrectValue() { + for (Element3 e3 : Element3.values()) { + assertSame(e3, Element3.valueOfLabel(e3.label)); + } + } + + /** + * Test of toString method, of class Element3. + */ + @Test + public void whenCallingToString_thenReturnLabel() { + for (Element3 e3 : Element3.values()) { + assertEquals(e3.label, e3.toString()); + } + } + +} diff --git a/core-java-8/src/test/java/com/baeldung/enums/values/Element4UnitTest.java b/core-java-8/src/test/java/com/baeldung/enums/values/Element4UnitTest.java new file mode 100644 index 0000000000..d349dcef72 --- /dev/null +++ b/core-java-8/src/test/java/com/baeldung/enums/values/Element4UnitTest.java @@ -0,0 +1,71 @@ +/* + * To change this license header, choose License Headers in Project Properties. + * To change this template file, choose Tools | Templates + * and open the template in the editor. + */ +package com.baeldung.enums.values; + +import org.junit.After; +import org.junit.AfterClass; +import org.junit.Before; +import org.junit.BeforeClass; +import org.junit.Test; +import static org.junit.Assert.*; + +/** + * + * @author chris + */ +public class Element4UnitTest { + + public Element4UnitTest() { + } + + @BeforeClass + public static void setUpClass() { + } + + @AfterClass + public static void tearDownClass() { + } + + @Before + public void setUp() { + } + + @After + public void tearDown() { + } + + @Test + public void whenLocatebyLabel_thenReturnCorrectValue() { + for (Element4 e4 : Element4.values()) { + assertSame(e4, Element4.valueOfLabel(e4.label)); + } + } + + @Test + public void whenLocatebyAtmNum_thenReturnCorrectValue() { + for (Element4 e4 : Element4.values()) { + assertSame(e4, Element4.valueOfAtomicNumber(e4.atomicNumber)); + } + } + + @Test + public void whenLocatebyAtmWt_thenReturnCorrectValue() { + for (Element4 e4 : Element4.values()) { + assertSame(e4, Element4.valueOfAtomicWeight(e4.atomicWeight)); + } + } + + /** + * Test of toString method, of class Element4. + */ + @Test + public void whenCallingToString_thenReturnLabel() { + for (Element4 e4 : Element4.values()) { + assertEquals(e4.label, e4.toString()); + } + } + +}