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Java Hashmap with different value types (eugenp#11495)
* Java Hashmap with different value types * some fixes according to review comments * convert liveTest -> unitTest * convert liveTest -> unitTest
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‎core-java-modules/core-java-collections-4/src/main/java/com/baeldung/collections/mulipletypesinmap/DynamicTypeValue.java‎

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package com.baeldung.collections.mulipletypesinmap;
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public interface DynamicTypeValue {
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String valueDescription();
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}

‎core-java-modules/core-java-collections-4/src/main/java/com/baeldung/collections/mulipletypesinmap/InstantTypeValue.java‎

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package com.baeldung.collections.mulipletypesinmap;
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import java.time.Instant;
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import java.time.ZoneId;
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import java.time.format.DateTimeFormatter;
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public class InstantTypeValue implements DynamicTypeValue {
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private static DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")
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.withZone(ZoneId.systemDefault());
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private Instant value;
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public InstantTypeValue(Instant value) {
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this.value = value;
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}
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@Override
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public String valueDescription() {
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if (value == null) {
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return "The value is null.";
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}
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return String.format("The value is an instant: %s", FORMATTER.format(value));
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}
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}

‎core-java-modules/core-java-collections-4/src/main/java/com/baeldung/collections/mulipletypesinmap/IntArrayTypeValue.java‎

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package com.baeldung.collections.mulipletypesinmap;
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import java.util.Arrays;
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public class IntArrayTypeValue implements DynamicTypeValue {
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private int[] value;
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public IntArrayTypeValue(int[] value) {
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this.value = value;
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}
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@Override
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public String valueDescription() {
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if (value == null) {
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return "The value is null.";
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}
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return String.format("The value is an array of %d integers: %s", value.length, Arrays.toString(value));
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}
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}

‎core-java-modules/core-java-collections-4/src/main/java/com/baeldung/collections/mulipletypesinmap/IntegerTypeValue.java‎

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package com.baeldung.collections.mulipletypesinmap;
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public class IntegerTypeValue implements DynamicTypeValue {
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private Integer value;
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public IntegerTypeValue(Integer value) {
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this.value = value;
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}
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@Override
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public String valueDescription() {
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if(value == null){
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return "The value is null.";
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}
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return String.format("The value is a %s integer: %d", value > 0 ? "positive" : "negative", value);
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}
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}

‎core-java-modules/core-java-collections-4/src/test/java/com/baeldung/multipletypesinmap/MultipleTypesInMapUnitTest.java‎

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package com.baeldung.multipletypesinmap;
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import com.baeldung.collections.mulipletypesinmap.DynamicTypeValue;
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import com.baeldung.collections.mulipletypesinmap.InstantTypeValue;
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import com.baeldung.collections.mulipletypesinmap.IntArrayTypeValue;
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import com.baeldung.collections.mulipletypesinmap.IntegerTypeValue;
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import org.junit.jupiter.api.Test;
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import java.time.Instant;
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import java.time.ZoneId;
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import java.time.format.DateTimeFormatter;
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import java.util.Arrays;
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import java.util.HashMap;
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import java.util.Map;
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import static org.assertj.core.api.Assertions.assertThat;
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class MultipleTypesInMapUnitTest {
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private static final DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")
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.withZone(ZoneId.systemDefault());
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private static final Integer intValue = 777;
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private static final int[] intArray = new int[]{2, 3, 5, 7, 11, 13};
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private static final Instant instant = Instant.now();
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private static final String KEY_INT = "E1 (Integer)";
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private static final String KEY_INT_ARRAY = "E2 (IntArray)";
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private static final String KEY_INSTANT = "E3 (Instant)";
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@Test
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void givenThreeTypes_whenUsingRawMap_thenPrintDescription() {
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Map<String, Object> rawMap = new HashMap<>();
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rawMap.put(KEY_INT, intValue);
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rawMap.put(KEY_INT_ARRAY, intArray);
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rawMap.put(KEY_INSTANT, instant);
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rawMap.forEach((k, v) -> {
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if (v instanceof Integer) {
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Integer theV = (Integer) v;
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String desc = String.format("The value is a %s integer: %d", theV > 0 ? "positive" : "negative", theV);
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System.out.println(k + " -> " + desc);
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assertThat(k).isEqualTo(KEY_INT);
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assertThat(desc).isEqualTo("The value is a positive integer: 777");
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} else if (v instanceof int[]) {
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int[] theV = (int[]) v;
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String desc = String.format("The value is an array of %d integers: %s", theV.length, Arrays.toString(theV));
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System.out.println(k + " -> " + desc);
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assertThat(k).isEqualTo(KEY_INT_ARRAY);
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assertThat(desc).isEqualTo("The value is an array of 6 integers: [2, 3, 5, 7, 11, 13]");
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} else if (v instanceof Instant) {
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Instant theV = (Instant) v;
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String desc = String.format("The value is an instant: %s", FORMATTER.format(theV));
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System.out.println(k + " -> " + desc);
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assertThat(k).isEqualTo(KEY_INSTANT);
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assertThat(desc).matches("^The value is an instant: \\d{4}-\\d{2}-\\d{2} \\d{2}:\\d{2}:\\d{2}");
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} else {
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throw new IllegalStateException("Unknown Type found.");
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}
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});
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}
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@Test
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void givenThreeTypes_whenUsingAnInterface_thenPrintDescription() {
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Map<String, DynamicTypeValue> theMap = new HashMap<>();
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theMap.put(KEY_INT, new IntegerTypeValue(intValue));
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theMap.put(KEY_INT_ARRAY, new IntArrayTypeValue(intArray));
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theMap.put(KEY_INSTANT, new InstantTypeValue(instant));
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theMap.forEach((k, v) -> System.out.println(k + " -> " + v.valueDescription()));
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assertThat(theMap.get(KEY_INT).valueDescription()).isEqualTo("The value is a positive integer: 777");
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assertThat(theMap.get(KEY_INT_ARRAY).valueDescription()).isEqualTo("The value is an array of 6 integers: [2, 3, 5, 7, 11, 13]");
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assertThat(theMap.get(KEY_INSTANT).valueDescription()).matches("^The value is an instant: \\d{4}-\\d{2}-\\d{2} \\d{2}:\\d{2}:\\d{2}");
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}
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}

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