iSharkFly-Docs
/
java-tutorials
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Java Hashmap with different value types (#11495) 

* Java Hashmap with different value types

* some fixes according to review comments

* convert liveTest -> unitTest

* convert liveTest -> unitTest
This commit is contained in:
Kai Yuan 2021-12-01 01:17:36 +01:00 committed by GitHub
parent 0c859a7d49
commit 052eb565bc
5 changed files with 141 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
core-java-modules/core-java-collections-4/src/main/java/com/baeldung/collections/mulipletypesinmap/DynamicTypeValue.java Normal file
View File

@ -0,0 +1,5 @@
package com.baeldung.collections.mulipletypesinmap;
public interface DynamicTypeValue {
String valueDescription();
}

24
core-java-modules/core-java-collections-4/src/main/java/com/baeldung/collections/mulipletypesinmap/InstantTypeValue.java Normal file
View File

@ -0,0 +1,24 @@
package com.baeldung.collections.mulipletypesinmap;
import java.time.Instant;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
public class InstantTypeValue implements DynamicTypeValue {
private static DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")
.withZone(ZoneId.systemDefault());
private Instant value;
public InstantTypeValue(Instant value) {
this.value = value;
}
@Override
public String valueDescription() {
if (value == null) {
return "The value is null.";
}
return String.format("The value is an instant: %s", FORMATTER.format(value));
}
}

20
core-java-modules/core-java-collections-4/src/main/java/com/baeldung/collections/mulipletypesinmap/IntArrayTypeValue.java Normal file
View File

@ -0,0 +1,20 @@
package com.baeldung.collections.mulipletypesinmap;
import java.util.Arrays;
public class IntArrayTypeValue implements DynamicTypeValue {
private int[] value;
public IntArrayTypeValue(int[] value) {
this.value = value;
}
@Override
public String valueDescription() {
if (value == null) {
return "The value is null.";
}
return String.format("The value is an array of %d integers: %s", value.length, Arrays.toString(value));
}
}

17
core-java-modules/core-java-collections-4/src/main/java/com/baeldung/collections/mulipletypesinmap/IntegerTypeValue.java Normal file
View File

@ -0,0 +1,17 @@
package com.baeldung.collections.mulipletypesinmap;
public class IntegerTypeValue implements DynamicTypeValue {
private Integer value;
public IntegerTypeValue(Integer value) {
this.value = value;
}
@Override
public String valueDescription() {
if(value == null){
return "The value is null.";
}
return String.format("The value is a %s integer: %d", value > 0 ? "positive" : "negative", value);
}
}

75
core-java-modules/core-java-collections-4/src/test/java/com/baeldung/multipletypesinmap/MultipleTypesInMapUnitTest.java Normal file
View File

@ -0,0 +1,75 @@
package com.baeldung.multipletypesinmap;
import com.baeldung.collections.mulipletypesinmap.DynamicTypeValue;
import com.baeldung.collections.mulipletypesinmap.InstantTypeValue;
import com.baeldung.collections.mulipletypesinmap.IntArrayTypeValue;
import com.baeldung.collections.mulipletypesinmap.IntegerTypeValue;
import org.junit.jupiter.api.Test;
import java.time.Instant;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import static org.assertj.core.api.Assertions.assertThat;
class MultipleTypesInMapUnitTest {
private static final DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")
.withZone(ZoneId.systemDefault());
private static final Integer intValue = 777;
private static final int[] intArray = new int[]{2, 3, 5, 7, 11, 13};
private static final Instant instant = Instant.now();
private static final String KEY_INT = "E1 (Integer)";
private static final String KEY_INT_ARRAY = "E2 (IntArray)";
private static final String KEY_INSTANT = "E3 (Instant)";
@Test
void givenThreeTypes_whenUsingRawMap_thenPrintDescription() {
Map<String, Object> rawMap = new HashMap<>();
rawMap.put(KEY_INT, intValue);
rawMap.put(KEY_INT_ARRAY, intArray);
rawMap.put(KEY_INSTANT, instant);
rawMap.forEach((k, v) -> {
if (v instanceof Integer) {
Integer theV = (Integer) v;
String desc = String.format("The value is a %s integer: %d", theV > 0 ? "positive" : "negative", theV);
System.out.println(k + " -> " + desc);
assertThat(k).isEqualTo(KEY_INT);
assertThat(desc).isEqualTo("The value is a positive integer: 777");
} else if (v instanceof int[]) {
int[] theV = (int[]) v;
String desc = String.format("The value is an array of %d integers: %s", theV.length, Arrays.toString(theV));
System.out.println(k + " -> " + desc);
assertThat(k).isEqualTo(KEY_INT_ARRAY);
assertThat(desc).isEqualTo("The value is an array of 6 integers: [2, 3, 5, 7, 11, 13]");
} else if (v instanceof Instant) {
Instant theV = (Instant) v;
String desc = String.format("The value is an instant: %s", FORMATTER.format(theV));
System.out.println(k + " -> " + desc);
assertThat(k).isEqualTo(KEY_INSTANT);
assertThat(desc).matches("^The value is an instant: \\d{4}-\\d{2}-\\d{2} \\d{2}:\\d{2}:\\d{2}");
} else {
throw new IllegalStateException("Unknown Type found.");
}
});
}
@Test
void givenThreeTypes_whenUsingAnInterface_thenPrintDescription() {
Map<String, DynamicTypeValue> theMap = new HashMap<>();
theMap.put(KEY_INT, new IntegerTypeValue(intValue));
theMap.put(KEY_INT_ARRAY, new IntArrayTypeValue(intArray));
theMap.put(KEY_INSTANT, new InstantTypeValue(instant));
theMap.forEach((k, v) -> System.out.println(k + " -> " + v.valueDescription()));
assertThat(theMap.get(KEY_INT).valueDescription()).isEqualTo("The value is a positive integer: 777");
assertThat(theMap.get(KEY_INT_ARRAY).valueDescription()).isEqualTo("The value is an array of 6 integers: [2, 3, 5, 7, 11, 13]");
assertThat(theMap.get(KEY_INSTANT).valueDescription()).matches("^The value is an instant: \\d{4}-\\d{2}-\\d{2} \\d{2}:\\d{2}:\\d{2}");
}
}