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BAEL-2800: Moved core-java-collections-map to java-collections-maps-2

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This commit is contained in:
eric-martin
2019-04-24 22:53:09 -05:00
parent 9ba9b3d1fc
commit 156f9b6906
7 changed files with 16 additions and 89 deletions
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13
java-collections-maps-2/pom.xml
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@@ -36,6 +36,17 @@
<artifactId>colt</artifactId>
<version>${colt.version}</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>${commons-lang3.version}</version>
</dependency>
<dependency>
<groupId>org.assertj</groupId>
<artifactId>assertj-core</artifactId>
<version>${assertj.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
<properties>
@@ -43,6 +54,8 @@
<trove4j.version>3.0.2</trove4j.version>
<fastutil.version>8.1.0</fastutil.version>
<colt.version>1.2.0</colt.version>
<commons-lang3.version>3.8.1</commons-lang3.version>
<assertj.version>3.11.1</assertj.version>
</properties>
</project>

55
java-collections-maps-2/src/main/java/com/baeldung/map/CopyHashMap.java Normal file
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@@ -0,0 +1,55 @@
package com.baeldung.map;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.stream.Collectors;
import org.apache.commons.lang3.SerializationUtils;
public class CopyHashMap {
public static <String, Employee> HashMap<String, Employee> copyUsingConstructor(HashMap<String, Employee> originalMap) {
return new HashMap<String, Employee>(originalMap);
}
public static <String, Employee> HashMap<String, Employee> copyUsingClone(HashMap<String, Employee> originalMap) {
return (HashMap<String, Employee>) originalMap.clone();
}
public static <String, Employee> HashMap<String, Employee> copyUsingPut(HashMap<String, Employee> originalMap) {
HashMap<String, Employee> shallowCopy = new HashMap<String, Employee>();
Set<Entry<String, Employee>> entries = originalMap.entrySet();
for(Map.Entry<String, Employee> mapEntry: entries) {
shallowCopy.put(mapEntry.getKey(), mapEntry.getValue());
}
return shallowCopy;
}
public static <String, Employee> HashMap<String, Employee> copyUsingPutAll(HashMap<String, Employee> originalMap) {
HashMap<String, Employee> shallowCopy = new HashMap<String, Employee>();
shallowCopy.putAll(originalMap);
return shallowCopy;
}
public static <String, Employee> HashMap<String, Employee> copyUsingJava8Stream(HashMap<String, Employee> originalMap) {
Set<Entry<String, Employee>> entries = originalMap.entrySet();
HashMap<String, Employee> shallowCopy = (HashMap<String, Employee>) entries
.stream()
.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
return shallowCopy;
}
public static <String, Employee> HashMap<String, Employee> shallowCopy(HashMap<String, Employee> originalMap) {
return (HashMap<String, Employee>) originalMap.clone();
}
public static <String, Employee> HashMap<String, Employee> deepCopy(HashMap<String, Employee> originalMap) {
return SerializationUtils.clone(originalMap);
}
}

77
java-collections-maps-2/src/test/java/com/baeldung/map/CopyHashMapUnitTest.java Normal file
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@@ -0,0 +1,77 @@
package com.baeldung.map;
import static org.assertj.core.api.Assertions.assertThat;
import java.util.HashMap;
import java.util.Map;
import org.junit.Test;
import com.google.common.collect.ImmutableMap;
public class CopyHashMapUnitTest {
@Test
public void givenHashMap_whenShallowCopy_thenCopyisNotSameAsOriginal() {
HashMap<String, Employee> map = new HashMap<>();
Employee emp1 = new Employee("John");
Employee emp2 = new Employee("Norman");
map.put("emp1",emp1);
map.put("emp2",emp2);
HashMap<String, Employee> shallowCopy = CopyHashMap.shallowCopy(map);
assertThat(shallowCopy).isNotSameAs(map);
}
@Test
public void givenHashMap_whenShallowCopyModifyingOriginalObject_thenCopyShouldChange() {
HashMap<String, Employee> map = new HashMap<>();
Employee emp1 = new Employee("John");
Employee emp2 = new Employee("Norman");
map.put("emp1",emp1);
map.put("emp2",emp2);
HashMap<String, Employee> shallowCopy = CopyHashMap.shallowCopy(map);
emp1.setName("Johny");
assertThat(shallowCopy.get("emp1")).isEqualTo(map.get("emp1"));
}
@Test
public void givenHashMap_whenDeepCopyModifyingOriginalObject_thenCopyShouldNotChange() {
HashMap<String, Employee> map = new HashMap<>();
Employee emp1 = new Employee("John");
Employee emp2 = new Employee("Norman");
map.put("emp1",emp1);
map.put("emp2",emp2);
HashMap<String, Employee> deepCopy = CopyHashMap.deepCopy(map);
emp1.setName("Johny");
assertThat(deepCopy.get("emp1")).isNotEqualTo(map.get("emp1"));
}
@Test
public void givenImmutableMap_whenCopyUsingGuava_thenCopyShouldNotChange() {
Employee emp1 = new Employee("John");
Employee emp2 = new Employee("Norman");
Map<String, Employee> map = ImmutableMap.<String, Employee> builder()
.put("emp1",emp1)
.put("emp2",emp2)
.build();
Map<String, Employee> shallowCopy = ImmutableMap.copyOf(map);
assertThat(shallowCopy).isSameAs(map);
}
}

28
java-collections-maps-2/src/test/java/com/baeldung/map/Employee.java Normal file
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@@ -0,0 +1,28 @@
package com.baeldung.map;
import java.io.Serializable;
public class Employee implements Serializable{
private String name;
public Employee(String name) {
super();
this.name = name;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return this.name;
}
}