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BAEL-2969: Copying Sets in Java

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This commit is contained in:
codehunter34 2019-06-07 14:55:13 -04:00
parent a0282482bc
commit 858927c985
1 changed files with 41 additions and 51 deletions
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92
core-java-modules/core-java-collections-set/src/main/java/com/baeldung/set/CopySets.java
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@ -2,7 +2,6 @@ package com.baeldung.set;
import java.io.Serializable; import java.io.Serializable;
import java.util.HashSet; import java.util.HashSet;
import java.util.Objects;
import java.util.Set; import java.util.Set;
import java.util.stream.Collectors; import java.util.stream.Collectors;
@ -12,63 +11,54 @@ import com.google.gson.Gson;
public class CopySets { public class CopySets {
public static <T> Set<T> copyByConstructor(Set<T> original) { // Copy Constructor
Set<T> copy = new HashSet<>(original); public static <T> Set<T> copyByConstructor(Set<T> original) {
return copy; Set<T> copy = new HashSet<>(original);
} return copy;
}
public static <T> Set<T> copyBySetAddAll(Set<T> original) { // Set.addAll
Set<T> copy = new HashSet<>(); public static <T> Set<T> copyBySetAddAll(Set<T> original) {
copy.addAll(original); Set<T> copy = new HashSet<>();
return copy; copy.addAll(original);
} return copy;
}
public static <T> Set<T> copyBySetClone(HashSet<T> original) { // Set.clone
Set<T> copy = (Set<T>) original.clone(); public static <T> Set<T> copyBySetClone(HashSet<T> original) {
return copy; Set<T> copy = (Set<T>) original.clone();
} return copy;
}
public static <T> Set<T> copyByJson(Set<T> original) { // JSON
Gson gson = new Gson(); public static <T> Set<T> copyByJson(Set<T> original) {
String jsonStr = gson.toJson(original); Gson gson = new Gson();
Set<T> copy = gson.fromJson(jsonStr, Set.class); String jsonStr = gson.toJson(original);
Set<T> copy = gson.fromJson(jsonStr, Set.class);
return copy; return copy;
} }
public static <T extends Serializable> Set<T> copyByApacheCommonsLang(Set<T> original) { // Apache Commons Lang
Set<T> copy = new HashSet<>(); public static <T extends Serializable> Set<T> copyByApacheCommonsLang(Set<T> original) {
for (T item : original) { Set<T> copy = new HashSet<>();
copy.add((T) SerializationUtils.clone(item)); for (T item : original) {
} copy.add((T) SerializationUtils.clone(item));
return copy; }
} return copy;
}
public static <T> void copyByStreamsAPI(Set<T> original) { // Collectors.toSet
Set<T> copy1 = original.stream() public static <T extends Serializable> Set<T> copyByCollectorsToSet(Set<T> original) {
.collect(Collectors.toSet()); Set<T> copy = original.stream().collect(Collectors.toSet());
// Skip the first element return copy;
Set<T> copy2 = original.stream() }
.skip(1)
.collect(Collectors.toSet());
// Filter by comparing the types and attributes // Using Java 10
Set<T> copy3 = original.stream() public static <T> Set<T> copyBySetCopyOf(Set<T> original) {
.filter(f -> f.getClass() Set<T> copy = Set.copyOf(original);
.equals(Integer.class)) return copy;
.collect(Collectors.toSet()); }
// Null check in case of expecting null values
Set<T> copy4 = original.stream()
.filter(Objects::nonNull)
.collect(Collectors.toSet());
}
public static <T> Set<T> copyByJava8(Set<T> original) {
Set<T> copy = Set.copyOf(original);
return copy;
}
} }