Copy list to another list examples (#4725)

2018-07-16 03:41:08 -03:00
parent 61e6d9a3cd
commit f68615d772
4 changed files with 244 additions and 0 deletions
@@ -0,0 +1,73 @@
+package com.baeldung.list;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class CopyListService {
+
+    public List<Flower> copyListByConstructor(List<Flower> source) {
+        return new ArrayList<Flower>(source);
+    }
+
+    public List<Flower> copyListByConstructorAndEditOneFlowerInTheNewList(List<Flower> source) {
+        List<Flower> flowers = new ArrayList<>(source);
+        if(flowers.size() > 0) {
+            flowers.get(0).setPetals(flowers.get(0).getPetals() * 3);
+        }
+
+        return flowers;
+    }
+
+    public List<Flower> copyListByAddAllMethod(List<Flower> source) {
+        List<Flower> flowers = new ArrayList<>();
+        flowers.addAll(source);
+        return flowers;
+    }
+
+    public List<Flower> copyListByAddAllMethodAndEditOneFlowerInTheNewList(List<Flower> source) {
+        List<Flower> flowers = new ArrayList<>();
+        flowers.addAll(source);
+
+        if(flowers.size() > 0) {
+            flowers.get(0).setPetals(flowers.get(0).getPetals() * 3);
+        }
+
+        return flowers;
+    }
+
+    public List<Integer> copyListByCopyMethod(List<Integer> source, List<Integer> dest) {
+        Collections.copy(dest, source);
+        return dest;
+    }
+
+    public List<Flower> copyListByStream(List<Flower> source) {
+        return source.stream().collect(Collectors.toList());
+    }
+
+    public List<Flower> copyListByStreamAndSkipFirstElement(List<Flower> source) {
+        return source.stream().skip(1).collect(Collectors.toList());
+    }
+
+    public List<Flower> copyListByStreamWithFilter(List<Flower> source, Integer moreThanPetals) {
+        return source.stream().filter(f -> f.getPetals() > moreThanPetals).collect(Collectors.toList());
+    }
+
+    public List<Flower> copyListByStreamWithOptional(List<Flower> source) {
+        return Optional.ofNullable(source)
+                 .map(List::stream)
+                 .orElseGet(Stream::empty)
+                 .collect(Collectors.toList());
+    }
+
+    public List<Flower> copyListByStreamWithOptionalAndSkip(List<Flower> source) {
+        return Optional.ofNullable(source)
+                .map(List::stream)
+                .orElseGet(Stream::empty)
+                .skip(1)
+                .collect(Collectors.toList());
+    }
+}
@@ -0,0 +1,28 @@
+package com.baeldung.list;
+
+public class Flower {
+
+    private String name;
+    private int petals;
+
+    public Flower(String name, int petals) {
+        this.name = name;
+        this.petals = petals;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getPetals() {
+        return petals;
+    }
+
+    public void setPetals(int petals) {
+        this.petals = petals;
+    }
+}