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

2019-04-24 22:53:09 -05:00
parent 9ba9b3d1fc
commit 156f9b6906
7 changed files with 16 additions and 89 deletions
--- a/java-collections-maps-2/src/main/java/com/baeldung/map/CopyHashMap.java
+++ b/java-collections-maps-2/src/main/java/com/baeldung/map/CopyHashMap.java
@@ -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);
+    }
+    
+}