Returns a defensive copy for either Collections, Maps or Arrays - Java java.util

Java examples for java.util:Collection to Array

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Description

Returns a defensive copy for either Collections, Maps or Arrays

Demo Code


import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

public class Main{
    public static void main(String[] argv){
        Object object = "java2s.com";
        System.out.println(defensiveCopy(object));
    }//from  w w  w . j a  va  2 s  .  c o  m
    /**
     * Returns a defensive copy for either Collections, Maps or Arrays
     */
    @SuppressWarnings("unchecked")
    public static <T> T defensiveCopy(final Object object) {
        if (object == null) {
            return null;
        } else if (object instanceof Set) {
            return (T) new LinkedHashSet<Object>((Set<?>) object);
        } else if (object instanceof Collection) {
            return (T) new ArrayList<Object>((Collection<?>) object);
        } else if (object instanceof Properties) {
            final Properties properties = new SortedProperties();
            properties.putAll((Properties) object);
            return (T) properties;
        } else if (object instanceof Map<?, ?>) {
            return (T) new LinkedHashMap<Object, Object>((Map<?, ?>) object);
        } else if (object.getClass().isArray()) {
            final int length = Array.getLength(object);
            final Object newArray = Array.newInstance(object.getClass()
                    .getComponentType(), length);
            System.arraycopy(object, 0, newArray, 0, length);
            return (T) newArray;
        } else {
            return (T) object;
        }
    }
}

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