getting TreeSet object from Object variable

Question

I've a Object val with values [0,2,4,5,9], actually these values are been created from TreeSet like as shown below

TreeSet ts=new TreeSet ();
ts.add(0);
ts.add(2);
ts.add(4);
ts.add(5);
ts.add(9);

System.out.println(ts);

Output

[0,2,4,5,9]

i'm passing the output as string from server to client side

in the client side i 've

Object obj="[0,2,4,5,9]";

Can anyone please tell me how to convert the object values [0,2,4,5,9] to TreeSet Object so that i can iterate the values

Answer 1

You can send the treeset value back to the client in the form of JSONArray. I would recommend you to look into org.json package to easily do these kind of client and server interaction.

Note : JSON is light-weight data interchange format than xml. Latest browsers support json as a defacult standard. if you further want to go for string based value, you have to make use of javascript function to split the values and make use of them

Answer 2

how to convert the object values [0,2,4,5,9] to TreeSet Object so that i can iterate the values

Following is the way to convert object values to TreeSet,

 Object obj="[0,2,4,5,9]";

 String[] arr=obj.toString().substring(1, obj.toString().length()-1).split(",");

 TreeSet ts=new TreeSet(Arrays.asList(arr));

Answer 3

Since class AbstractCollection implement toString() method, like,

 /**
 * Returns a string representation of this collection.  The string
 * representation consists of a list of the collection's elements in the
 * order they are returned by its iterator, enclosed in square brackets
 * (<tt>"[]"</tt>).  Adjacent elements are separated by the characters
 * <tt>", "</tt> (comma and space).  Elements are converted to strings as
 * by <tt>String.valueOf(Object)</tt>.<p>
 *
 * This implementation creates an empty string buffer, appends a left
 * square bracket, and iterates over the collection appending the string
 * representation of each element in turn.  After appending each element
 * except the last, the string <tt>", "</tt> is appended.  Finally a right
 * bracket is appended.  A string is obtained from the string buffer, and
 * returned.
 * 
 * @return a string representation of this collection.
 */
public String toString() {
StringBuffer buf = new StringBuffer();
buf.append("[");

    Iterator<E> i = iterator();
    boolean hasNext = i.hasNext();
    while (hasNext) {
        E o = i.next();
        buf.append(o == this ? "(this Collection)" : String.valueOf(o));
        hasNext = i.hasNext();
        if (hasNext)
            buf.append(", ");
    }

buf.append("]");
return buf.toString();
}

That's why you get get a string like, [0,2,4,5,9], when you are trying to print TreeSet directly.

To he contrary, if you have String like [0,2,4,5,9],

You can remove the characters, including [ and ]. and then using String.split(",") method to put the values into an string array.

And then use new TreeSet(Arrays.asList(stringArray)); to convert the values into TreeSet object.

Answer 4

For example: You have the String value of TreeSet in below variable

var str = "[0,2,4,5,9]";
str =  str.substring(1,str.length-1);

var res = str.split(","); // This gives you a array of the elements.