compare org.codehaus.jettison.json.JSONArray without regard to order

Question

I've got 2 JSONArray full of integers.

I want to compare them for equal content without regard for order.

So:

[1, 2] == [1, 2] TRUE [1, 2] == [2, 1] TRUE

JSONArray has

public boolean equals(Object o) 

but it returns FALSE for [1, 2] == [2, 1]

So, I rolled my own:

public boolean isEqual(JSONArray inputJsonArray, 
                       JSONArray outputJsonArray) throws JSONException{
    boolean equal=true, done;
    int idx = 0;      

    if (inputJsonArray.length() == outputJsonArray.length()){

        //make sure all elements in input array are in output array
        done=false;
        while (!done){
            if(idx >= inputJsonArray.length()){
               done=true;
            }
            else if (isIntInJsonArray(outputJsonArray,
                                      inputJsonArray.getInt(idx)) == false){
                     equal = false;
                     done=true;
            }
            else{
                     idx ++;
            }

        }

        if (equal){

            //make sure all elements in output array are in input array
            done=false;
            while (!done){
                  if (idx >= outputJsonArray.length()){
                       done=true;
                  }
                  else if (isIntInJsonArray(inputJsonArray,
                                         outputJsonArray.getInt(idx)) == false){

                            equal = false;
                            done=true;
                  }
                  else{
                            idx++;
                  }

            }          
        }           
    }
    else{
            equal = false;
    }

    return equal;

}

Basically, I check if both JSONArrays are the same length. If they are then I make sure every element in the outputJsonArray is in the inputJsonArray and vice versa. The workhorse method that does this is:

private boolean isIntInJsonArray(JSONArray inputJsonArray, int mInt) throws JSONException{
    boolean found=false, done=false;
    int idx = 0;

    while (!done){
            if(idx >= inputJsonArray.length()){
               done=true;
            }
            else if (inputJsonArray.getInt(idx) == mInt){
               found = true;
               done=true;
            }
            else{
               idx ++;
            }              
    }

    return(found);
 }   

This strikes me like an awful lot of code. Does anyone know if there is a simpler way to do this?

Answer 1

Convert the arrays to JSONObject then use its equals method.

JSONArray arr1 = new JSONArray();
JSONArray arr2 = new JSONArray();

arr1.put(1);
arr1.put(2);
arr1.put(3);
arr1.put(4);
arr1.put(5);

arr2.put(2);
arr2.put(1);
arr2.put(3);
arr2.put(5);
arr2.put(4);

JSONObject o1 = arr1.toJSONObject(arr1);
JSONObject o2 = arr2.toJSONObject(arr2);

System.out.println(o1.equals(o2)); //true

Looking at the source code of JSONObject, it is using its underlying map to check equality.

@Override
public boolean equals(Object obj) {
   if (obj instanceof JSONObject) {
      return myHashMap.equals(((JSONObject)obj).myHashMap);
   } else {
      return false;
   }
}

The equals implementation of underlying map is disregarding the order of its content

public boolean equals(Object o) {
    if (o == this)
        return true;

    if (!(o instanceof Map))
        return false;
    Map<K,V> m = (Map<K,V>) o;
    if (m.size() != size())
        return false;

    try {
        Iterator<Entry<K,V>> i = entrySet().iterator();
        while (i.hasNext()) {
            Entry<K,V> e = i.next();
            K key = e.getKey();
            V value = e.getValue();
            if (value == null) {
                if (!(m.get(key)==null && m.containsKey(key)))
                    return false;
            } else {
                if (!value.equals(m.get(key)))
                    return false;
            }
        }
    } catch (ClassCastException unused) {
        return false;
    } catch (NullPointerException unused) {
        return false;
    }

    return true;
}