Java

Check if Integer Exists at JSON Path

Demonstrates how to get an integer value at a JSON path, and how to check to see if it exists. Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean success = false;

    CkJsonObject json = new CkJsonObject();

    //  First build simple JSON..
    json.UpdateInt("test.abc",100);

    json.put_EmitCompact(false);
    System.out.println(json.emit());

    //  This is our JSON:
    //  {
    //    "test": {
    //      "abc": 100,
    //    }
    //  }

    String path = "test.notHere";

    //  The call to IntOf will return 0, because it's not present.
    //  But how do we know if it really was present, and the value was truly 0?
    int val = json.IntOf(path);
    System.out.println("val = " + val);

    //  We cannot use LastMethodSuccess because LastMethodSuccess only applies
    //  to methods that:
    //  - return a string
    //  - return a new Chilkat object, binary bytes, or a date/time.
    //  - returns a boolean status where true = success and false = failed.
    //  - returns an integer where failure is defined by a return value less than zero.
    //  The IntOf method fits none of these requirements, and therefore the LastMethodSuccess 
    //  is not a valid indicator..
    boolean wasFound = json.get_LastMethodSuccess();
    System.out.println("wasFound = " + wasFound + " (not a valid indicator)");

    //  Instead, if the returned value is 0, we can double-check to see if the member was truly there..
    if (val == 0) {
        wasFound = json.HasMember(path);
        System.out.println("wasFound = " + wasFound);
        if (wasFound == true) {
            System.out.println("The value was present and is 0.");
            }
        else {
            System.out.println("no member is present at test.notHere");
            }

        }
    else {
        System.out.println("val = " + val);
        }

    //  Alternatively, you could check to see if the member exists beforehand..
    if (json.HasMember(path) == true) {
        System.out.println("val = " + json.IntOf(path));
        }
    else {
        System.out.println("no member at " + path);
        }
  }
}