Android™

Prevent JavaScript Infinite Loops

See more JavaScript Examples

Demonstrates how prevent infinite loops or prevent the JavaScript from running for a longer amount of time than allowed. Android™

// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    boolean success = false;

    // This is the JavaScript we'll run:

    // console.log('Starting infinite loop...'); while(true) {};

    CkStringBuilder sbScript = new CkStringBuilder();
    sbScript.Append("console.log('Starting infinite loop...'); while(true) {};");

    CkJs js = new CkJs();

    // Set a limit on the amount of time (in seconds) the script is allowed to run.
    // If the JavaScript takes longer than this amount of time, then Chilkat kills the script without crashing the host program.
    // The default value of TimeoutSeconds is 0, which indicates no limit.
    // For this example, set a limit of 2 seconds.
    js.put_TimeoutSeconds(2);

    CkJsonObject result = new CkJsonObject();
    result.put_EmitCompact(false);

    // Run the script..
    success = js.Eval(sbScript,result);
    if (success == false) {
        // Examine the result for an exception.
        Log.i(TAG, result.emit());

        // The result contains this:

        // 	{
        // 	  "exception": {
        // 	    "message": "interrupted - JavaScript exceeded the Chilkat.Js.TimeoutSeconds",
        // 	    "stack": [
        // 	      {
        // 	        "func": "<eval>",
        // 	        "file": "<input>",
        // 	        "line": 1,
        // 	        "col": 8
        // 	      }
        // 	    ]
        // 	  }
        // 	}

        // Also examine the LastErrorText.
        Log.i(TAG, js.lastErrorText());
        return;
        }

    // We should never get here..
    Log.i(TAG, "Succeeded.");
    Log.i(TAG, result.emit());

  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}