CODEWITHSUNDEEP
multithreadingdjnativeswingjdic
AnoyLi
AnoyLi

Reputation: 3

how to drive DJ NativeSwing thread separately from my own thread

Nowadays, I am working on a java swing application using DJ NativeSwing as my embed browser to do something automatic work. The scenario of my application is that a user click start button and the embed browser auto click some position of the current page and then redirect to another one and then execute some other operations like click or something other. Now here is my solution. First, I will define a webbrowser class (extends JWebBrowser) and webbrowser listener class (implements WebBrowserListener), which represents a webbrowser and contains loadingProgressChanged, windowOpening and so on separately. Second, I define a thread class to do some logic computing and execute my browser operations as mentioned above by webbrowser.executeJavascript. At last, I add mouseListener for start and stop button to start or stop the task. When I open my application, the JFrame add the browser and its listener class. I click the start button, the browser works and will click the target position as I expected and then the page will redirect to another one. As we all know, js code can’t be executed until the page was loaded completely. So I set a global flag to check whether the page has loaded completely or not in loadingProgressChanged (code:if(e.getWebBrowser().getLoadingProgress() == 100)globalflag = true;) within webbrowser listener class. And in the thread class, I use code( while(globalflag == false){Thread.sleep(500);}) after first click to detect if the current page was loaded completely. However, when browser first click the target position and the page redirects successfully, I find that the current page has changed but blocked. After some debugging, I find it. In my thread class, browser will execute js code by webbrowser.executeJavascript("document.getElementById(‘target’).click();") to click the target position and then java code (while(globalflag == false){Thread.sleep(500);}) to detect if the current page was loaded completely and then execute some other java code. I find that the globalflag will never change and the current page’s loadingProgressChanged listener will never work because the java code (while(globalflag == false)). Because after I remove all java code after the first webbrowser.executeJavascript("document.getElementById(‘target’).click();"), the current page’s loadingProgressChanged listener works and the page was not blocked. With the DJ NativeSwing demo, I could execute my js in the loadingProgressChanged. However, I want to do a series of operations with my browser and also want to stop the task whenever need. So, I prefer to my solution for my demand rather than the provided one by demo. So, I wonder that after webbrowser.executeJavascript the DJ NativeSwing thread will wait my thread? And, in my software architecture, does anyone could have any suggestions? Thanks a lot. Any suggestion is appreciated! PS.my application works fine with jdic-0.9.5, but it supports IE7 only.

I paste my code here to demonstrate my problem: After I click the start button in JFrame, I will new a thread as follow

public class MyVisit implements Runnable{
  private void doClick1(){
    webbrowser.executeJavascript("document.getElementById('n').value='test'");
    webbrowser.executeJavascript("document.getElementById('f').submit()");
  }
  public void run() {
        globalFlag=false;
	webbrowser.executeJavascript("document.getElementById(‘t’).click();") ;
	while(!globalFlag){
	   Thread.sleep(500);
        }
	this.doClick1();
  }
} 

listener:


public class MyListener implements WebBrowserListener {
        …
	public void loadingProgressChanged(WebBrowserEvent e) {
		if (e.getWebBrowser().getLoadingProgress() == 100) {
			globalFlag=true;	
                }
	}
}

Upvotes: -1

Views: 176

Answers (1)

Christopher Deckers
Christopher Deckers

Reputation: 311

DJ Native Swing enforces the Swing approach to threading: manipulate the components in the AWT Event Dispatch thread (a.k.a. UI thread). But also, do not block that thread, because listeners are triggered in that thread too. So, you should not have a "while" loop in the UI thread, but should instead spawn a new thread. I hope your global variable is volatile, or AtomicBoolean or all accesses to it protected by synchronized block, otherwise you might have interesting threading side effects.

Upvotes: 1

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