Transferring information from a Java file to AJAX

Question

Transferring information from a Java file to AJAX

I have a Java class that prints progress as 1%, 2%, 3% of a process. Now, I am looking to utilize AJAX requests to read this progress and update it continuously on the webpage. Unfortunately, I cannot convert the Java file into a servlet since it is being used as a scriptlet by Jasper.

The scriptlet code is as follows:

public void afterDetailEval() throws JRScriptletException{
     count = (Integer) this.getVariableValue("count"); 
     out.println(count);
     Thread.sleep(200); 
}

How can I retrieve the data printed by Java through an AJAX request?

Any assistance on this matter would be highly appreciated!

javascript java ajax jsp

Answer 1

Answer №1

How can you create your own scriptlet? If you have a class like this in mind:

public class YourScriptlet extends JRDefaultScriptlet {
    public void afterDetailEval() throws JRScriptletException {
        // Add your code here
    }
}

You can enhance it by adding a constructor and a private member for another object that can store data outside of the Jasper context, like this:

An example object to keep track of certain values:

public class YourInfoObject {
    private final AtomicInteger count = new AtomicInteger();
    public int increment() {
        return this.count.incrementAndGet();
    }
    public int get() {
        return this.count.intValue();
    }
    public void set(int value) {
        this.count.set(value);
    }
}

Your updated scriptlet class with a constructor:

public class YourScriptlet extends JRDefaultScriptlet {
    private final YourInfoObject obj;
    public YourScriptlet(YourInfoObject obj) {
        this.obj = obj;
    }
    public void afterDetailEval() throws JRScriptletException {
        // Add your code here
        obj.set(count);
    }
}

Now, from anywhere else (e.g., a Servlet with a reference to your object), you can access the stored value.

Answer 2

How can you create your own scriptlet? If you have a class like this in mind:

public class YourScriptlet extends JRDefaultScriptlet {
    public void afterDetailEval() throws JRScriptletException {
        // Add your code here
    }
}

You can enhance it by adding a constructor and a private member for another object that can store data outside of the Jasper context, like this:

An example object to keep track of certain values:

public class YourInfoObject {
    private final AtomicInteger count = new AtomicInteger();
    public int increment() {
        return this.count.incrementAndGet();
    }
    public int get() {
        return this.count.intValue();
    }
    public void set(int value) {
        this.count.set(value);
    }
}

Your updated scriptlet class with a constructor:

public class YourScriptlet extends JRDefaultScriptlet {
    private final YourInfoObject obj;
    public YourScriptlet(YourInfoObject obj) {
        this.obj = obj;
    }
    public void afterDetailEval() throws JRScriptletException {
        // Add your code here
        obj.set(count);
    }
}

Now, from anywhere else (e.g., a Servlet with a reference to your object), you can access the stored value.

Transferring information from a Java file to AJAX

Answer №1

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