How to invoke a parameter to a void class?

Question

I am dealing with the text extraction from pdf. To this end I wrote my own text extraction strategy. I have one dynamic class and within this class i invoke text extraction strategy. However, when i introduce some parameters to my dynamic class i cannot use them within strategy class. To be clear i am adding my code template below.

My question is briefly, is it possible to invoke parameter unq showing up in "get_intro" class, from renderText? Or other way around, can a variable or parameter created inside the "renderText" class be invoked in the "get_intro"?

public class trial {

public trial(){}

    public  Boolean get_intro(String pdf, String unq){

    try { ....

            for (int j = 1; j <= 3; j++) {
            out.println(PdfTextExtractor.getTextFromPage(reader, j, semTextExtractionStrategy));
            }
...} catch (Exception e) {
        e.printStackTrace();
    }

semTextExtractionStrategy part:

public class SemTextExtractionStrategy implements TextExtractionStrategy {
    @Override
public void beginTextBlock() {
}

@Override
public void renderText(TextRenderInfo renderInfo) {                       

    text = renderInfo.getText();...}

    @Override
public void endTextBlock() {
}

@Override
public void renderImage(ImageRenderInfo renderInfo) {
}

@Override
public String getResultantText() {
    //return text;
    return main;
}
}

Answer 1

One could consider the following problematic solution:

public abstract class DefaultTextExtractionStrategy<D>
       implements TextExtractionStrategy {
    protected D documentInfo;

    public final void setDocumentInfo(D documentInfo) {
        this.documentInfo = documentInfo;
    }

public class SemTextExtractionStrategy extends DefaultTextExtractionStrategy<SemDoc> {
    @Override
    public void beginTextBlock() {
        documentInfo ...
    }

public class SemDoc {
    public String unq:
}

And in get_intro:

       SemDoc semDoc = new SemDoc();
       semDoc.unq = unq;
       semTextExtractionStrategy.setDocumentInfo(semDoc);
       out.println(PdfTextExtractor.getTextFromPage(reader, j, semTextExtractionStrategy));

The problem is that you want to pass some context class on calling the entry function (like ActionEvent or such). But by its name a strategy class probably is a stateless singleton. In the above solution you would need to instantiate from a Class<TextExctractionStrategy>, Class<D> a new strategy instance. Or like in the MouseAdapter class pass the same event class parameter to every method.

This smells of "over-designing" or a skewed pattern application.

As we are on the brink of Java 8 lambdas, you might even consider a "backport" of a design with lambdas.

But for the moment I would go with adding a generic D textExtractionContext to every called function, if the API is not for an external library.