Read elements across all PDF pages in Java

//---------------------------------------------------------------------------------------
// Copyright (c) 2001-2019 by PDFTron Systems Inc. All Rights Reserved.
// Consult legal.txt regarding legal and license information.
//---------------------------------------------------------------------------------------

package com.pdftron.android.pdfnetsdksamples.samples;

import com.pdftron.android.pdfnetsdksamples.OutputListener;
import com.pdftron.android.pdfnetsdksamples.PDFNetSample;
import com.pdftron.android.pdfnetsdksamples.R;
import com.pdftron.android.pdfnetsdksamples.util.Utils;
import com.pdftron.common.PDFNetException;
import com.pdftron.pdf.Element;
import com.pdftron.pdf.ElementReader;
import com.pdftron.pdf.PDFDoc;
import com.pdftron.pdf.PageIterator;
import com.pdftron.pdf.PathData;

import java.util.ArrayList;

public class ElementReaderTest extends PDFNetSample {

	private static OutputListener mOutputListener;

	private static ArrayList<String> mFileList = new ArrayList<>();

    public ElementReaderTest() {
        setTitle(R.string.sample_elementreader_title);
        setDescription(R.string.sample_elementreader_description);
    }

	@Override
	public void run(OutputListener outputListener) {
		super.run(outputListener);
		mOutputListener = outputListener;
		mFileList.clear();
		printHeader(outputListener);

        try    // Extract text data from all pages in the document
        {
            mOutputListener.println("-------------------------------------------------");
            mOutputListener.println("Sample 1 - Extract text data from all pages in the document.");
            mOutputListener.println("Opening the input pdf...");

            PDFDoc doc = new PDFDoc(Utils.getAssetTempFile(INPUT_PATH + "newsletter.pdf").getAbsolutePath());
            doc.initSecurityHandler();

            int pgnum = doc.getPageCount();

            PageIterator itr;
            ElementReader page_reader = new ElementReader();

            for (itr = doc.getPageIterator(); itr.hasNext(); )        //  Read every page
            {
                page_reader.begin(itr.next());
                ProcessElements(page_reader);
                page_reader.end();
            }

            //Close the open document to free up document memory sooner.
            doc.close();
            mOutputListener.println("Done.");
        } catch (Exception e) {
            mOutputListener.printError(e.getStackTrace());
        }

		for (String file : mFileList) {
			addToFileList(file);
		}
		printFooter(outputListener);
	}

    static void ProcessElements(ElementReader reader) throws PDFNetException {
        for (Element element = reader.next(); element != null; element = reader.next())    // Read page contents
        {
			switch (element.getType()) 
			{
				case Element.e_path:                 // Process path data...
				{
					PathData data = element.getPathData();
					byte[] operators = data.getOperators();
					double[] points = data.getPoints();
				}
				break;
				case Element.e_text:                // Process text strings...
				{
					String data = element.getTextString();
					mOutputListener.println(data); 
				}
				break;
				case Element.e_form:                // Process form XObjects
				{
					reader.formBegin();
					ProcessElements(reader);
					reader.end();
				}
				break;
			}
        }
    }

}