Search PDF files for text 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.Action;
import com.pdftron.pdf.Highlights;
import com.pdftron.pdf.PDFDoc;
import com.pdftron.pdf.Page;
import com.pdftron.pdf.Rect;
import com.pdftron.pdf.TextSearch;
import com.pdftron.pdf.TextSearchResult;
import com.pdftron.sdf.SDFDoc;

import java.util.ArrayList;

public class TextSearchTest extends PDFNetSample {

	private static OutputListener mOutputListener;

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

    public TextSearchTest() {
        setTitle(R.string.sample_textsearch_title);
        setDescription(R.string.sample_textsearch_description);
    }

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

        try {
            PDFDoc doc = new PDFDoc(Utils.getAssetTempFile(INPUT_PATH + "credit card numbers.pdf").getAbsolutePath());
            doc.initSecurityHandler();

            TextSearch txt_search = new TextSearch();
            int mode = TextSearch.e_whole_word | TextSearch.e_page_stop;

            String pattern = "joHn sMiTh";

            //PDFDoc doesn't allow simultaneous access from different threads. If this
            //document could be used from other threads (e.g., the rendering thread inside
            //PDFView/PDFViewCtrl, if used), it is good practice to lock it.
            //Notice: don't forget to call doc.Unlock() to avoid deadlock.
            doc.lock();

            //call Begin() method to initialize the text search.
            txt_search.begin(doc, pattern, mode, -1, -1);

            int step = 0;

            //call Run() method iteratively to find all matching instances.
            while (true) {
                TextSearchResult result = txt_search.run();

                if (result.getCode() == TextSearchResult.e_found) {
                    if (step == 0) {
                        //step 0: found "John Smith"
                        //note that, here, 'ambient_string' and 'hlts' are not written to,
                        //as 'e_ambient_string' and 'e_highlight' are not set.
                        mOutputListener.println(result.getResultStr() + "'s credit card number is: ");

                        //now switch to using regular expressions to find John's credit card number
                        mode = txt_search.getMode();
                        mode |= TextSearch.e_reg_expression | TextSearch.e_highlight;
                        txt_search.setMode(mode);
                        String new_pattern = "\\d{4}-\\d{4}-\\d{4}-\\d{4}"; //or "(\\d{4}-){3}\\d{4}"
                        txt_search.setPattern(new_pattern);

                        step = step + 1;
                    } else if (step == 1) {
                        //step 1: found John's credit card number
                        mOutputListener.println("  " + result.getResultStr());

                        //note that, here, 'hlts' is written to, as 'e_highlight' has been set.
                        //output the highlight info of the credit card number
                        Highlights hlts = result.getHighlights();
                        hlts.begin(doc);
                        while (hlts.hasNext()) {
                            mOutputListener.println("The current highlight is from page: " + hlts.getCurrentPageNumber());
                            hlts.next();
                        }

                        //see if there is an AMEX card number
                        String new_pattern = "\\d{4}-\\d{6}-\\d{5}";
                        txt_search.setPattern(new_pattern);

                        step = step + 1;
                    } else if (step == 2) {
                        //found an AMEX card number
                        mOutputListener.println("\nThere is an AMEX card number:");
                        mOutputListener.println("  " + result.getResultStr());

                        //change mode to find the owner of the credit card; supposedly, the owner's
                        //name proceeds the number
                        mode = txt_search.getMode();
                        mode |= TextSearch.e_search_up;
                        txt_search.setMode(mode);
                        String new_pattern = "[A-z]++ [A-z]++";
                        txt_search.setPattern(new_pattern);

                        step = step + 1;
                    } else if (step == 3) {
                        //found the owner's name of the AMEX card
                        mOutputListener.println("Is the owner's name:");
                        mOutputListener.println("  " + result.getResultStr() + "?");

                        //add a link annotation based on the location of the found instance
                        Highlights hlts = result.getHighlights();
                        hlts.begin(doc);
                        while (hlts.hasNext()) {
                            Page cur_page = doc.getPage(hlts.getCurrentPageNumber());
                            double[] q = hlts.getCurrentQuads();
                            int quad_count = q.length / 8;
                            for (int i = 0; i < quad_count; ++i) {
                                //assume each quad is an axis-aligned rectangle
                                int offset = 8 * i;
                                double x1 = Math.min(Math.min(Math.min(q[offset + 0], q[offset + 2]), q[offset + 4]), q[offset + 6]);
                                double x2 = Math.max(Math.max(Math.max(q[offset + 0], q[offset + 2]), q[offset + 4]), q[offset + 6]);
                                double y1 = Math.min(Math.min(Math.min(q[offset + 1], q[offset + 3]), q[offset + 5]), q[offset + 7]);
                                double y2 = Math.max(Math.max(Math.max(q[offset + 1], q[offset + 3]), q[offset + 5]), q[offset + 7]);
                                com.pdftron.pdf.annots.Link hyper_link = com.pdftron.pdf.annots.Link.create(doc, new Rect(x1, y1, x2, y2), Action.createURI(doc, "http://www.pdftron.com"));
                                cur_page.annotPushBack(hyper_link);
                            }
                            hlts.next();
                        }
                        doc.save(Utils.createExternalFile("credit card numbers_linked.pdf", mFileList).getAbsolutePath(), SDFDoc.SaveMode.LINEARIZED, null);
                        break;
                    }
                } else if (result.getCode() == TextSearchResult.e_page) {
                    //you can update your UI here, if needed
                } else {
                    break;
                }
            }

            doc.unlock();
            doc.close();
        } catch (PDFNetException e) {
            mOutputListener.printError(e.getStackTrace());
        }

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

}