Stirling-PDF/src/main/java/stirling/software/SPDF/pdf/TextFinder.java

package stirling.software.SPDF.pdf;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.text.PDFTextStripper;
import org.apache.pdfbox.text.TextPosition;

import stirling.software.SPDF.model.PDFText;

public class TextFinder extends PDFTextStripper {

	private final String searchText;
	private final boolean useRegex;
	private final boolean wholeWordSearch;
	private final List<PDFText> textOccurrences = new ArrayList<>();

	public TextFinder(String searchText, boolean useRegex, boolean wholeWordSearch) throws IOException {
	    this.searchText = searchText.toLowerCase();
	    this.useRegex = useRegex;
	    this.wholeWordSearch = wholeWordSearch;
	    setSortByPosition(true);
	}

	private List<Integer> findOccurrencesInText(String searchText, String content) {
	    List<Integer> indexes = new ArrayList<>();
	    Pattern pattern;

	    if (useRegex) {
	        // Use regex-based search
	        pattern = wholeWordSearch 
	            ? Pattern.compile("(\\b|_|\\.)" + searchText + "(\\b|_|\\.)") 
	            : Pattern.compile(searchText);
	    } else {
	        // Use normal text search
	        pattern = wholeWordSearch 
		            ? Pattern.compile("(\\b|_|\\.)" + Pattern.quote(searchText) + "(\\b|_|\\.)") 
		    	            : Pattern.compile(Pattern.quote(searchText));
	    }

	    Matcher matcher = pattern.matcher(content);
	    while (matcher.find()) {
	        indexes.add(matcher.start());
	    }
	    return indexes;
	}
	
	@Override
	protected void writeString(String text, List<TextPosition> textPositions) {
	    for (Integer index : findOccurrencesInText(searchText, text.toLowerCase())) {
	        if (index + searchText.length() <= textPositions.size()) {
	            // Initial values based on the first character
	            TextPosition first = textPositions.get(index);
	            float minX = first.getX();
	            float minY = first.getY();
	            float maxX = first.getX() + first.getWidth();
	            float maxY = first.getY() + first.getHeight();

	            // Loop over the rest of the characters and adjust bounding box values
	            for (int i = index; i < index + searchText.length(); i++) {
	                TextPosition position = textPositions.get(i);
	                minX = Math.min(minX, position.getX());
	                minY = Math.min(minY, position.getY());
	                maxX = Math.max(maxX, position.getX() + position.getWidth());
	                maxY = Math.max(maxY, position.getY() + position.getHeight());
	            }

	            textOccurrences.add(new PDFText(
	                    getCurrentPageNo() - 1,
	                    minX,
	                    minY,
	                    maxX,
	                    maxY,
	                    text
	            ));
	        }
	    }
	}

	public List<PDFText> getTextLocations(PDDocument document) throws Exception {
		this.getText(document);
		System.out.println("Found " + textOccurrences.size() + " occurrences of '" + searchText + "' in the document.");

		return textOccurrences;
	}

}