Change only specific text color + itext - itext

Question

I am using below code, which is changing the color of blue links to black from pdf:
void testAllRgbBlueToBlackConverter(String resourceName, String resultName) throws IOException {
System.out.printf("\nConverting '%s'.\n", resourceName);
try ( InputStream resource = getClass().getResourceAsStream(resourceName);
PdfReader pdfReader = new PdfReader(resource);
OutputStream result = new FileOutputStream(new File(RESULT_FOLDER, resultName));
PdfWriter pdfWriter = new PdfWriter(result);
PdfDocument pdfDocument = new PdfDocument(pdfReader, pdfWriter) ) {
PdfCanvasEditor editor = new AllRgbBlueToBlackConverter();
for (int i = 1; i <= pdfDocument.getNumberOfPages(); i++)
{
editor.editPage(pdfDocument, i);
}
}
}
class AllRgbBlueToBlackConverter extends PdfCanvasEditor {
#Override
protected void write(PdfCanvasProcessor processor, PdfLiteral operator, List<PdfObject> operands)
{
String operatorString = operator.toString();
if (RGB_SETTER_CANDIDATES.contains(operatorString) && operands.size() == 4) {
if (isBlue(operands.get(0), operands.get(1), operands.get(2))) {
PdfNumber number0 = new PdfNumber(0);
operands.set(0, number0);
operands.set(1, number0);
operands.set(2, number0);
}
}
super.write(processor, operator, operands);
}
boolean isBlue(PdfObject red, PdfObject green, PdfObject blue) {
if (red instanceof PdfNumber && green instanceof PdfNumber && blue instanceof PdfNumber) {
float r = ((PdfNumber)red).floatValue();
float g = ((PdfNumber)green).floatValue();
float b = ((PdfNumber)blue).floatValue();
return b > .5f && r < .9f*b && g < .9f*b;
}
return false;
}
final Set<String> RGB_SETTER_CANDIDATES = new HashSet<>(Arrays.asList("rg", "RG", "sc", "SC", "scn", "SCN"));
}
Can I restrict above code, in which i restrict that change color only when text is equal to "bla bla". Otherwise dont change color? This code changes the color of graph line as well, if there is any graph available in pdf.
I am using itext. If anyone have any code available in other library. Please share it with me. I am stuck on this since month. I want to change the color of specific text from blue to black.