Question

I am trying to match within a selection in a JTextArea and I am using Matcher.region() to define the boundary of my match:

JTextComponent t;

Pattern p = Pattern.compile("string", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE);
Matcher m = p.matcher(t.getText()).region(t.getSelectionStart(), t.getSelectionEnd());
m.useAnchoringBounds(false);

if(m.find()) {
  System.out.println("Found match from " + m.start() + " to " + m.end());
}
else {
  System.out.println("No match found");
}

The above works as expected and it will find the first match within the region – if no match is found then it doesn’t find a match.

However, I am trying to loop through the matches within the region (search and replace type function) and if I specify a start position to find() that is within the region then it matches outside of the region:

int cPos = m.regionStart();
if (m.find(cPos) || m.find(m.regionStart())) {
  System.out.println("Found match from " + m.start() + " to " + m.end());
  cPos = m.end();
}
else {
  System.out.println("No match found");
}

Is this a bug or am I breaking the region if I specify a start position – even if it is contained within the region?

Answer 1

From the Javadoc:

public boolean find(int start)

Resets this matcher and then […]

(emphasis mine)