package edu.stanford.nlp.io;
import java.io.File;
import java.io.FileFilter;
/**
* Implements a file filter that examines a number in a filename to
* determine acceptance. This is useful for wanting to process ranges
* of numbered files in collections where each file has some name, part
* of which is alphabetic and constant, and part of which is numeric.
* The test is evaluated based on the rightmost natural number found in
* the filename string. (It only looks in the final filename, not in other
* components of the path.) Number ranges are inclusive.
*
* @author Christopher Manning
* @version 2000/12/29
*/
public class NumberRangeFileFilter implements FileFilter {
private int minimum;
private int maximum;
private boolean recursively;
/**
* Sets up a NumberRangeFileFilter by specifying the range of numbers
* to accept, and whether to also traverse
* folders for recursive search.
*
* @param min The minimum number file to accept (checks >= this one)
* @param max The maximum number file to accept (checks <= this one)
* @param recurse go into folders
*/
public NumberRangeFileFilter(int min, int max, boolean recurse) {
minimum = min;
maximum = max;
recursively = recurse;
}
/**
* Checks whether a file satisfies the number range selection filter.
*
* @param file The file
* @return true if the file is within the range filtered for
*/
public boolean accept(File file) {
if (file.isDirectory()) {
return recursively;
} else {
String filename = file.getName();
int k = filename.length() - 1;
char c = filename.charAt(k);
while (k >= 0 && (c < '0' || c > '9')) {
k--;
if (k >= 0) {
c = filename.charAt(k);
}
}
if (k < 0) {
return false;
}
int j = k;
c = filename.charAt(j);
while (j >= 0 && (c >= '0' && c <= '9')) {
j--;
if (j >= 0) {
c = filename.charAt(j);
}
}
j++;
k++;
String theNumber = filename.substring(j, k);
int number = Integer.parseInt(theNumber);
return (number >= minimum) && (number <= maximum);
}
}
}
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