[Q#19452238][A#19452417] User will input some filter criteria -- how can I turn it into a regular expression for String.match

https://stackoverflow.com/q/19452238

I have a program where the user will enter a string such as PropertyA = "abc_*" and I need to have the asterisk match any character. In my code, I'm grabbing the property value and replacing PropertyA with the actual value. For instance, it could be abc_123. I also pull out the equality symbol into a variable. It should be able to cover this type of criteria PropertyB = 'cba' PropertyC != '*-this' valueFromHeader is the lefthand side and value is the righthand side. EDIT: The existing code had this type of replacement for regular expressions It doesn't like the underscore here… It doesn't like the underscore…

Answer

https://stackoverflow.com/a/19452417

Replace * with .*.. This won't work if your value contain +,? since they all have special meaning in regex.Escape them if their are any..

APIzation

value=value.replace("*",".*");//replace  * with .*

package com.stackoverflow.api;

public class Human19452417 {

  public static String applyFilterCriteria(String value) {
    final String ESC = "\\$1";
    final String NON_ALPHA = "([^A-Za-z0-9@])";
    final String WILD = "*";
    final String WILD_RE_TEMP = "@";
    final String WILD_RE = ".*";
    value = value.replace(WILD, WILD_RE_TEMP);
    value = value.replaceAll(NON_ALPHA, ESC);
    value = value.replace(WILD_RE_TEMP, WILD_RE);
    value = value.replace("*", ".*"); // replace  * with .*
    return value;
  }
}

package com.stackoverflow.api;

/**
 * User will input some filter criteria -- how can I turn it into a regular expression for String.match
 *
 * @author APIzator
 * @see <a href="https://stackoverflow.com/a/19452417">https://stackoverflow.com/a/19452417</a>
 */
public class APIzator19452417 {

  public static void inputCriterion(String value) throws Exception {
    // replace  * with .*
    value = value.replace("*", ".*");
  }
}