public static void main(String[] args)
 {
 	PathManager pathManager = new PathManager();
 	pathManager.addDeniedRule("\\w.*\\.exe$");
 	pathManager.addAcceptedRule("^\\d");
 	if(pathMananager.isAllow("c:/temp/12.exe"))
 		System.out.println("accepted");
 	else
 		System.out.println("denied");
 }

package softwareskill;  
 
import java.util.HashSet;
 
/**
 *
 * @author mLri
 */
public class PathManager {
 
//field
    HashSet deniedRule;
    HashSet acceptedRule;
 
public static void main(String[] args) {
        PathManager pathManager = new PathManager();
        pathManager.addDeniedRule("\\w*\\.exe$");
        pathManager.addDeniedRule("\\w*\\.bat$");
        pathManager.addDeniedRule("\\w*\\.msi$");
        pathManager.addAcceptedRule("^\\d.*");
        pathManager.addAcceptedRule("\\w*(\\.jpg||\\.pdf||\\.png)$");
        //pathManager.addAcceptedRule("\\w*\\.png$");
        //pathManager.addAcceptedRule("\\w*\\.pdf$");
        if (pathManager.isAllow("c:/tem/2aaa.jpg")) {
            System.out.println("accepted");
        } else {
            System.out.println("denied");
        }
    }
 
public PathManager() {
        this.deniedRule = new HashSet();
        this.acceptedRule = new HashSet();
    }
 
public boolean addDeniedRule(String exp) {
        return this.deniedRule.add(exp);
    }
 
public boolean addAcceptedRule(String exp) {
        return this.acceptedRule.add(exp);
    }
 
public boolean isAllow(String file) {
        String[] tmp = file.split("/");
        if (tmp != null) {
            file = tmp[tmp.length-1];
        }
        if (this.checkDeniedRule(file)) {
            return this.checkAcceptRule(file);
        } else {
            return false;
        }
    }
 
private boolean checkAcceptRule(String file) {
        if (acceptedRule.isEmpty()) {
            return true;
        } else {
            for (String rule : acceptedRule) {
                //System.out.println("file is " + file);
                //System.out.println("rule is " + rule);
                if (file.matches(rule)) {
                    //System.out.println("rule is accepted");
                    return true;
                }
            }
            return false;
        }
    }
 
private boolean checkDeniedRule(String file) {
        if (deniedRule.isEmpty()) {
            return true;
        } else {
            for (String rule : deniedRule) {
                //System.out.println("file is " + file);
                //System.out.println("rule is " + rule);
                if (file.matches(rule)) {
                    //System.out.println("rule is denied");
                    return false;
                }
            }
            return true;
        }
    }
}