Phone Number custom validation using Regular Expression in ADF and Java

Regular Expression (REGEX) is the best method to validate phone number. emailId, name in Java.
Here I have written this validation code for phone number using Regular Expression and Java code to use this in an Oracle ADF Application.

public void phoneNoValidator(FacesContext facesContext, UIComponent uIComponent, Object object) {
        String msg2 = "";
        if (object != null) {
            String phnNo = object.toString();
            int openB = 0;
            int closeB = 0;
            boolean closeFg = false;
            char[] xx = phnNo.toCharArray();
            for (char c : xx) {
                if (c == '(') {
                    openB = openB + 1;
                } else if (c == ')') {
                    closeB = closeB + 1;
                }

                if (closeB > openB) {
                    closeFg = true; //closed brackets will not be more than open brackets at any given time.
                }
            }
            //if openB=0 then no. of closing and opening brackets equal || opening bracket must always come before closing brackets
            //closing brackets must not come before first occurrence of openning bracket
            if (openB != closeB || closeFg == true || (phnNo.lastIndexOf("(") > phnNo.lastIndexOf(")")) ||
                (phnNo.indexOf(")") < phnNo.indexOf("("))) {
                msg2 = "Brackets not closed properly.";
                FacesMessage message2 = new FacesMessage(msg2);
                message2.setSeverity(FacesMessage.SEVERITY_ERROR);
                throw new ValidatorException(message2);
            }
            if (phnNo.contains("()")) {
                msg2 = "Empty Brackets are not allowed.";
                FacesMessage message2 = new FacesMessage(msg2);
                message2.setSeverity(FacesMessage.SEVERITY_ERROR);
                throw new ValidatorException(message2);
            }
            if (phnNo.contains("(.") || phnNo.contains("(-") || phnNo.contains("-)")) {
                msg2 = "Invalid Phone Number.Check content inside brackets.";
                FacesMessage message2 = new FacesMessage(msg2);
                message2.setSeverity(FacesMessage.SEVERITY_ERROR);
                throw new ValidatorException(message2);
            }

            openB = 0;
            closeB = 0;
            closeFg = false;
            //check for valid language name.Allowed- brackets,dots,hyphen

            String expression = "([0-9\\-\\+\\(\\)]+)";
            CharSequence inputStr = phnNo;
            Pattern pattern = Pattern.compile(expression);
            Matcher matcher = pattern.matcher(inputStr);
            String error = "Invalid Phone Number";
            System.out.println("Index of plus is--->" + phnNo.lastIndexOf("+"));
            System.out.println("Bracket index--->" + phnNo.charAt(0));

            if (matcher.matches()) {
                if (phnNo.contains("++") || phnNo.contains("--")) {
                    throw new ValidatorException(new FacesMessage(FacesMessage.SEVERITY_ERROR, error,
                                                                  "Can not contain two hyphen(--) or plus(++)"));
                } else if (phnNo.lastIndexOf("+") > 1) {
                    throw new ValidatorException(new FacesMessage(FacesMessage.SEVERITY_ERROR, error,
                                                                  "Plus sign should be in proper place"));
                } else if (phnNo.lastIndexOf("+") == 1 && phnNo.charAt(0) != '(') {
                    throw new ValidatorException(new FacesMessage(FacesMessage.SEVERITY_ERROR, error,
                                                                  "Plus sign should be in proper place"));
                } else if (phnNo.startsWith(" ") || phnNo.endsWith(" ")) {
                    throw new ValidatorException(new FacesMessage(FacesMessage.SEVERITY_ERROR, error,
                                                                  "Space Not allowed at start and end"));
                }

            } else {
                throw new ValidatorException(new FacesMessage(FacesMessage.SEVERITY_ERROR, error,
                                                              "Only numeric character,+,() and - allowed"));
            }

        }
    }

Cheers:) Happy Learning