在动态字符串中形成正确的正则表达式

Question

I have a FileInputStream who reads a file which somewhere contains a string subset looking like:

...
    OperatorSpecific(XXX)
    {
       Customer(someContent)
       SaveImage()
       {
...

I would like to identify the Customer(someContent) part of the string and switch the someContent inside the parenthesis for something else.

someContent will be a dynamic parameter and will contain a string of maybe 5-10 chars.

I have used regEx before, like once or twice, but I feel that in a context such as this where I don't know what value will be inside the parenthesis I'm at a loss of how I should express it...

In summary I want to have a string returned to me which has my someContent value inside the Customer-parenthesis.

Does anyone have any bright ideas of how to get this done?

Answer 1

Try this one (double the escaping backslashes for the use in java!)

(?<=Customer\()[^\)]*

And replace with your content.

See it here at Regexr

(?<=Customer\\() is look behind assertion. It checks at every position if there is a "Customer(" on the left, if yes it matches on the right all characters that are not a ")" with the [^\\)]* , this is then the part that will be replaced.

Some working java code

Pattern p = Pattern.compile("(?<=Customer\\()[^\\)]*");
String original = "Customer(someContent)";
String Replacement = "NewContent";

Matcher m = p.matcher(original);
String result = m.replaceAll(Replacement);

System.out.println(result);

This will print

Customer(NewContent)

Answer 2

Untested, but something like the following should work:

Pattern pattern = Pattern.compile("\\s+Customer\\(\\s*(\\w+)\\s*\\)\\s*");
Matcher matcher = pattern.matcher(input);
matcher.matches();

System.out.println(matcher.group(1));

EDIT

This of course won't work with all possible cases:

// legal variable names
Customer(_someContent)
Customer($some_Content)

Answer 3

Using groups works and non-greedy works:

String s = 
    "OperatorSpecific(XXX)\n    {\n" +
    "       Customer(someContent)\n" +
    "       SaveImage()       {";
Pattern p = Pattern.compile("Customer\\((.*?)\\)");
Matcher matcher = p.matcher(s);
if (matcher.find()) {
    System.out.println(matcher.group(1));
}

will print

someContent