Parse through string for known section

Question

I was wondering what the best way to go about parsing "HOST" names out of oracle connection strings. Here is an example connection string:

Data Source=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=MyHost)(PORT=MyPort)))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=MyOracleSID)))

And I have it in a String. What is the best way to get "MyHost" returned. Also would be nice if it worked for double connection strings, example:

((Data Source=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=MyHost1)(PORT=MyPort1)))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=MyOracleSID1))))(Data Source=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=MyHost2)(PORT=MyPort2)))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=MyOracleSID2)))))

Would return "MyHost1" and "MyHost2".

Trying to write a method that takes in a connection string and spits out the host/hosts in an array list of strings.

Answer 1

Using a regular expression like this should work: \(HOST=([^)]+)\).

Don't forget to double the backslashes in Java String literals:

Pattern hostPattern = Pattern.compile("\\(HOST=([^)]+)\\)");

Create a Matcher from that Patttern and your input string using matcher() and call find() until it returns false. Use group(1) to get the host names:

Matcher m = hostPattern.matcher(input);
while (m.find()) {
  System.out.println(m.group(1));
}

Answer 2

Extending Joachim's idea (and I haven't used ArrayLists in a while so it may not be totally correct):

public List<String> getHosts(String conString) {
  List<String> conns = new ArrayList<String>()
  Pattern hostPattern = Pattern.compile("\\(HOST=([^)]+)\\)");
  Matcher m = hostPattern.matcher(conString);
  while(m.find()) {
    conns.add(m.group(1));
  }
  return conns;
}

EDIT: Thanks for the fixes Bart!

Answer 3

The regular expression \(HOST=(.*?)\) will match the section "(HOST=MyHost1)" and "(HOST=MyHost2)" as two groups containing "MyHost1" and "MyHost2" respectively.

Cheers,

Ed