MVEL extracting a string from a string - mvel

Question

I have the strings "000134567 - AA - 2001" and "002134567 - AB - 2001" and I want to extract all the numbers before the " - AA". But I only want to return the numbers starting from the first non-zero number. For example, I would want "134567" or "2134567".
Is there some function that would allow me to do this using MVEL? Any help is appreciated.

Answer 1

I do not think directly we can use MVEL for this, but yes tweaking little bit might help us.
import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;
import org.mvel2.MVEL;
import org.mvel2.ParserContext;
import org.mvel2.integration.VariableResolverFactory;
import org.mvel2.integration.impl.MapVariableResolverFactory;
public class MyTest {
public static void main(String[] args) {
String myString = "000134567 - AA - 2001";
Map contextMap = new HashMap();
contextMap.put("myString", myString);
ParserContext ctx = new ParserContext();
ctx.addPackageImport("java.util.regex");
Serializable s = MVEL.compileExpression("outputString(myString)", ctx);
System.out.println(MVEL.executeExpression(s, contextMap, getMvelFactory(contextMap)));
}
private static VariableResolverFactory getMvelFactory(Map contextMap) {
VariableResolverFactory functionFactory = new MapVariableResolverFactory(contextMap);
MVEL.eval(
"outputString = def (myString) { java.util.regex.Pattern p = java.util.regex.Pattern.compile(\"[0-9]+\"); java.util.regex.Matcher m = p.matcher(myString); if (m.find()) { String output = m.group(); return output.replaceAll(\"^0+\", \"\");}};",
functionFactory);
return functionFactory;
}
}
Function
Below is my function written in java which i have included inside Mvel VariableResolverFactory.
outputString = def (myString) {
java.util.regex.Pattern p = java.util.regex.Pattern.compile("[0-9]+");
Matcher m = p.matcher(myString);
if (m.find()) {
String output = m.group();
return output.replaceAll("^0+", "");
}
};
Creating Parser Context and adding import
Since java.util.regex package is not available with MVEL, so we will import this package explicitly.
ParserContext ctx = new ParserContext();
ctx.addPackageImport("java.util.regex");
Compiling Expression using above Import
This will just compile the expression and will add imports for later use while evaluation.
Serializable s = MVEL.compileExpression("outputString(myString)", ctx);
Varying variable
You can pass through your variables as below,
Map contextMap = new HashMap();
contextMap.put("myString", myString);
Rest you can change the function body, signature and return statement as per your needs.