JAVA : How to get the positions of all matches in a String?
- by user692704
I have a text document and a query (the query could be more than one word). I want to find the position of all occurrences of the query in the document.
I thought of the documentText.indexOf(query) and using regular expression but I could not make it work.
I end up with the following method:
First, I have create a dataType called QueryOccurrence
public class QueryOccurrence implements Serializable{
public QueryOccurrence(){}
private int start;
private int end;
public QueryOccurrence(int nameStart,int nameEnd,String nameText){
start=nameStart;
end=nameEnd;
}
public int getStart(){
return start;
}
public int getEnd(){
return end;
}
public void SetStart(int i){
start=i;
}
public void SetEnd(int i){
end=i;
}
}
Then, I have used this datatype in the following method:
public static List<QueryOccurrence>FindQueryPositions(String documentText, String query){
// Normalize do the following: lower case, trim, and remove punctuation
String normalizedQuery = Normalize.Normalize(query);
String normalizedDocument = Normalize.Normalize(documentText);
String[] documentWords = normalizedDocument.split(" ");;
String[] queryArray = normalizedQuery.split(" ");
List<QueryOccurrence> foundQueries = new ArrayList();
QueryOccurrence foundQuery = new QueryOccurrence();
int index = 0;
for (String word : documentWords) {
if (word.equals(queryArray[0])){
foundQuery.SetStart(index);
}
if (word.equals(queryArray[queryArray.length-1])){
foundQuery.SetEnd(index);
if((foundQuery.End()-foundQuery.Start())+1==queryArray.length){
//add the found query to the list
foundQueries.add(foundQuery);
//flush the foundQuery variable to use it again
foundQuery= new QueryOccurrence();
}
}
index++;
}
return foundQueries;
}
This method return a list of all occurrence of the query in the document each one with its position.
Could you suggest any easer and faster way to accomplish this task.
Thanks
