Most efficient data structure for searching for a word in text Java

Question

I have a program which reads in a document and searches each page for a given search word. It then returns which pages the word appears in.

i.e. the word "brilliant" appears in the following pages: 1,4,6,8

At the moment I split the file into pages and store this into an ArrayList. Each element of the ArrayList contains one page of the document

I then split each word on the page and store it into a hashMap, with the KEY being the position in the text this word appears in (i need to know this for other functionality) and the value being the word. I then search through the HashMap using;

if (map.containsValue(searchString) == true)
                return true;
             else
                 return false;

I do this for each PAGE.

Everything is working but I was wondering if there is a more efficient data structure I can use which stores all the words on a given page as well as the position on the page it appears?(since searching through the values in a map without giving a key is 0(n)).

I need to be able to search through this structure and find a word. Remember I also need the position for later use.

The code that i use to populate the map with the positions of the word in the text is;

    // text is the page of text from a document as a string
int key = 1; // position of the word in the text
    for (String element : text.split(" "))
            {
                map.put(key, element);
                key++;
            }

Answer 1

Why not just use a single HashMap<String,ArrayList<Position>> that maps the words to the occurrences? Each word of the text would be a key in the map, the page number and position would form the entry list.

Insertion is slightly tricky because of the list value:

ArrayList<Position> positions = words.get(word);
if (positions == null) {
  positions = new ArrayList<Position>();
  words.put(word, positions);
}
positions.add(position);

Alernatively, you could use a Guava Multimap: http://docs.guava-libraries.googlecode.com/git/javadoc/com/google/common/collect/Multimap.html (In particular if you are using Guava for other purposes already -- I'd probably avoid pulling in a library dependency just for this)

Edit: Changed Integer to Position (and the set to a list), had overlooked that the exact position is required. Position should be similar to

class Position {
  int page;
  int index; 
}