// Example 142 from page 113

//

import java.util.*;

import java.io.*;

// A concordance is a TreeMap mapping a word (a String) to a TreeSet

// of linenumbers (Integer objects)

class Example142 {

public static void main(String[] args) throws IOException {

if (args.length != 1)

System.out.println("Usage: java Example142 <filename>");

else {

SortedMap<String,SortedSet<Integer>> index = buildIndex(args[0]);

printIndex(index);

}

}

// Parse alphanumeric words from the given file, and record them in

// the index. The resulting index is a SortedMap from String to

// SortedSet of Integer (the line numbers).

static SortedMap<String,SortedSet<Integer>> buildIndex(String filename)

throws IOException

{

Reader r = new BufferedReader(new FileReader(filename));

StreamTokenizer stok = new StreamTokenizer(r);

stok.quoteChar('"'); stok.ordinaryChars('!', '/');

stok.nextToken();

SortedMap<String,SortedSet<Integer>> index

= new TreeMap<String,SortedSet<Integer>>();

// = new TreeMap<String,SortedSet<Integer>>(new IgnoreCaseComparator());

while (stok.ttype != StreamTokenizer.TT_EOF) {

if (stok.ttype == StreamTokenizer.TT_WORD) {

SortedSet<Integer> ts;

if (index.containsKey(stok.sval)) // If word has a set, get it

ts = index.get(stok.sval);

else {

ts = new TreeSet<Integer>(); // Otherwise create one

index.put(stok.sval, ts);

}

ts.add(stok.lineno());

}

stok.nextToken();

}

return index;

}

// Print the concordance index by iterating over its entries, and

// for each entry, iterate over the value which is a set.

static void printIndex(SortedMap<String,SortedSet<Integer>> index) {

for (Map.Entry<String,SortedSet<Integer>> entry : index.entrySet()) {

System.out.print(entry.getKey() + ": ");

SortedSet<Integer> lineNoSet = entry.getValue();

for (int lineno : lineNoSet)

System.out.print(lineno + " ");

System.out.println();

}

}

}