Programming Problem 15.14 IdentifierIndex with LabRat

Write a program that reads a Java source file and produces an index of all identifiers in the file. For each identifier, print all lines in which it occurs.

Hint: Call in.useDelimiter("[^A-Za-z0-9_]+"). Then each call to next returns a string consisting only of letters, numbers, and underscores.

Use the following class as your main class:

import java.io.FileNotFoundException; import java.util.Set; /** A program to read in a Java source file and produce an index of all identifiers in the file. */ public class IndexDemo { public static void main(String[] args) throws FileNotFoundException { IdentifierIndex index = new IdentifierIndex(); index.read("IndexDemo.java"); // reads this file Set idents = index.getIdentifiers(); for (String ident : idents) { Set lines = index.getLines(ident); System.out.println(ident + ": " + lines); } } } 

Complete the following class in your solution:

/** A class to read in a Java source file and produce an index of all identifiers in the file. */ . . . public class IdentifierIndex { . . . /** Reads all identifiers from the given file @param filename the file name */ public void read(String filename) throws FileNotFoundException { . . . } /** A set of all identifiers that occur in the file, in sorted order. */ public Set getIdentifiers() { . . . } /** Gets all line numbers on which the given identifier occurs. @param identifier an identifier @return all line numbers on which the identifier was found, in increasing order; an empty set (not null) if the identifier was never found */ public Set getLines(String identifier) { . . . } } 

Use the following class as your tester class:

import java.io.FileNotFoundException; import java.util.Iterator; import java.util.Set; public class IndexTester { public static void main(String[] args) throws FileNotFoundException { IdentifierIndex index = new IdentifierIndex(); index.read("IndexTester.java"); // reads this file Set idents = index.getIdentifiers(); String last = ""; for (String s : idents) { last = s; } System.out.println(last); // The last identifier System.out.println("Expected: void"); Set lines = index.getLines("void"); System.out.println(lines); System.out.println("Expected: [7, 16, 17]"); System.out.println(index.getLines("f" + "oo")); System.out.println("Expected: []"); } }