/starter/src/cs276/pe1/spell/SpellingScorer.java

package cs276.pe1.spell;

import java.io.File;
import java.util.Arrays;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import cs276.util.IOUtils;

/**
 * Scorer for evaluating a SpellingCorrector.  Reads a file
 * that contains correctly spelled words and, for each, one or
 * more mis-spellings.  A SpellingCorrector class is then
 * instantiated (the specific type is passed as an argument
 * and it is assumed to have a no-arg constructor).
 * 
 * @author dramage
 */
public class SpellingScorer {

	/**
	 * Prints usage information, a status message, and an optional exit 
	 * reason before exiting with status -1.
	 */
	public static void usage(String message, Throwable cause) {
		System.err.println("CS276 PE1 Scoring Script");
		System.err.println();
		System.err.println("Usage: ");
		System.err.println("  (java-cmd) SpellingScorer cs276.pe1.spell.YourSpellingCorrectorClass");
		System.err.println();
		System.err.println(message);
		if (cause != null) {
			cause.printStackTrace();
		}
		System.exit(-1);
	}
	
	/**
	 * Default usage information with no extra reasons provided.
	 */
	public static void usage() {
		usage("",null);
	}
	
	public static void main(String[] argv) {
		if (argv.length < 1 || argv.length > 2) {
			usage();
		}
		
		// instantiate scorer
		SpellingCorrector scorer = null;
		try {
			Class<?> type = Class.forName(argv[0]);
			scorer = (SpellingCorrector)type.newInstance();
		} catch (Exception e) {
			usage("Error while instantiating corrector " + argv[0]
					+ ": does it have a public no-args constructor?", e);
		}
		
		// load words file
		File wordsFile = new File(argv.length == 2 ? argv[1]
				: "/afs/ir/class/cs276/pe1-2011/spelltest.txt");
		if (!wordsFile.exists() || !wordsFile.canRead()) {
			usage();
		}
		Map<String,List<String>> words = new LinkedHashMap<String,List<String>>();
		try {
			for (String line : IOUtils.readLines(IOUtils.openFile(wordsFile))) {
				List<String> split = Arrays.asList(line.split("\\s+"));
				words.put(split.get(0), split.subList(1, split.size()));
				}
		} catch (Exception e) {
			usage("Error while loading words file from " + wordsFile, e);
		}
		
		// score words
		final long startTime = System.currentTimeMillis();
		int nCorrect = 0;
		int nTotal = 0;
		for (Map.Entry<String, List<String>> entry : words.entrySet()) {
			final String word = entry.getKey();
			for (String misspelling : entry.getValue()) {
				List<String> corrections = scorer.corrections(misspelling);
				if (!corrections.isEmpty() && corrections.get(0).equals(word)) {
					nCorrect += 1;
				}
				nTotal += 1;
			}
		}
		
		System.out.println(argv[0] + ": " + nCorrect + "/" + nTotal + " in "
				+ (System.currentTimeMillis() - startTime + "ms"));
	}
	
}