abstractngram.java

Boosting算法软件包

package jboost.examples.ngram;

import java.util.Enumeration;
import java.util.NoSuchElementException;
import java.util.StringTokenizer;

/**
 * This is the abstract class for all ngrams.  The constructor and
 * nextElement methods (used for all ngrams) are defined.
 *
 * @author Rob Schapire (rewritten by Aaron Arvey)
 */

abstract class AbstractNgram implements Enumeration {

    /** The stream of ngrams */
    Enumeration enumer;   

    /** The words in the original string */  
    String[] words;       

    /**
     * The constructor simply sets up the array of words.
     */
    AbstractNgram(String s) {
	StringTokenizer st = new StringTokenizer(s);
	words = new String[st.countTokens()];
	int i = 0;
	while(st.hasMoreElements()) {
	    words[i] = st.nextToken();
	    i += 1;
	}
    }

    /**
     * @return true if there are more elements
     */
    abstract public boolean hasMoreElements();

    /**
     * @return next element
     */
    public Object nextElement() {
	if (!hasMoreElements())
	    throw new NoSuchElementException();
	return ((String) enumer.nextElement());
    }

    /** a main for testing 
    public static void main(String[] argv) {
	int size = Integer.parseInt(argv[0]);
	String ngram_type = argv[1];
	java.io.BufferedReader in = new java.io.BufferedReader(new
	    java.io.InputStreamReader(System.in));
	String line;
	try {
	    while ((line = in.readLine()) != null) {
		Enumeration st;
		if (ngram_type.equals("sparse"))
		    st = new SparseNgram(line, size);
		else if (ngram_type.equals("full"))
		    st = new FullNgram(line, size);
		else // fixed ngram
		    st = new FixedNgram(line, size);
		while(st.hasMoreElements()) {
		    System.out.println((String) st.nextElement());
		}
	    }
	}
	catch (java.io.IOException e) {
	    e.printStackTrace();
	}
    }
    */
}