edu.ucla.sspace.util.LineReader Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of sspace-wordsi Show documentation

The S-Space Package is a collection of algorithms for building Semantic Spaces as well as a highly-scalable library for designing new distributional semantics algorithms. Distributional algorithms process text corpora and represent the semantic for words as high dimensional feature vectors. This package also includes matrices, vectors, and numerous clustering algorithms. These approaches are known by many names, such as word spaces, semantic spaces, or distributed semantics and rest upon the Distributional Hypothesis: words that appear in similar contexts have similar meanings.

The newest version!

/*
 * Copyright 2011 David Jurgens
 *
 * This file is part of the S-Space package and is covered under the terms and
 * conditions therein.
 *
 * The S-Space package is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation and distributed hereunder to you.
 *
 * THIS SOFTWARE IS PROVIDED "AS IS" AND NO REPRESENTATIONS OR WARRANTIES,
 * EXPRESS OR IMPLIED ARE MADE.  BY WAY OF EXAMPLE, BUT NOT LIMITATION, WE MAKE
 * NO REPRESENTATIONS OR WARRANTIES OF MERCHANT- ABILITY OR FITNESS FOR ANY
 * PARTICULAR PURPOSE OR THAT THE USE OF THE LICENSED SOFTWARE OR DOCUMENTATION
 * WILL NOT INFRINGE ANY THIRD PARTY PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER
 * RIGHTS.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see .
 */

package edu.ucla.sspace.util;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOError;
import java.io.IOException;

import java.util.Iterator;
import java.util.NoSuchElementException;


/** 
 * A utility class for reading the lines of a file.  This class is specifically
 * designed to support replacing the code
 * *try {
 *    BufferedReader br = new BufferedReader(new FileReader(file));
 *    for (String line = null; (line = br.readLine()) != null; ) {
 *        // work
 *    }
 *} catch (IOException ioe) {
 *    // handling code
 *} finally {
 *    br.close();
 *}
 *
 *
 * with the code
 *
 * *for (String line : new LineReader(file) {
 *    // work
 *}
 *
 *
 * This class with automatically close the stream up on finishing or upon error.
 * All {@link IOException} instances are rethrown as {@link IOError}.
 *
 * @author David Jurgens
 */
public class LineReader implements Iterable {

    /**
     * The backing file
     */
    private final File f;

    /**
     * Creates a line reader for the provided file.
     */
    public LineReader(File f) {
        this.f = f;
    }
    
    /**
     * Returns an iterator over the lines in the file.
     */
    public Iterator iterator() {
        return new LineIterator();
    }

    /**
     * The backing iterator class that does the actual line reading from the
     * file.
     */
    private class LineIterator implements Iterator {
        
        /**
         * The reader for the file.
         */
        private final BufferedReader br;

        /**
         * The next line to return.
         */
        private String next;

        public LineIterator() {
            try {
                br = new BufferedReader(new FileReader(f));
                advance();
            } catch (IOException ioe) {
                throw new IOError(ioe);
            }
        }

        private void advance() {
            try {
                next = br.readLine();
                // Close the reader if no further lines exist.
                if (next == null)
                    br.close();
            }
            catch (IOException ioe) {
                throw new IOError(ioe);
            }
        }

        public boolean hasNext() {
            return next != null;
        }

        public String next() {
            if (next == null)
                throw new NoSuchElementException();
            String n = next;
            advance();
            return n;
        }

        public void remove() {
            throw new UnsupportedOperationException(
                "Cannot remove line from file");
        }
    }
}