edu.berkeley.nlp.util.ObjectReader Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of berkeleyparser Show documentation

The Berkeley parser analyzes the grammatical structure of natural language using probabilistic context-free grammars (PCFGs).

The newest version!

/**
 * 
 */
package edu.berkeley.nlp.util;

import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.util.Arrays;

import edu.berkeley.nlp.util.Logger;

/**
 * @author dburkett
 *
 */
public class ObjectReader {
	private final File folder;
	private final String[] files;
	
	private ObjectInputStream currentStream = null;
	private int currentIndex = -1;
	private boolean currentStreamHasNext = false;
	
	public ObjectReader(File folder, final String filenameFilter) {
		this.folder = folder;
		files = folder.list(new FilenameFilter() {
			public boolean accept(File dir, String name) {
				return name.contains(filenameFilter);
			}
		});
		Arrays.sort(files);
		openNextStream();
	}
	
	public void reset() {
		currentIndex = -1;
		openNextStream();
	}

	private void openNextStream() {
		try {
			if (currentStream != null) {
				currentStream.close();
				currentStream = null;
			}
			currentIndex++;
			if (currentIndex < files.length) {
				currentStream = IOUtils.openObjIn(new File(folder, files[currentIndex]));
				currentStreamHasNext = currentStream.readBoolean();
			}
		} catch(IOException e) {
			Logger.err("Error opening forest file: " + e);
			currentStream = null;
		}
	}

	@SuppressWarnings("unchecked")
	public T getNextObject() {
		try {
			while (!currentStreamHasNext && currentStream != null) {
				openNextStream();
			}
			if (currentStream == null) {
				return null;
			}
			T nextObject = (T)currentStream.readObject();
			currentStreamHasNext = currentStream.readBoolean();
			return nextObject;
		} catch(Exception e) {
			Logger.err("Error reading object: " + e);
			return null;
		}
	}

}