/* Copyright (C) 2003 Univ. of Massachusetts Amherst, Computer Science Dept.
This file is part of "MALLET" (MAchine Learning for LanguagE Toolkit).
http://www.cs.umass.edu/~mccallum/mallet
This software is provided under the terms of the Common Public License,
version 1.0, as published by http://www.opensource.org. For further
information, see the file `LICENSE' included with this distribution. */
package cc.mallet.util;
import java.io.*;
import java.util.ArrayList;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;
/**
* Contains static utilities for manipulating files.
*
* Created: Thu Nov 20 15:14:16 2003
*
* @author <a href="mailto:casutton@cs.umass.edu">Charles Sutton</a>
* @version $Id: FileUtils.java,v 1.1 2007/10/22 21:37:40 mccallum Exp $
*/
public class FileUtils {
private FileUtils() {} // All static methods
/**
* Serializes an object to a file, masking out annoying exceptions.
* Any IO exceptions are caught, and printed to standard error.
* Consider using {@link #writeGzippedObject(java.io.File, java.io.Serializable)}
* instead, for that method will compress the serialized file, and it'll still
* be reaoable by {@link #readObject}.
* @param f File to write to
* @param obj Object to serialize
* @see #writeGzippedObject(java.io.File, java.io.Serializable)
*/
public static void writeObject (File f, Serializable obj)
{
try {
ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(f));
oos.writeObject(obj);
oos.close();
}
catch (IOException e) {
System.err.println("Exception writing file " + f + ": " + e);
}
}
/**
* Reads a Serialized object, which may or may not be zipped.
* Guesses from the file name whether to decompress or not.
* @param f File to read data from
* @return A deserialized object.
*/
public static Object readObject (File f)
{
String fname = f.getName ();
if (fname.endsWith (".gz")) {
return readGzippedObject (f);
} else {
return readUnzippedObject (f);
}
}
/**
* Reads a serialized object from a file.
* You probably want to use {@link #readObject} instead, because that method will automatically guess
* from the extension whether the file is compressed, and call this method if necessary.
* @param f File to read object from
* @see #readObject
*/
public static Object readUnzippedObject (File f)
{
try {
ObjectInputStream ois = new ObjectInputStream(new FileInputStream(f));
Object obj = ois.readObject();
ois.close ();
return obj;
}
catch (IOException e) {
throw new RuntimeException (e);
} catch (ClassNotFoundException e) {
throw new RuntimeException (e);
}
}
/**
* Reads every line from a given text file.
* @param f Input file.
* @return String[] Array containing each line in <code>f</code>.
*/
public static String[] readFile (File f) throws IOException
{
BufferedReader in = new BufferedReader(new FileReader (f));
ArrayList list = new ArrayList ();
String line;
while ((line = in.readLine()) != null)
list.add (line);
return (String[]) list.toArray(new String[0]);
}
/**
* Creates a file, making sure that its name is unique.
* The file will be created as if by <tt>new File(dir, prefix+i+extension)</tt>,
* where i is an integer chosen such that the returned File does not exist.
* @param dir Directory to use for the returned file
* @param prefix Prefix of the file name (before the uniquifying integer)
* @param extension Suffix of the file name (after the uniquifying integer)
*/
public static File uniqueFile (File dir, String prefix, String extension)
throws IOException
{
File f = null;
int i = 0;
boolean wasCreated = false;
while (!wasCreated) {
if (dir != null) {
f = new File (dir, prefix+i+extension);
} else {
f = new File (prefix+i+extension);
}
wasCreated = f.createNewFile ();
i++;
}
return f;
}
/**
* Writes a serialized version of obj to a given file, compressing it using gzip.
* @param f File to write to
* @param obj Object to serialize
*/
public static void writeGzippedObject (File f, Serializable obj)
{
try {
ObjectOutputStream oos = new ObjectOutputStream (new BufferedOutputStream (new GZIPOutputStream (new FileOutputStream(f))));
oos.writeObject(obj);
oos.close();
}
catch (IOException e) {
System.err.println("Exception writing file " + f + ": " + e);
}
}
/**
* Reads a serialized object from a file that has been compressed using gzip.
* You probably want to use {@link #readObject} instead, because it will automatically guess
* from the extension whether the file is compressed, and call this method if necessary.
* @param f Compressed file to read object from
* @see #readObject
*/
public static Object readGzippedObject (File f)
{
try {
ObjectInputStream ois = new ObjectInputStream (new BufferedInputStream (new GZIPInputStream (new FileInputStream(f))));
Object obj = ois.readObject();
ois.close ();
return obj;
}
catch (IOException e) {
throw new RuntimeException (e);
} catch (ClassNotFoundException e) {
throw new RuntimeException (e);
}
}
} // FileUtils