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Handful shortcuts for Java programming, Java 7 compatible.
/*******************************************************************************
* Copyright (C) 2009, 2015, Danilo Pianini and contributors
* listed in the project's build.gradle or pom.xml file.
*
* This file is distributed under the terms of the Apache License, version 2.0
*******************************************************************************/
package org.danilopianini.io;
import java.awt.Image;
import java.awt.Toolkit;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.net.URL;
import java.nio.charset.Charset;
import java.util.zip.CRC32;
import org.apache.commons.io.FileUtils;
import com.google.common.base.Charsets;
/**
* This is a collection of tools for manipulating the file system.
*
* @author Danilo Pianini
* @version 20111021
*
*/
public final class FileUtilities {
private static final String BACKUP_EXTENSION = ".bak";
/**
* This method provides a shortcut to deep clone Serializable objects.
*
* @param x
* the object to clone
* @return a deep clone of x
* @param
* the Object type
* @throws IOException
* If your memory fails
* @throws ClassNotFoundException
* it never should
*/
@SuppressWarnings("unchecked")
public static T cloneObject(final T x) throws IOException, ClassNotFoundException {
final ByteArrayOutputStream bout = new ByteArrayOutputStream();
final ObjectOutputStream cout = new ObjectOutputStream(bout);
cout.writeObject(x);
final ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
final ObjectInputStream cin = new ObjectInputStream(bin);
return (T) cin.readObject();
}
/**
* Serializes an object in memory. Its representation as byte[] is returned
*
* @param b
* the byte array representation of object to serialize
* @return The Object
* @param
* the Object type
*/
@SuppressWarnings("unchecked")
public static T deserializeObject(final byte[] b) {
try {
final ByteArrayInputStream bin = new ByteArrayInputStream(b);
final ObjectInputStream cin = new ObjectInputStream(bin);
return (T) cin.readObject();
} catch (ClassNotFoundException | IOException e) {
e.printStackTrace(); // NOPMD by danysk on 8/20/13 1:48 PM
}
return null;
}
/**
* Computes the CRC32 sum for a given file.
*
* @param f
* the file
* @return the CRC32
* @throws IOException
* if an I/O error occurs
*/
public static long fileCRC32sum(final File f) throws IOException {
try (final InputStream is = new FileInputStream(f)) {
final CRC32 crc = new CRC32();
int val;
do {
val = is.read();
crc.update(val);
} while (val != -1);
is.close();
return crc.getValue();
}
}
/**
* This method tries to resemble an Object from a file.
*
* @param f
* the file to load
* @return the loaded Object (already cast to Serializable)
* @throws IOException
* in case of I/O errors
* @throws ClassNotFoundException
* in case there is no compatible Class in Classpath for the
* Object to be loaded
*/
public static Serializable fileToObject(final File f) throws IOException, ClassNotFoundException {
if (f.exists()) {
try (final ObjectInputStream ois = new ObjectInputStream(new FileInputStream(f))) {
final Serializable res = (Serializable) ois.readObject();
ois.close();
return res;
}
}
return null;
}
/**
* This method tries to resemble an Object from a file.
*
* @param path
* the path of the file to load
* @return the loaded Object (already cast to Serializable)
* @throws IOException
* in case of I/O errors
* @throws ClassNotFoundException
* in case there is no compatible Class in Classpath for the
* Object to be loaded
*/
public static Object fileToObject(final String path) throws IOException, ClassNotFoundException {
return fileToObject(new File(path));
}
/**
* This method tries to read a file and to instance it as a String.
*
* @param f
* the file to read
* @return the file as String
* @throws IOException
* in case of I/O errors
* @deprecated Developers should use
* {@link FileUtils#readFileToString(File, String)} from Apache
* Commons IO
*/
@Deprecated
public static String fileToString(final File f) throws IOException {
return FileUtils.readFileToString(f, Charsets.UTF_8.name());
}
/**
* This method tries to read a file and to instance it as a String.
*
* @param path
* the path of the file to read
* @return the file as String
* @throws IOException
* in case of I/O errors
* @deprecated Use {@link FileUtilities#fileUTF8ToString(String)} instead, or specify a {@link Charset}.
*/
@Deprecated
public static String fileToString(final String path) throws IOException {
return fileToString(new File(path));
}
/**
* This method tries to read a file and to instance it as a String.
*
* @param path
* the path of the file to read
* @return the file as String
* @throws IOException
* in case of I/O errors
*/
public static String fileUTF8ToString(final String path) throws IOException {
return fileToString(path, Charsets.UTF_8);
}
/**
* This method tries to read a file and to instance it as a String.
*
* @param path
* the path of the file to read
* @param c
* the {@link Charset} to use
* @return the file as String
* @throws IOException
* in case of I/O errors
*/
public static String fileToString(final String path, final Charset c) throws IOException {
return FileUtils.readFileToString(new File(path), c.name());
}
/**
* Tests whether or not any parent of the given file is hidden.
*
* @param file
* the file to test
* @return true if at least one of the parent directories is hidden
*/
public static boolean isInHiddenPath(final File file) {
boolean hidden = false;
File f = file;
do {
hidden = f.isHidden();
f = f.getParentFile();
} while (!(hidden || f == null));
return hidden;
}
/**
* This method loads an Image from the file system.
*
* @param path
* the path of the file to read
* @return the loaded image
*/
public static Image loadImage(final String path) {
final ClassLoader loader = ClassLoader.getSystemClassLoader();
final URL fileLocation = loader.getResource(path);
final Image img = Toolkit.getDefaultToolkit().getImage(fileLocation);
if (img != null) {
return img;
}
return Toolkit.getDefaultToolkit().getImage(fileLocation);
}
/**
* This method serializes an Object into a File.
*
* @param s
* the Object to serialize
* @param f
* the File which will contain the serialized Object
* @param backup
* If true and the file already exists, the ".bak" extension will
* be added to the existing file, preventing overwriting
* @throws IOException
* in case of I/O errors
*/
public static void objectToFile(final Object s, final File f, final boolean backup) throws IOException {
final String op = f.getAbsolutePath();
if (backup && f.exists() && !f.renameTo(new File(op + BACKUP_EXTENSION))) {
throw new IOException("Can not move " + op + " to " + op + BACKUP_EXTENSION);
}
final File ef = new File(op);
try (final ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(ef))) {
oos.writeObject(s);
oos.close();
}
}
/**
* This method serializes an Object into a File.
*
* @param s
* the Object to serialize
* @param path
* the path of the File which will contain the serialized Object
* @param backup
* If true and the file already exists, the ".bak" extension will
* be added to the existing file, preventing overwriting
* @throws IOException
* in case of I/O errors
*/
public static void objectToFile(final Serializable s, final String path, final boolean backup) throws IOException {
objectToFile(s, new File(path), backup);
}
/**
* Serializes an object in memory. Its representation as byte[] is returned
*
* @param x
* the object to serialize
* @return its byte array representation
* @param
* the Object type
*/
public static byte[] serializeObject(final T x) {
try {
final ByteArrayOutputStream bout = new ByteArrayOutputStream();
final ObjectOutputStream cout = new ObjectOutputStream(bout);
cout.writeObject(x);
return bout.toByteArray();
} catch (IOException e) {
e.printStackTrace(); // NOPMD by danysk on 8/20/13 1:48 PM
}
return new byte[0];
}
/**
* This method takes a String and save it as a Text file.
*
* @param s
* the String to save
* @param f
* the File to write to
* @param append
* decides whether to append or overwrite the file
* @throws IOException
* in case of I/O errors
* @deprecated use {@link FileUtils#writeStringToFile(File, String, Charset)} instead
*/
@Deprecated
public static void stringToFile(final String s, final File f, final boolean append) throws IOException {
final String op = f.getAbsolutePath();
if (f.exists() && !f.renameTo(new File(op + BACKUP_EXTENSION))) {
throw new IOException("Can not move " + op + " to " + op + BACKUP_EXTENSION);
}
FileUtils.writeStringToFile(f, s);
}
/**
* This method takes a String and save it as a Text file. This method
* overwrites.
*
* @param string
* the String to save
* @param path
* the path of the File to write to
* @throws IOException
* in case of I/O errors
* @deprecated use {@link FileUtils#writeStringToFile(File, String, Charset)} instead
*/
public static void stringToFile(final String string, final String path) throws IOException {
stringToFile(string, path, false);
}
/**
* /** This method takes a String and save it as a Text file.
*
* @param string
* the String to save
* @param path
* the File to write to
* @param append
* decides whether to append or overwrite the file
* @throws IOException
* in case of I/O errors
* @deprecated use {@link FileUtils#writeStringToFile(File, String, Charset, boolean)} instead
*/
public static void stringToFile(final String string, final String path, final boolean append) throws IOException {
stringToFile(string, new File(path), append);
}
private FileUtilities() {
}
}
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