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Common, generally useful utilities
/* The contents of this file are subject to the license and copyright terms
* detailed in the license directory at the root of the source tree (also
* available online at http://fedora-commons.org/license/).
*/
package org.fcrepo.utilities;
import java.io.File;
import java.io.FileFilter;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Properties;
import java.util.Set;
public class FileUtils {
/**
* Copy an InputStream to an OutputStream.
* While this method will automatically close the destination OutputStream,
* the caller is responsible for closing the source InputStream.
*
* @param source
* @param destination
* @return true if the operation was successful;
* false otherwise (which includes a null input).
* @see http://java.sun.com/docs/books/performance/1st_edition/html/JPIOPerformance.fm.html#22980
*/
public static boolean copy(InputStream source, OutputStream destination) {
return copy(source, destination, new byte[4096]);
}
public static boolean copy(InputStream source, OutputStream destination, byte[] buffer) {
try {
int n = 0;
while (-1 != (n = source.read(buffer))) {
destination.write(buffer, 0, n);
}
destination.flush();
destination.close();
return true;
} catch (IOException e) {
return false;
}
}
/**
* This method should only be used when the ByteBuffer is known to be able to accomodate the input!
* @param source
* @param destination
* @return
*/
public static boolean copy(InputStream source, ByteBuffer destination) {
try {
byte [] buffer = new byte[4096];
int n = 0;
while (-1 != (n = source.read(buffer))) {
destination.put(buffer, 0, n);
}
return true;
} catch (IOException e) {
return false;
}
}
/**
* Copy a file or directory.
*
* @param source
* @param destination
* @return true if the operation was successful;
* false otherwise (which includes a null input).
*/
public static boolean copy(File source, File destination) {
boolean result = true;
if (source.isDirectory()) {
if (destination.exists()) {
result = result && destination.isDirectory();
} else {
result = result && destination.mkdirs();
}
File[] children = source.listFiles();
for (File element : children) {
result =
result
&& copy(new File(source, element.getName()),
new File(destination, element.getName()));
}
return result;
} else {
try {
InputStream in = new FileInputStream(source);
OutputStream out = new FileOutputStream(destination);
result = result && copy(in, out);
in.close();
out.close();
return result;
} catch (IOException e) {
return false;
}
}
}
/**
* Create a temporary directory.
*
* @param prefix
* @param directory
* @return
* @throws IOException
*/
public static File createTempDir(String prefix, File directory) throws IOException {
File tempFile = File.createTempFile(prefix, "", directory);
if (!tempFile.delete())
throw new IOException();
if (!tempFile.mkdir())
throw new IOException();
return tempFile;
}
/**
* Delete a File.
*
* @param file
* the File to delete.
* @return true if the operation was successful;
* false otherwise (which includes a null input).
*/
public static boolean delete(File file) {
boolean result = true;
if (file == null) {
return false;
}
if (file.exists()) {
if (file.isDirectory()) {
// 1. delete content of directory:
File[] children = file.listFiles();
for (File child : children) { //for each file:
result = result && delete(child);
}//next file
}
result = result && file.delete();
} //else: input directory does not exist or is not a directory
return result;
}
/**
* Delete the specified file or directory.
*
* @param file
* File or directory to delete
* @return true if the operation was successful;
* false otherwise (which includes a null input).
*/
public static boolean delete(String file) {
return delete(new File(file));
}
public static boolean deleteContents(File dir) {
boolean result = true;
if (dir.exists()) {
for (File f : dir.listFiles()) {
result &= f.delete();
}
} else {
dir.mkdirs();
}
return result;
}
/**
* Move a file or directory. Initally attempts to move the File using
* java.io.File.renameTo(). However, should this operation fail (e.g. when
* source and destination are across different filesystems), will attempt to
* copy and then delete the source.
*
* @param source
* @param destination
* @return true if the operation was successful;
* false otherwise (which includes a null input).
*/
public static boolean move(File source, File destination) {
if (source == null || destination == null) {
return false;
}
if (source.renameTo(destination)) {
return true;
} else {
return copy(source, destination) && delete(source);
}
}
/**
* Load properties from the given file.
*/
public static Properties loadProperties(File f) throws IOException {
Properties props = new Properties();
FileInputStream in = new FileInputStream(f);
try {
props.load(in);
return props;
} finally {
try {
in.close();
} catch (IOException e) {
}
}
}
/**
* Loads a Map from the given Properties file.
*
* @param f
* the Properties file to parse.
* @return a Map representing the given Properties file.
* @throws IOException
* @see java.util.Properties
* @see java.util.Map
*/
public static Map loadMap(File f) throws IOException {
Properties props = new Properties();
FileInputStream in = new FileInputStream(f);
try {
props.load(in);
Map map = new HashMap();
Set> entrySet = props.entrySet();
for (Entry entry : entrySet) {
// The casts to String should always succeed
map.put((String) entry.getKey(), (String) entry.getValue());
}
return map;
} finally {
try {
in.close();
} catch (IOException e) {
}
}
}
public static FileFilter getPrefixFileFilter(String prefix) {
return new PrefixFileFilter(prefix);
}
public static FileFilter getSuffixFileFilter(String suffix) {
return new SuffixFileFilter(suffix);
}
private static class PrefixFileFilter
implements FileFilter {
private final String filenamePrefix;
PrefixFileFilter(String filenamePrefix) {
this.filenamePrefix = filenamePrefix;
}
@Override
public boolean accept(File file) {
String filename = file.getName();
return filename.startsWith(filenamePrefix);
}
}
private static class SuffixFileFilter
implements FileFilter {
private final String filenameSuffix;
SuffixFileFilter(String filenameSuffix) {
this.filenameSuffix = filenameSuffix;
}
@Override
public boolean accept(File file) {
String filename = file.getName();
return filename.endsWith(filenameSuffix);
}
}
}