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/**
* Files
* Copyright 2011 by Michael Peter Christen, mc@yacy.net, Frankfurt a. M., Germany
* First released 29.06.2011 at http://yacy.net
*
* $LastChangedDate: 2011-05-30 10:53:58 +0200 (Mo, 30 Mai 2011) $
* $LastChangedRevision: 7759 $
* $LastChangedBy: orbiter $
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program in the file lgpl21.txt
* If not, see <http://www.gnu.org/licenses/>.
*/
package net.yacy.cora.storage;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.zip.GZIPInputStream;
import org.apache.commons.compress.compressors.bzip2.BZip2CompressorInputStream;
public class Files {
/**
* open text files for reading. If the files are compressed, choose the
* appropriate decompression method automatically
* @param f
* @return the input stream for the file
* @throws IOException
*/
public static InputStream read(File f) throws IOException {
// make input stream
InputStream is = new BufferedInputStream(new FileInputStream(f));
if (f.toString().endsWith(".bz2")) is = new BZip2CompressorInputStream(is);
if (f.toString().endsWith(".gz")) is = new GZIPInputStream(is);
return is;
}
/**
* reading a file line by line should be done with two concurrent processes
* - one reading the file and doing IO operations
* - one processing the result
* This method makes is easy to create concurrent file readers by providing
* a process that fills a blocking queue with lines from a file.
* After the method is called, it returns immediately a blocking queue which is
* filled concurrently with the lines of the file. When the reading is finished,
* this is signalled with a poison entry, the POISON_LINE String which can be
* compared with an "==" operation.
* @param f the file to read
* @param maxQueueSize
* @return a blocking queue which is filled with the lines, terminated by POISON_LINE
* @throws IOException
*/
public final static String POISON_LINE = "__@POISON__";
public static BlockingQueue<String> concurentLineReader(final File f) throws IOException {
final BlockingQueue<String> q = new LinkedBlockingQueue<String>();
final InputStream is = read(f);
final BufferedReader br = new BufferedReader(new InputStreamReader(is, StandardCharsets.UTF_8));
Thread t = new Thread("Files.concurrentLineReader:" + f) {
@Override
public void run() {
String line;
try {
while ((line = br.readLine()) != null) {
q.put(line);
}
} catch (final IOException e) {
} catch (final InterruptedException e) {
} finally {
try {
q.put(POISON_LINE);
try {
br.close();
is.close();
} catch (final IOException ee) {
}
} catch (final InterruptedException e) {
// last try
q.add(POISON_LINE);
try {
br.close();
is.close();
} catch (final IOException ee) {
}
}
}
}
};
t.start();
return q;
}
/**
* copy a file or a complete directory
* @param from the source file or directory
* @param to the destination file or directory
* @throws IOException
*/
public static void copy(final File from, final File to) throws IOException {
if (!from.exists()) {
throw new IOException("Can not find source: " + from.getAbsolutePath()+".");
} else if (!from.canRead()) {
throw new IOException("No right to source: " + from.getAbsolutePath()+".");
}
if (from.isDirectory()) {
if (!to.exists() && !to.mkdirs()) {
throw new IOException("Could not create directory: " + to.getAbsolutePath() + ".");
}
for (final String f : from.list()) {
copy(new File(from, f) , new File(to, f));
}
} else {
if (to.isDirectory()) throw new IOException("Cannot copy a file to an existing directory");
if (to.exists()) to.delete();
final byte[] buffer = new byte[4096];
int bytesRead;
InputStream in = null;
OutputStream out = null;
try {
in = new BufferedInputStream(new FileInputStream(from));
out = new BufferedOutputStream(new FileOutputStream (to));
while ((bytesRead = in.read(buffer)) >= 0) {
out.write(buffer,0,bytesRead);
}
} finally {
if(in != null) {
try {
in.close();
} catch(IOException ignored) {
}
}
if(out != null) {
out.close();
}
}
}
}
}
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