yacy_search_server/source/net/yacy/kelondro/io/CachedFileReader.java
Michael Peter Christen 5878c1d599 - refactoring of log to ConcurrentLog:
jdk-based logger tend to block
at java.util.logging.Logger.log(Logger.java:476) in concurrent
environments. This makes logging a main performance issue. To overcome
this problem, this is a add-on to jdk logging to put log entries on a
concurrent message queue and log the messages one by one using a
separate process.
- FTPClient uses the concurrent logging instead of the log4j logger
2013-07-09 14:28:25 +02:00

94 lines
3.0 KiB
Java

// CachedFileReader.java
// ---------------------
// (C) 2009 by Michael Peter Christen; mc@yacy.net
// first published 09.09.2009 on http://yacy.net
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package net.yacy.kelondro.io;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import net.yacy.cora.util.ConcurrentLog;
import net.yacy.kelondro.util.MemoryControl;
public final class CachedFileReader extends AbstractReader implements Reader {
private final RandomAccessFile RAFile;
private byte[] cache;
private final int cachelen;
public CachedFileReader(final File file) throws IOException, FileNotFoundException {
this.name = file.getName();
this.file = file;
this.RAFile = new RandomAccessFile(this.file, "r");
if (MemoryControl.available() / 10L > this.RAFile.length() && this.RAFile.length() < Integer.MAX_VALUE) {
this.cache = new byte[(int) this.RAFile.length()];
this.RAFile.seek(0);
this.RAFile.readFully(this.cache);
} else {
this.cache = null;
}
this.cachelen = 0;
}
public final synchronized long available() throws IOException {
return this.length() - RAFile.getFilePointer();
}
public final synchronized long length() throws IOException {
return this.RAFile.length();
}
public final synchronized void readFully(final byte[] b, final int off, int len) throws IOException {
long seek = RAFile.getFilePointer();
if (cache != null && cachelen - seek >= len) {
// read from cache
System.arraycopy(cache, (int) (seek), b, off, len);
RAFile.seek(seek + len);
return;
}
// cannot use the cache
RAFile.readFully(b, off, len);
return;
}
public final synchronized void seek(final long pos) throws IOException {
RAFile.seek(pos);
}
public final synchronized void close() {
if (RAFile != null) try {
try{RAFile.getChannel().close();} catch (IOException e) {}
RAFile.close();
} catch (IOException e) {
ConcurrentLog.logException(e);
}
this.cache = null;
}
@Override
protected void finalize() throws Throwable {
this.close();
super.finalize();
}
}