/*
* The MIT License
*
* Copyright (c) 2004-2009, Sun Microsystems, Inc., Kohsuke Kawaguchi
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package hudson.util;
import java.util.AbstractList;
import java.util.List;
import java.util.logging.Handler;
import java.util.logging.LogRecord;
/**
* Log {@link Handler} that stores the log records into a ring buffer.
*
* @author Kohsuke Kawaguchi
*/
public class RingBufferLogHandler extends Handler {
private int start = 0;
private final LogRecord[] records;
private volatile int size = 0;
public RingBufferLogHandler() {
this(256);
}
public RingBufferLogHandler(int ringSize) {
records = new LogRecord[ringSize];
}
public synchronized void publish(LogRecord record) {
int len = records.length;
records[(start+size)%len]=record;
if(size==len) {
start++;
} else {
size++;
}
}
/**
* Returns the list view of {@link LogRecord}s in the ring buffer.
*
* <p>
* New records are always placed early in the list.
*/
public List<LogRecord> getView() {
return new AbstractList<LogRecord>() {
public LogRecord get(int index) {
// flip the order
synchronized (RingBufferLogHandler.this) {
return records[(start+(size-(index+1)))%records.length];
}
}
public int size() {
return size;
}
};
}
// noop
public void flush() {}
public void close() throws SecurityException {}
}