/*
* Copyright (c) 2010-2012 Grid Dynamics Consulting Services, Inc, All Rights Reserved
* http://www.griddynamics.com
*
* This library is free software; you can redistribute it and/or modify it under the terms of
* the Apache License; either
* version 2.0 of the License, or any later version.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.griddynamics.jagger.storage.fs.timelog;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicBoolean;
import com.griddynamics.jagger.exception.TechnicalException;
import org.apache.log4j.Logger;
/**
* This class in intended for writing logs in format (timestamp | value1 | value2 | ...)
* where values are floating point numbers.
*
*/
public class NumericalTimeLogWriter {
private static final Logger log = Logger.getLogger(NumericalTimeLogWriter.class);
private String delimiter = "|";
private int maxBufferSize = 10000;
private final BlockingQueue<Entry> buffer = new ArrayBlockingQueue<Entry>(maxBufferSize);
private final AtomicBoolean flushActive = new AtomicBoolean(false);
private List<DataOutputStream> streams;
/**
* Creates log writer for multiple output stream
* @param streams list of output streams. Data output will be randomly distributed among streams
*/
public NumericalTimeLogWriter(List<DataOutputStream> streams) {
this.streams = streams;
}
public NumericalTimeLogWriter(DataOutputStream stream) {
this(Collections.singletonList(stream));
}
/**
* Add new entry to the output queue.
*/
public void write(long timestamp, double[] values) {
try {
buffer.put(new Entry(timestamp, values));
} catch (InterruptedException e) {
throw new TechnicalException(e);
}
}
private void writeEntry(Entry entry, DataOutputStream stream) {
try {
String line = entry.timestamp + delimiter;
for(Object value : entry.values) {
line += value + delimiter;
}
stream.writeUTF(line + '\n');
} catch(IOException e) {
throw new TechnicalException(e);
}
}
/**
* Starts background process of data flushing to the output streams. Should be called before writing -
* otherwise writing will be blocked after {@link #maxBufferSize} writes.
*/
public void startFlushing() {
flushActive.set(true);
for(int i = 0; i < streams.size(); i++) {
final int streamId = i;
new Thread() {
public void run() {
while(flushActive.get()) {
try {
Entry entry = buffer.take();
writeEntry(entry, streams.get(streamId));
} catch (InterruptedException e) {
log.error("Flushing thread was interrupted", e);
}
}
}
}.start();
}
}
private void terminateFlush() {
flushActive.set(false);
}
/**
* Stop flushing threads, drain buffer and close all output data streams.
*/
public void close() {
terminateFlush();
try {
while(!buffer.isEmpty()) {
Entry entry = buffer.take();
writeEntry(entry, streams.get(0));
}
} catch (InterruptedException e) {
log.error("Final flushing was interrupted. About [" + buffer.size() + "] entries can be lost.", e);
}
for(DataOutputStream stream : streams) {
try {
stream.close();
} catch (Exception e) {
log.error("Failed to close stream", e);
}
}
}
private static class Entry {
public long timestamp;
public double values[];
public Entry(long timestamp, double values[]) {
this.timestamp = timestamp;
this.values = values;
}
}
// -----------------------------------------------------------------------------------------------------------------
public String getDelimiter() {
return delimiter;
}
public void setDelimiter(String delimiter) {
this.delimiter = delimiter;
}
public int getMaxBufferSize() {
return maxBufferSize;
}
public void setMaxBufferSize(int maxBufferSize) {
this.maxBufferSize = maxBufferSize;
}
}