com.sleepycat.utilint.StatLogger Maven / Gradle / Ivy
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/*-
* Copyright (C) 2002, 2018, Oracle and/or its affiliates. All rights reserved.
*
* This file was distributed by Oracle as part of a version of Oracle Berkeley
* DB Java Edition made available at:
*
* http://www.oracle.com/technetwork/database/database-technologies/berkeleydb/downloads/index.html
*
* Please see the LICENSE file included in the top-level directory of the
* appropriate version of Oracle Berkeley DB Java Edition for a copy of the
* license and additional information.
*/
package com.sleepycat.utilint;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import com.sleepycat.je.EnvironmentFailureException;
public class StatLogger {
private final File logFile;
private final String fileext;
private final String filename;
private final File logDir;
private int maxFileCount;
private int maxRowCount;
private String header = null;
private String lastVal = null;
private int currentRowCount;
/**
* StatLogger is used to write to a log file that contain a header followed
* by a set of data rows. Parameters control the size and number of
* rotating log files used. For a rotating set of files, as each file
* reaches a given size limit, it is closed, rotated out, and a new
* file opened. The name of the log file is filename.fileext. Successively
* older files are named by adding "0", "1", "2", etc into the file name.
* The format is filename.[version number].fileext.
*
* @param logdir Log file directory.
* @param filename Name of the log file.
* @param fileext Extent of the log file.
* @param filecount Maximum number of rotating log files to be saved.
* @param rowcount Maximum number of rows in a log file.
*
* @throws IOException if log file or directory cannot be accessed.
* @throws IllegalArgumentException if the log directory is not
* a directory or if the log file is not a file.
*/
public StatLogger(File logdir,
String filename,
String fileext,
int filecount,
int rowcount) throws IOException {
logFile = new File(logdir.getAbsolutePath() + File.separator +
filename + "." + fileext);
this.maxFileCount = filecount - 1;
this.maxRowCount = rowcount;
this.filename = filename;
this.fileext = fileext;
this.logDir = logdir;
if (logFile.exists()) {
if (!logFile.isFile()) {
throw new IllegalArgumentException(
"Statistic log file" + logFile.getAbsolutePath() +
" exists but is not a file.");
}
header = getHeader();
/* set current row count. */
getLastRow();
}
}
/**
* Sets the maximum log file row count.
*
* @param rowcount The maximum number of rows per log file.
*/
public void setRowCount(int rowcount) {
maxRowCount = rowcount;
}
/**
* Set the maximum number of log files to keep after rotation.
*
* @param filecount The maximum number of log files to keep.
*/
public void setFileCount(int filecount) {
filecount--;
if (maxFileCount > filecount) {
/* remove files that are greater then the new filecount */
for (int i = maxFileCount; i > filecount; i--) {
File deleme = new File(formFn(i - 2));
if (deleme.exists()) {
deleme.delete();
}
}
}
maxFileCount = filecount;
}
/**
* Sets the log file header. A new log file may be created if
* the header does not match the header in the existing file.
*
* @param val Header row data.
*
* @throws IOException
*/
public void setHeader(String val) throws IOException {
if (!val.equals(header)) {
if (header != null) {
/* file headers are different so rotate files */
rotateFiles();
}
currentRowCount++;
write(val);
header = val;
lastVal = null;
}
}
/**
* log writes the string to the log file.
*
* @param val Value to write to the log.
* @throws IOException
*/
public void log(String val) throws IOException {
if (currentRowCount >= maxRowCount)
{
rotateFiles();
currentRowCount++;
write(header);
}
currentRowCount++;
write(val);
lastVal = val;
}
/**
* logDelta writes the string if the string is different
* than the last written log record. The first column is
* ignored when checking for a difference (current
* implementation has the time the record is logged as the
* first column.
*
* @param val value write to the log.
* @throws IOException
*/
public void logDelta(String val) throws IOException {
if (header == null) {
throw EnvironmentFailureException.unexpectedState(
"Unexpected state logHeader not called before logDelta.");
}
if (lastVal == null) {
lastVal = getLastRow();
}
String lastNoFirst = null;
if (lastVal != null) {
lastNoFirst = lastVal.substring(lastVal.indexOf(',') + 1);
}
if (!val.substring(val.indexOf(',') + 1).equals(lastNoFirst)) {
log(val);
}
}
private String getHeader() throws IOException {
String header;
BufferedReader fr = null;
try {
fr = new BufferedReader(new FileReader(logFile));
header = fr.readLine();
} catch (FileNotFoundException e) {
throw new IOException(
"Error occured accessing statistic log file " +
"FileNotFoundException " +
logFile.getAbsolutePath(), e);
} finally {
if (fr != null) {
try {
fr.close();
}
catch (IOException e) {
/* eat exception */
}
}
}
return header;
}
private String getLastRow() throws IOException {
String row;
BufferedReader fr = null;
currentRowCount = 0;
try {
fr = new BufferedReader(new FileReader(logFile));
String prevrow = null;
while ((row = fr.readLine()) != null) {
currentRowCount++;
prevrow = row;
}
return prevrow;
} catch (FileNotFoundException e) {
throw new IOException(
"Error occured accessing statistic log file " +
"FileNotFoundException " +
logFile.getAbsolutePath(), e);
} finally {
if (fr != null) {
try {
fr.close();
}
catch (IOException e) {
/* eat exception */
}
}
}
}
private String formFn(int version) {
if (version < 0) {
return logDir.getAbsolutePath() + File.separator +
filename + "." + fileext;
} else {
return logDir.getAbsolutePath() + File.separator + filename +
"." + version + "." + fileext;
}
}
private void write(String val) throws IOException
{
PrintWriter ps = null;
try {
ps = new PrintWriter(new FileWriter(logFile, true));
ps.println(val);
} catch (FileNotFoundException e) {
throw new IOException(
"Error occured accessing statistic log file " +
"FileNotFoundException " +
logFile.getAbsolutePath(), e);
} finally {
if (ps != null) {
ps.flush();
ps.close();
}
}
}
private void rotateFiles() {
File cf = new File(formFn(maxFileCount - 1));
if (cf.exists()) {
cf.delete();
}
for (int i = maxFileCount - 2; i >= -1; i--) {
cf = new File(formFn(i));
if (cf.exists()) {
cf.renameTo(new File(formFn(i + 1)));
}
}
currentRowCount = 0;
}
}
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