package org.slf4j.agent;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.lang.instrument.Instrumentation;
import java.util.Date;
import java.util.Properties;
import org.slf4j.instrumentation.LogTransformer;
/**
* Entry point for slf4j-ext when used as a Java agent.
*
*/
public class AgentPremain {
/**
* JavaAgent premain entry point as specified in the MANIFEST.MF file. See
* {@link http
* ://java.sun.com/javase/6/docs/api/java/lang/instrument/package-
* summary.html} for details.
*
* @param agentArgument
* string provided after "=" up to first space
* @param instrumentation
* instrumentation environment provided by the JVM
*/
public static void premain(String agentArgument,
Instrumentation instrumentation) {
// We cannot do sanity checks for slf4j here as the jars loaded
// by the application are not visible here.
LogTransformer.Builder builder = new LogTransformer.Builder();
builder = builder.addEntryExit(true);
if (agentArgument != null) {
Properties args = parseArguments(agentArgument, ",");
if (args.containsKey(AgentOptions.VERBOSE)) {
builder = builder.verbose(true);
}
if (args.containsKey(AgentOptions.TIME)) {
printStartStopTimes();
}
if (args.containsKey(AgentOptions.IGNORE)) {
String ignore = args.getProperty(AgentOptions.IGNORE);
builder = builder.ignore(ignore.split(":"));
}
if (args.containsKey(AgentOptions.LEVEL)) {
builder = builder.level(args.getProperty(AgentOptions.LEVEL));
}
}
instrumentation.addTransformer(builder.build());
}
/**
* Consider the argument string to be a property file (by converting the
* splitter character to line feeds), and then reading it like any other
* property file.
*
*
* @param agentArgument
* string given by instrumentation framework
* @param separator
* String to convert to line feeds
* @return argument converted to properties
*/
private static Properties parseArguments(String agentArgument,
String separator) {
Properties p = new Properties();
try {
String argumentAsLines = agentArgument.replaceAll(separator, "\n");
p.load(new ByteArrayInputStream(argumentAsLines.getBytes()));
} catch (IOException e) {
String s = "Could not load arguments as properties";
throw new RuntimeException(s, e);
}
return p;
}
/**
* Print the start message to System.err with the time NOW, and register a
* shutdown hook which will print the stop message to System.err with the
* time then and the number of milliseconds passed since.
*
*/
private static void printStartStopTimes() {
final long start = System.currentTimeMillis();
System.err.println("Start at " + new Date());
Thread hook = new Thread() {
@Override
public void run() {
long timePassed = System.currentTimeMillis() - start;
System.err.println("Stop at " + new Date()
+ ", execution time = " + timePassed + " ms");
}
};
Runtime.getRuntime().addShutdownHook(hook);
}
}