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@chrixian chrixian/Agent.java
Created Feb 6, 2014

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import com.sun.tools.attach.AgentInitializationException;
import com.sun.tools.attach.AgentLoadException;
import com.sun.tools.attach.AttachNotSupportedException;
import com.sun.tools.attach.VirtualMachine;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.lang.management.ManagementFactory;
import java.lang.management.RuntimeMXBean;
import java.util.Properties;
import java.util.jar.Attributes;
import java.util.jar.JarOutputStream;
import java.util.jar.Manifest;
/**
* User: Tyler Sedlar, TSedlar
* License: Creative Commons Attribution 3.0 Unported License
* Date: 11/10/13
* Time: 9:32 AM
*/
public class Agent {
public final String pid;
public final Manifest manifest;
public final File jar;
public final VirtualMachine vm;
public final Properties properties;
private boolean detached = false;
private String getPid() {
RuntimeMXBean bean = ManagementFactory.getRuntimeMXBean();
String pid = bean.getName();
if (pid.contains("@")) {
pid = pid.substring(0, pid.indexOf("@"));
}
return pid;
}
public Agent(Class<?> agent) throws IOException, AttachNotSupportedException, AgentLoadException, AgentInitializationException {
this.pid = getPid();
this.manifest = new Manifest();
this.jar = File.createTempFile("agent-" + pid, ".jar");
jar.deleteOnExit();
Attributes attributes = manifest.getMainAttributes();
attributes.put(Attributes.Name.MANIFEST_VERSION, "1.0");
attributes.put(new Attributes.Name("Agent-Class"), agent.getName());
attributes.put(new Attributes.Name("Can-Retransform-Classes"), "true");
attributes.put(new Attributes.Name("Can-Redefine-Classes"), "true");
try (JarOutputStream output = new JarOutputStream(new FileOutputStream(jar), manifest)) {
output.flush();
}
this.vm = VirtualMachine.attach(pid);
this.properties = vm.getSystemProperties();
vm.loadAgent(jar.getAbsolutePath());
Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
public void run() {
try {
detached = true;
vm.detach();
System.out.println("Agent#" + pid + " detached");
} catch (IOException e) {
e.printStackTrace();
}
}
}));
}
public void detach() {
detached = true;
}
public boolean attached() {
return !detached;
}
}
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