org.jolokia.jvmagent.client.AgentLauncher Maven / Gradle / Ivy
package org.jolokia.jvmagent.client;
/*
* Copyright 2009-2013 Roland Huss
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.lang.reflect.InvocationTargetException;
import org.jolokia.jvmagent.client.util.*;
import org.jolokia.jvmagent.client.command.CommandDispatcher;
/**
* Launcher for attaching/detaching a Jolokia agent dynamically to an already
* running Java process.
*
* This launcher tries hard to detect the required classes from tools.jar dynamically. For Mac OSX
* these classes are already included, for other they are looked up within JAVA_HOME
* (pointed to by the system property java.home). Classes from tools.jar are never
* referenced directly but looked up via reflection.
*
* @author roland, Greg Bowyer
* @since 28.07.11
*/
@SuppressWarnings({"PMD.AvoidDuplicateLiterals","PMD.SystemPrintln"})
public final class AgentLauncher {
private AgentLauncher() { }
/**
* Main method for attaching agent to a running JVM program. Use '--help' for a usage
* explanation.
*
* @param args command line arguments
*/
// We use processing exception thrown here for better error reporting, not flow control.
@SuppressWarnings("PMD.ExceptionAsFlowControl")
public static void main(String... args) {
OptionsAndArgs options;
try {
options = new OptionsAndArgs(CommandDispatcher.getAvailableCommands(),args);
VirtualMachineHandlerOperations vmHandler = PlatformUtils.createVMAccess(options);
CommandDispatcher dispatcher = new CommandDispatcher(options);
// Attach a VirtualMachine to a given PID (if PID is given)
Object vm = options.needsVm() ? vmHandler.attachVirtualMachine() : null;
// Dispatch command
int exitCode = 0;
try {
exitCode = dispatcher.dispatchCommand(vm,vmHandler);
} catch (InvocationTargetException e) {
throw new ProcessingException("InvocationTargetException",e,options);
} catch (NoSuchMethodException e) {
throw new ProcessingException("Internal: NoSuchMethod",e,options);
} catch (IllegalAccessException e) {
throw new ProcessingException("IllegalAccess",e,options);
} finally {
if (vm != null) {
vmHandler.detachAgent(vm);
}
}
System.exit(exitCode);
} catch (IllegalArgumentException exp) {
System.err.println("Error: " + exp.getMessage() + "\n");
CommandDispatcher.printHelp();
System.exit(1);
} catch (ProcessingException exp) {
exp.printErrorMessage();
System.exit(1);
}
}
}