org.jolokia.jvmagent.client.command.AbstractBaseCommand Maven / Gradle / Ivy
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package org.jolokia.jvmagent.client.command;
/*
* 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 java.util.Properties;
import org.jolokia.jvmagent.JvmAgent;
import org.jolokia.jvmagent.client.util.OptionsAndArgs;
import org.jolokia.jvmagent.client.util.VirtualMachineHandlerOperations;
/**
* Stateless Base command providing helper functions
*
* @author roland
* @since 06.10.11
*/
public abstract class AbstractBaseCommand {
/**
* The name of the command as it can be given on the command line
*
* @return the name of the command
*/
abstract String getName();
/**
* Execute the command
*
* @param pOpts options as given on the command line
* @param pVm the virtual machine object to operate on (as typeless object)
* @param pHandler the handler holding VM operation
* @return 0 in case of a success, 1 otherwise
*
* @throws IllegalAccessException if call via reflection fails
* @throws NoSuchMethodException should not happen since we use well known methods
* @throws InvocationTargetException exception occured during startup of the agent. You probably need to examine
* the stdout of the instrumented process as well for error messages.
*/
abstract int execute(OptionsAndArgs pOpts, Object pVm, VirtualMachineHandlerOperations pHandler) throws InvocationTargetException, NoSuchMethodException, IllegalAccessException;
// =======================================================================================================
/**
* Execute {@code com.sun.tools.attach.VirtualMachine#loadAgent(String, String)}
*
* @param pVm the VirtualMachine object, typeless
* @param pHandler platform-specific way to invoke operations on VM
* @param pOpts options from where to extract the agent path and options
* @param pAdditionalOpts optional additional options to be appended to the agent options. Must be a CSV string.
*/
protected void loadAgent(Object pVm, VirtualMachineHandlerOperations pHandler, OptionsAndArgs pOpts, String ... pAdditionalOpts) {
String args = pOpts.toAgentArg();
if (pAdditionalOpts.length > 0) {
args = args.length() != 0 ? args + "," + pAdditionalOpts[0] : pAdditionalOpts[0];
}
pHandler.loadAgent(pVm, pOpts.getJarFilePath(), args.length() > 0 ? args : null);
}
/**
* Check whether an agent is registered by checking the existance of the system property
* {@link JvmAgent#JOLOKIA_AGENT_URL}. This can be used to check, whether a Jolokia agent
* has been already attached and started. ("start" will set this property, "stop" will remove it).
*
* @param pVm the {@link com.sun.tools.attach.VirtualMachine}, but typeless
* @param pHandler platform-specific way to invoke operations on VM
* @return the agent URL if it is was set by a previous 'start' command.
*/
protected String checkAgentUrl(Object pVm, VirtualMachineHandlerOperations pHandler) {
return checkAgentUrl(pVm, pHandler, 0);
}
/**
* Check whether an agent is registered by checking the existance of the system property
* {@link JvmAgent#JOLOKIA_AGENT_URL}. This can be used to check, whether a Jolokia agent
* has been already attached and started. ("start" will set this property, "stop" will remove it).
*
* @param pVm the {@link com.sun.tools.attach.VirtualMachine}, but typeless
* @param pHandler platform-specific way to invoke operations on VM
* @param delayInMs wait that many ms before fetching the properties
** @return the agent URL if it is was set by a previous 'start' command.
*/
protected String checkAgentUrl(Object pVm, VirtualMachineHandlerOperations pHandler, int delayInMs) {
if (delayInMs != 0) {
try {
Thread.sleep(delayInMs);
} catch (InterruptedException e) {
// just continue
}
}
Properties systemProperties = getAgentSystemProperties(pVm, pHandler);
return systemProperties.getProperty(JvmAgent.JOLOKIA_AGENT_URL);
}
/**
* Execute {@link com.sun.tools.attach.VirtualMachine#getSystemProperties()} via reflection
* @param pVm the VirtualMachine object, typeless
* @param pHandler platform-specific way to invoke operations on VM
* @return the system properties
*/
protected Properties getAgentSystemProperties(Object pVm, VirtualMachineHandlerOperations pHandler) {
return pHandler.getSystemProperties(pVm);
}
/**
* Get a description of the process attached, either the numeric id only or, if a pattern is given,
* the pattern and the associated PID
*
* @param pHandler handler for looking up the process in case of a pattern lookup
* @param pOpts options from where to take the PID or pattern
* @return a description of the process
*/
protected String getProcessDescription(VirtualMachineHandlerOperations pHandler, OptionsAndArgs pOpts) {
if (pOpts.getPid() != null) {
return "PID " + pOpts.getPid();
} else if (pOpts.getProcessPattern() != null) {
StringBuffer desc = new StringBuffer("process matching \"")
.append(pOpts.getProcessPattern().pattern())
.append("\"");
desc.append(" (PID: ")
.append(pHandler.findProcess(pOpts.getProcessPattern()).getId())
.append(")");
return desc.toString();
} else {
return "(null)";
}
}
}