net.java.btrace.ext.sys.VM Maven / Gradle / Ivy
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/*
* Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package net.java.btrace.ext.sys;
import net.java.btrace.ext.Printer;
import net.java.btrace.api.extensions.BTraceExtension;
import net.java.btrace.api.extensions.runtime.Runtime;
import java.util.List;
import javax.annotation.Resource;
import net.java.btrace.api.extensions.runtime.MBeans;
import net.java.btrace.api.extensions.runtime.Objects;
/*
* Wraps the VM related BTrace utility methods
* @since 1.3
* @author A. Sundararajan
* @author Jaroslav Bachorik
*/
@BTraceExtension
public class VM {
@Resource
private static MBeans mbeans;
@Resource
private static Runtime rt;
@Resource
private static Objects objects;
/**
* Returns the input arguments passed to the Java virtual machine
* which does not include the arguments to the main method.
* This method returns an empty list if there is no input argument
* to the Java virtual machine.
*
* Some Java virtual machine implementations may take input arguments
* from multiple different sources: for examples, arguments passed from
* the application that launches the Java virtual machine such as
* the 'java' command, environment variables, configuration files, etc.
*
* Typically, not all command-line options to the 'java' command
* are passed to the Java virtual machine.
* Thus, the returned input arguments may not
* include all command-line options.
*
* @return a list of String objects; each element
* is an argument passed to the Java virtual machine.
*/
public static List vmArguments() {
return mbeans.getRuntimeMBean().getInputArguments();
}
/**
* Prints VM input arguments list.
*
* @see #vmArguments
*/
public static void printVmArguments() {
Printer.println(vmArguments());
}
/**
* Returns the Java virtual machine implementation version.
* This method is equivalent to Sys.getProperty("java.vm.version")}.
*
* @return the Java virtual machine implementation version.
*/
public static String vmVersion() {
return mbeans.getRuntimeMBean().getVmVersion();
}
/**
* Tests if the Java virtual machine supports the boot class path
* mechanism used by the bootstrap class loader to search for class
* files.
*
* @return true if the Java virtual machine supports the
* class path mechanism; false otherwise.
*/
public static boolean isBootClassPathSupported() {
return mbeans.getRuntimeMBean().isBootClassPathSupported();
}
/**
* Returns the boot class path that is used by the bootstrap class loader
* to search for class files.
*
* Multiple paths in the boot class path are separated by the
* path separator character of the platform on which the Java
* virtual machine is running.
*
*
A Java virtual machine implementation may not support
* the boot class path mechanism for the bootstrap class loader
* to search for class files.
* The {@link #isBootClassPathSupported} method can be used
* to determine if the Java virtual machine supports this method.
*
* @return the boot class path.
* @throws java.lang.UnsupportedOperationException
* if the Java virtual machine does not support this operation.
*/
public static String bootClassPath() {
return mbeans.getRuntimeMBean().getBootClassPath();
}
/**
* Returns the Java class path that is used by the system class loader
* to search for class files.
* This method is equivalent to Sys.getProperty("java.class.path").
*
* @return the Java class path.
*/
public static String classPath() {
return Env.property("java.class.path");
}
/**
* Returns the Java library path.
* This method is equivalent to Sys.getProperty("java.library.path").
*
*
Multiple paths in the Java library path are separated by the
* path separator character of the platform of the Java virtual machine
* being monitored.
*
* @return the Java library path.
*/
public static String libraryPath() {
return Env.property("java.library.path");
}
/**
* Returns the start time of the Java virtual machine in milliseconds.
* This method returns the approximate time when the Java virtual
* machine started.
*
* @return start time of the Java virtual machine in milliseconds.
*/
public static long vmStartTime() {
return mbeans.getRuntimeMBean().getStartTime();
}
/**
* Returns the uptime of the Java virtual machine in milliseconds.
*
* @return uptime of the Java virtual machine in milliseconds.
*/
public static long vmUptime() {
return mbeans.getRuntimeMBean().getUptime();
}
// BTrace exit built-in function
public static void exit(int exitCode) {
rt.exit(exitCode);
}
/**
* Returns the class loader for the given class. Some implementations may use
* null to represent the bootstrap class loader. This method will return
* null in such implementations if this class was loaded by the bootstrap
* class loader.
*
* @param clazz the Class for which the class loader is returned
*/
public static ClassLoader loader(Class clazz) {
return clazz.getClassLoader();
}
/**
* Returns the parent class loader of the given loader. Some implementations may
* use null to represent the bootstrap class loader. This method
* will return null in such implementations if this class loader's
* parent is the bootstrap class loader.
*
* @param loader the loader for which the parent loader is returned
* @return The parent ClassLoader
*/
public static ClassLoader parentLoader(ClassLoader loader) {
return loader.getParent();
}
/**
* Returns identity string of the form class-name@identity-hash
*
* @param obj object for which identity string is returned
* @return identity string
*/
public static String identityStr(Object obj) {
return identityStr(obj);
}
/**
* Returns the shallow size of the given object
* @param obj object for which the sizeof is to be calculated
* @return the shallow object size
*/
public static long sizeof(Object obj) {
return objects.sizeof(obj);
}
/**
* Returns a hash code value for the object. This method is supported
* for the benefit of hashtables such as those provided by
* java.util.Hashtable. For bootstrap classes, returns the
* result of calling Object.hashCode() override. For non-bootstrap classes,
* the identity hash code is returned.
*
* @param obj the Object whose hash code is returned.
* @return a hash code value for the given object.
*/
public static int hash(Object obj) {
return objects.hash(obj);
}
/**
* Returns the same hash code for the given object as
* would be returned by the default method hashCode(),
* whether or not the given object's class overrides
* hashCode(). The hash code for the null reference is zero.
*
* @param obj object for which the hashCode is to be calculated
* @return the hashCode
*/
public static int identityHashCode(Object obj) {
return objects.identityHashCode(obj);
}
/**
* Indicates whether two given objects are "equal to" one another.
* For bootstrap classes, returns the result of calling Object.equals()
* override. For non-bootstrap classes, the reference identity comparison
* is done.
*
* @param obj1 first object to compare equality
* @param obj2 second object to compare equality
* @return true if the given objects are equal;
* false otherwise.
*/
public static boolean compare(Object obj1, Object obj2) {
return objects.compare(obj1, obj2);
}
}