Back to index...

	/*
	* Copyright (c) 2005, 2013, 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 com.sun.management;

	import sun.management.VMOptionCompositeData;
	import javax.management.openmbean.CompositeData;

	/**
	* Information about a VM option including its value and
	* where the value came from which is referred as its
	* {@link VMOption.Origin <i>origin</i>}.
	* <p>
	* Each VM option has a default value. A VM option can
	* be set at VM creation time typically as a command line
	* argument to the launcher or an argument passed to the
	* VM created using the JNI invocation interface.
	* In addition, a VM option may be set via an environment
	* variable or a configuration file. A VM option can also
	* be set dynamically via a management interface after
	* the VM was started.
	*
	* A <tt>VMOption</tt> contains the value of a VM option
	* and the origin of that value at the time this <tt>VMOption</tt>
	* object was constructed. The value of the VM option
	* may be changed after the <tt>VMOption</tt> object was constructed,
	*
	* @see <a href="{@docRoot}/../../../../technotes/guides/vm/index.html">
	* Java Virtual Machine</a>
	* @author Mandy Chung
	* @since 1.6
	*/
	@jdk.Exported
	public class VMOption {
	private String name;
	private String value;
	private boolean writeable;
	private Origin origin;

	/**
	* Origin of the value of a VM option. It tells where the
	* value of a VM option came from.
	*
	* @since 1.6
	*/
	@jdk.Exported
	public enum Origin {
	/**
	* The VM option has not been set and its value
	* is the default value.
	*/
	DEFAULT,
	/**
	* The VM option was set at VM creation time typically
	* as a command line argument to the launcher or
	* an argument passed to the VM created using the
	* JNI invocation interface.
	*/
	VM_CREATION,
	/**
	* The VM option was set via an environment variable.
	*/
	ENVIRON_VAR,
	/**
	* The VM option was set via a configuration file.
	*/
	CONFIG_FILE,
	/**
	* The VM option was set via the management interface after the VM
	* was started.
	*/
	MANAGEMENT,
	/**
	* The VM option was set via the VM ergonomic support.
	*/
	ERGONOMIC,
	/**
	* The VM option was set via some other mechanism.
	*/
	OTHER
	}

	/**
	* Constructs a <tt>VMOption</tt>.
	*
	* @param name Name of a VM option.
	* @param value Value of a VM option.
	* @param writeable <tt>true</tt> if a VM option can be set dynamically,
	* or <tt>false</tt> otherwise.
	* @param origin where the value of a VM option came from.
	*
	* @throws NullPointerException if the name or value is <tt>null</tt>
	*/
	public VMOption(String name, String value, boolean writeable, Origin origin) {
	this.name = name;
	this.value = value;
	this.writeable = writeable;
	this.origin = origin;
	}

	/**
	* Constructs a <tt>VMOption</tt> object from a
	* {@link CompositeData CompositeData}.
	*/
	private VMOption(CompositeData cd) {
	// validate the input composite data
	VMOptionCompositeData.validateCompositeData(cd);

	this.name = VMOptionCompositeData.getName(cd);
	this.value = VMOptionCompositeData.getValue(cd);
	this.writeable = VMOptionCompositeData.isWriteable(cd);
	this.origin = VMOptionCompositeData.getOrigin(cd);
	}

	/**
	* Returns the name of this VM option.
	*
	* @return the name of this VM option.
	*/
	public String getName() {
	return name;
	}

	/**
	* Returns the value of this VM option at the time when
	* this <tt>VMOption</tt> was created. The value could have been changed.
	*
	* @return the value of the VM option at the time when
	* this <tt>VMOption</tt> was created.
	*/
	public String getValue() {
	return value;
	}

	/**
	* Returns the origin of the value of this VM option. That is,
	* where the value of this VM option came from.
	*
	* @return where the value of this VM option came from.
	*/
	public Origin getOrigin() {
	return origin;
	}

	/**
	* Tests if this VM option is writeable. If this VM option is writeable,
	* it can be set by the {@link HotSpotDiagnosticMXBean#setVMOption
	* HotSpotDiagnosticMXBean.setVMOption} method.
	*
	* @return <tt>true</tt> if this VM option is writeable; <tt>false</tt>
	* otherwise.
	*/
	public boolean isWriteable() {
	return writeable;
	}

	public String toString() {
	return "VM option: " + getName() +
	" value: " + value + " " +
	" origin: " + origin + " " +
	(writeable ? "(read-write)" : "(read-only)");
	}

	/**
	* Returns a <tt>VMOption</tt> object represented by the
	* given <tt>CompositeData</tt>. The given <tt>CompositeData</tt>
	* must contain the following attributes:
	* <p>
	* <blockquote>
	* <table border>
	* <tr>
	* <th align=left>Attribute Name</th>
	* <th align=left>Type</th>
	* </tr>
	* <tr>
	* <td>name</td>
	* <td><tt>java.lang.String</tt></td>
	* </tr>
	* <tr>
	* <td>value</td>
	* <td><tt>java.lang.String</tt></td>
	* </tr>
	* <tr>
	* <td>origin</td>
	* <td><tt>java.lang.String</tt></td>
	* </tr>
	* <tr>
	* <td>writeable</td>
	* <td><tt>java.lang.Boolean</tt></td>
	* </tr>
	* </table>
	* </blockquote>
	*
	* @param cd <tt>CompositeData</tt> representing a <tt>VMOption</tt>
	*
	* @throws IllegalArgumentException if <tt>cd</tt> does not
	* represent a <tt>VMOption</tt> with the attributes described
	* above.
	*
	* @return a <tt>VMOption</tt> object represented by <tt>cd</tt>
	* if <tt>cd</tt> is not <tt>null</tt>;
	* <tt>null</tt> otherwise.
	*/
	public static VMOption from(CompositeData cd) {
	if (cd == null) {
	return null;
	}

	if (cd instanceof VMOptionCompositeData) {
	return ((VMOptionCompositeData) cd).getVMOption();
	} else {
	return new VMOption(cd);
	}

	}


	}

Back to index...