/*
* Copyright (c) 2005, 2006, 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
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*/
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
*/
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
*/
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-only)" : "(read-write)");
}
/**
* 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);
}
}
}