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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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package com.sun.management;

import com.sun.management.internal.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 origin. 
 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 VMOption contains the value of a VM option and the origin of that value at the time this VMOption object was constructed. The value of the VM option may be changed after the VMOption object was constructed, 
Author:Mandy Chung
Since:1.6
/**
 * 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 {@code VMOption} contains the value of a VM option
 * and the origin of that value at the time this {@code VMOption}
 * object was constructed.  The value of the VM option
 * may be changed after the {@code VMOption} object was constructed,
 *
 * @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
/**
     * 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.

/**
         * 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.

/**
         * 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.

/**
         * The VM option was set via an environment variable.
         */
        ENVIRON_VAR,
        
The VM option was set via a configuration file.

/**
         * 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.

/**
         * 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.

/**
         * The VM option was set via the VM ergonomic support.
         */
        ERGONOMIC,
        
The VM option was set using the attach framework.

Since:9
/**
         * The VM option was set using the attach framework.
         * @since 9
         */
        ATTACH_ON_DEMAND,
        
The VM option was set via some other mechanism.

/**
         * The VM option was set via some other mechanism.
         */
        OTHER
    }

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

    
Constructs a VMOption object from a CompositeData. 
/**
     * Constructs a {@code VMOption} 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.

Returns:the name of this VM option.
/**
     * 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 VMOption was created. The value could have been changed. 
Returns:the value of the VM option at the time when this VMOption was created.
/**
     * Returns the value of this VM option at the time when
     * this {@code VMOption} was created. The value could have been changed.
     *
     * @return the value of the VM option at the time when
     *         this {@code VMOption} 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.

Returns:where the value of this VM option came from.
/**
     * 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 
HotSpotDiagnosticMXBean.setVMOption method. 
Returns:true if this VM option is writeable; false otherwise.
/**
     * 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 {@code true} if this VM option is writeable; {@code false}
     * otherwise.
     */
    public boolean isWriteable() {
        return writeable;
    }

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

    
Returns a VMOption object represented by the given CompositeData. The given CompositeData must contain the following attributes: 


description



  Attribute Name
  Type






  name
  java.lang.String




  value
  java.lang.String




  origin
  java.lang.String




  writeable
  java.lang.Boolean








Params:
  • cd – CompositeData representing a VMOption
Throws:
Returns:a VMOption object represented by cd if cd is not null; null otherwise.
/**
     * Returns a {@code VMOption} object represented by the
     * given {@code CompositeData}. The given {@code CompositeData}
     * must contain the following attributes:
     *
     * <blockquote>
     * <table class="striped"><caption style="display:none">description</caption>
     * <thead>
     * <tr>
     *   <th scope="col" style="text-align:left">Attribute Name</th>
     *   <th scope="col" style="text-align:left">Type</th>
     * </tr>
     * </thead>
     * <tbody>
     * <tr>
     *   <th scope="row">name</th>
     *   <td>{@code java.lang.String}</td>
     * </tr>
     * <tr>
     *   <th scope="row">value</th>
     *   <td>{@code java.lang.String}</td>
     * </tr>
     * <tr>
     *   <th scope="row">origin</th>
     *   <td>{@code java.lang.String}</td>
     * </tr>
     * <tr>
     *   <th scope="row">writeable</th>
     *   <td>{@code java.lang.Boolean}</td>
     * </tr>
     * </tbody>
     * </table>
     * </blockquote>
     *
     * @param cd {@code CompositeData} representing a {@code VMOption}
     *
     * @throws IllegalArgumentException if {@code cd} does not
     *   represent a {@code VMOption} with the attributes described
     *   above.
     *
     * @return a {@code VMOption} object represented by {@code cd}
     *         if {@code cd} is not {@code null};
     *         {@code null} 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);
        }

    }
}