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package com.sun.management.internal;

import java.util.*;
import com.sun.management.VMOption;
import com.sun.management.VMOption.Origin;
import java.security.AccessController;

Flag class is a helper class for constructing a VMOption. It has the static methods for getting the Flag objects, each corresponds to one VMOption.
/** * Flag class is a helper class for constructing a VMOption. * It has the static methods for getting the Flag objects, each * corresponds to one VMOption. * */
class Flag { private String name; private Object value; private Origin origin; private boolean writeable; private boolean external; Flag(String name, Object value, boolean writeable, boolean external, Origin origin) { this.name = name; this.value = value == null ? "" : value ; this.origin = origin; this.writeable = writeable; this.external = external; } Object getValue() { return value; } boolean isWriteable() { return writeable; } boolean isExternal() { return external; } VMOption getVMOption() { return new VMOption(name, value.toString(), writeable, origin); } static Flag getFlag(String name) { String[] names = new String[1]; names[0] = name; List<Flag> flags = getFlags(names, 1); if (flags.isEmpty()) { return null; } else { // flags should have only one element return flags.get(0); } } static List<Flag> getAllFlags() { int numFlags = getInternalFlagCount(); // Get all internal flags with names = null return getFlags(null, numFlags); } private static List<Flag> getFlags(String[] names, int numFlags) { Flag[] flags = new Flag[numFlags]; int count = getFlags(names, flags, numFlags); List<Flag> result = new ArrayList<>(); for (Flag f : flags) { if (f != null) { result.add(f); } } return result; } private static native String[] getAllFlagNames(); // getFlags sets each element in the given flags array // with a Flag object only if the name is valid and the // type is supported. The flags array may contain null elements. private static native int getFlags(String[] names, Flag[] flags, int count); private static native int getInternalFlagCount(); // These set* methods are synchronized on the class object // to avoid multiple threads updating the same flag at the same time. static synchronized native void setLongValue(String name, long value); static synchronized native void setDoubleValue(String name, double value); static synchronized native void setBooleanValue(String name, boolean value); static synchronized native void setStringValue(String name, String value); static { AccessController.doPrivileged( new java.security.PrivilegedAction<Void>() { public Void run() { System.loadLibrary("management"); return null; } }); initialize(); } private static native void initialize(); }