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**** BEGIN LICENSE BLOCK ***** Version: EPL 1.0/GPL 2.0/LGPL 2.1 The contents of this file are subject to the Eclipse Public License Version 1.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at Software distributed under the License is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the specific language governing rights and limitations under the License. Copyright (C) 2009-2012 Yoko Harada <> Alternatively, the contents of this file may be used under the terms of either of the GNU General Public License Version 2 or later (the "GPL"), or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), in which case the provisions of the GPL or the LGPL are applicable instead of those above. If you wish to allow use of your version of this file only under the terms of either the GPL or the LGPL, and not to allow others to use your version of this file under the terms of the EPL, indicate your decision by deleting the provisions above and replace them with the notice and other provisions required by the GPL or the LGPL. If you do not delete the provisions above, a recipient may use your version of this file under the terms of any one of the EPL, the GPL or the LGPL. **** END LICENSE BLOCK *****
 package org.jruby.embed.variable;
 import java.util.List;
 import java.util.Map;
An implementation of BiVariable for a Ruby constant.

Yoko Harada <>
 public class Constant extends AbstractVariable {
     private static String pattern = "[A-Z]([a-zA-Z]|_)([a-zA-Z]|_|\\d)*";
     private boolean initialized = false;

Returns an instance of this class. This factory method is used when a constant is put in org.jruby.embed.internal.BiVariableMap.

name a variable name
javaObject Java object that should be assigned to.
the instance of Constant
     public static BiVariable getInstance(RubyObject receiverString nameObject... javaObject) {
         if (name.matches()) {
             return new Constant(receivernamejavaObject);
         return null;
     private Constant(RubyObject receiverString nameObject... javaObjects) {
         updateByJavaObject(receiver.getRuntime(), javaObjects);

A constructor used when constants are retrieved from Ruby.

receiver a receiver object that this variable/constant is originally in. When the variable/constant is originated from Ruby, receiver may not be null.
name the constant name
irubyObject Ruby constant object
     Constant(IRubyObject receiverString nameIRubyObject irubyObject) {
     void markInitialized() {
         this. = true;

Retrieves constants from Ruby after the evaluation or method invocation.

runtime Ruby runtime
receiver receiver object returned when a script is evaluated.
vars map to save retrieved constants.
     public static void retrieve(RubyObject receiverBiVariableMap vars) {
         if (vars.isLazy()) return;
         // user defined constants of top level go to a super class
         // Constants might have the same names but different receivers.
        RubyObject topSelf = (RubyObject)receiver.getRuntime().getTopSelf();
    private static void updateARGV(IRubyObject receiver, BiVariableMap vars) {
        String name = "ARGV".intern();
        IRubyObject argv = receiver.getRuntime().getTopSelf().getMetaClass().fastGetConstant(name);
        if (argv == null || (argv instanceof RubyNil)) return;
        BiVariable var;  // This var is for ARGV.
        // ARGV constant should be only one
        if (vars.containsKey((Object)name)) {
            var = vars.getVariable((RubyObject)receiver.getRuntime().getTopSelf(), name);
        } else {
            var = new Constant(receiver.getRuntime().getTopSelf(), name, argv);
            ((Constant) var).markInitialized();
            vars.update(name, var);
    private static void updateConstantsOfSuperClass(RubyObject receiverBiVariableMap vars) {
        // Super class has many many constants, so this method updates only
        // constans in BiVariableMap.
        Map<StringRubyModule.ConstantEntrymap =
        List<BiVariablevariables = vars.getVariables();
            // Need to check that this constant has been stored in BiVariableMap.
        for (BiVariable variable : variables) {
            if (variable.getType() == .) {
                if (map.containsKey(variable.getName())) {
                    IRubyObject value = map.get(variable.getName()).;
    private static void updateConstants(RubyObject receiverBiVariableMap vars) {
        Collection<Stringnames = receiver.getMetaClass().getConstantNames();
        for (String name : names) {
            IRubyObject value = receiver.getMetaClass().getConstant(name);
            BiVariable var = null;
            List<StringsavedNames = vars.getNames();
            // Need to check that this constant has been stored in BiVariableMap.
            for (int i=0; i<savedNames.size(); i++) {
                if (name.equals(savedNames.get(i))) {
                    var = (BiVariablevars.getVariables().get(i);
                    if (receiver == var.getReceiver()) {
                    } else {
                        var = null;
            if (var == null) {
                var = new Constant(receivernamevalue);

Retrieves a constant by key from Ruby runtime after the evaluation. This method is used when eager retrieval is off.

receiver receiver object returned when a script is evaluated.
vars map to save retrieved instance variables.
key instace varible name
    public static void retrieveByKey(RubyObject receiverBiVariableMap varsString key) {
        // if the specified key doesn't exist, this method is called before the
        // evaluation. Don't update value in this case.
        IRubyObject value = null;
        if (receiver.getMetaClass().getConstantNames().contains(key)) {
            value = receiver.getMetaClass().getConstant(key);
        } else if (receiver.getRuntime().getTopSelf().getMetaClass().getConstantNames().contains(key)) {
            value = receiver.getRuntime().getTopSelf().getMetaClass().getConstant(key);
        } else if (receiver.getRuntime().getTopSelf().getMetaClass().getSuperClass().getConstantNames().contains(key)) {
            value = receiver.getRuntime().getTopSelf().getMetaClass().getSuperClass().getConstant(key);
        if (value == nullreturn;
        // the specified key is found, so let's update
        BiVariable var = vars.getVariable(receiverkey);
        if (var != null) {
        } else {
            var = new Constant(receiverkeyvalue);

Returns enum type of this variable defined in BiVariable.

this enum type, BiVariable.Type.Constant.
    public Type getType() {
        return .;

Returns true if the given name is a decent Ruby constant. Unless returns false.

name is a name to be checked.
true if the given name is of a Ruby constant.
    public static boolean isValidName(Object name) {
        return isValidName(name);

Injects a constant value to a parsed Ruby script. This method is invoked during EvalUnit#run() is executed.
    public void inject() {
        if ( == .getRuntime().getTopSelf()) {
            RubyModule rubyModule = getRubyClass(.getRuntime());
            if (rubyModule == nullrubyModule = .getRuntime().getCurrentContext().getRubyClass();
            if (rubyModule == nullreturn;
        } else {
         = true;

Attempts to remove this constant from top self or receiver.
    public void remove() {
        IRubyObject rubyName = JavaUtil.convertJavaToRuby(.getRuntime(), );
        if (.getMetaClass().getConstantNames().contains()) {
            .getMetaClass().remove_const(.getRuntime().getCurrentContext(), rubyName);
        } else if (.getRuntime().getTopSelf().getMetaClass().getConstantNames().contains()) {
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