**** BEGIN LICENSE BLOCK *****
Version: EPL 2.0/GPL 2.0/LGPL 2.1
The contents of this file are subject to the Eclipse Public
License Version 2.0 (the "License"); you may not use this file
except in compliance with the License. You may obtain a copy of
the License at http://www.eclipse.org/legal/epl-v20.html
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) 2009-2011 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 *****
/**
 * **** BEGIN LICENSE BLOCK *****
 * Version: EPL 2.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Eclipse Public
 * License Version 2.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.eclipse.org/legal/epl-v20.html
 *
 * 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) 2009-2011 Yoko Harada <yokolet@gmail.com>
 *
 * 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 org.jruby.embed.internal.BiVariableMap;
import java.util.List;
import org.jruby.RubyObject;
import org.jruby.runtime.builtin.IRubyObject;
import org.jruby.runtime.builtin.InstanceVariables;

An implementation of BiVariable for a Ruby instance variable.
Author:
Yoko Harada /**
 * An implementation of BiVariable for a Ruby instance variable.
 *
 * @author Yoko Harada <yokolet@gmail.com>
 */
public class InstanceVariable extends AbstractVariable {

    private static final String VALID_NAME = "@([a-zA-Z]|_)([a-zA-Z]|_|\\d)*";

    
Returns an instance of this class. This factory method is used when an instance variable is put in BiVariableMap. 
Params:
runtime – Ruby runtime
name – a variable name
javaObject – Java object that should be assigned to.
Returns:
the instance of InstanceVariable/**
     * Returns an instance of this class. This factory method is used when an instance
     * variable is put in {@link BiVariableMap}.
     *
     * @param runtime Ruby runtime
     * @param name a variable name
     * @param javaObject Java object that should be assigned to.
     * @return the instance of InstanceVariable
     */
    public static BiVariable getInstance(RubyObject receiver, String name, Object... javaObject) {
        if (name.matches(VALID_NAME)) {
            return new InstanceVariable(receiver, name, javaObject);
        }
        return null;
    }

    private InstanceVariable(RubyObject receiver, String name, Object... javaObjects) {
        super(receiver, name, false);
        updateByJavaObject(receiver.getRuntime(), javaObjects);
    }

    
A constructor used when instance variables are retrieved from Ruby.
Params:
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 instance variable name
irubyObject – Ruby instance object/**
     * A constructor used when instance variables are retrieved from Ruby.
     *
     * @param receiver a receiver object that this variable/constant is originally in. When
     *        the variable/constant is originated from Ruby, receiver may not be null.
     * @param name the instance variable name
     * @param irubyObject Ruby instance object
     */
    public InstanceVariable(IRubyObject receiver, String name, IRubyObject irubyObject) {
        super(receiver, name, true, irubyObject);
    }

    InstanceVariable(RubyObject receiver, String name, IRubyObject irubyObject) {
        this((IRubyObject) receiver, name, irubyObject);
    }

    
Retrieves instance variables from Ruby after the evaluation.
Params:
runtime – Ruby runtime
receiver – receiver object returned when a script is evaluated.
vars – map to save retrieved instance variables./**
     * Retrieves instance variables from Ruby after the evaluation.
     *
     * @param runtime Ruby runtime
     * @param receiver receiver object returned when a script is evaluated.
     * @param vars map to save retrieved instance variables.
     */
    public static void retrieve(RubyObject receiver, BiVariableMap vars) {
        if (vars.isLazy()) return;
        updateInstanceVar(receiver, vars);
        updateInstanceVar(getTopSelf(receiver), vars);
    }

    static void updateInstanceVar(final RubyObject receiver, final BiVariableMap vars) {
        InstanceVariables ivars = receiver.getInstanceVariables();
        List<String> keys = ivars.getInstanceVariableNameList();
        for (String key : keys) {
            IRubyObject value = ivars.getInstanceVariable(key);
            BiVariable var = vars.getVariable(receiver, key);
            if (var != null) {
                var.setRubyObject(value);
            } else {
                var = new InstanceVariable(receiver, key, value);
                vars.update(key, var);
            }
        }
    }

    
Retrieves a instance variable by key from Ruby runtime after the evaluation.
This method is used when eager retrieval is off.
Params:
receiver – receiver object returned when a script is evaluated.
vars – map to save retrieved instance variables.
key – instace varible name/**
     * Retrieves a instance variable by key from Ruby runtime after the evaluation.
     * This method is used when eager retrieval is off.
     *
     * @param receiver receiver object returned when a script is evaluated.
     * @param vars map to save retrieved instance variables.
     * @param key instace varible name
     */
    public static void retrieveByKey(RubyObject receiver, BiVariableMap vars, String key) {
        InstanceVariables ivars = receiver.getInstanceVariables();

        // if the specified key doesn't exist, this method is called before the
        // evaluation. Don't update value in this case.
        if (!ivars.getInstanceVariableNameList().contains(key)) return;

        // the specified key is found, so let's update
        IRubyObject value = ivars.getInstanceVariable(key);
        BiVariable var = vars.getVariable(receiver, key);
        if (var != null) {
            var.setRubyObject(value);
        } else {
            var = new InstanceVariable(receiver, key, value);
            vars.update(key, var);
        }
    }


    
Returns enum type of this variable defined in BiVariable. 
Returns:
this enum type, BiVariable.Type.InstanceVariable./**
     * Returns enum type of this variable defined in {@link BiVariable}.
     *
     * @return this enum type, BiVariable.Type.InstanceVariable.
     */
    @Override
    public Type getType() {
        return Type.InstanceVariable;
    }

    
Returns true if the given name is a decent Ruby instance variable. Unless
returns false.
Params:
name – is a name to be checked.
Returns:
true if the given name is of a Ruby instance variable./**
     * Returns true if the given name is a decent Ruby instance variable. Unless
     * returns false.
     *
     * @param name is a name to be checked.
     * @return true if the given name is of a Ruby instance variable.
     */
    public static boolean isValidName(Object name) {
        return isValidName(VALID_NAME, name);
    }

    
Injects an instance variable value to a parsed Ruby script. This method is
invoked during EvalUnit#run() is executed.
Params:
runtime – is environment where a variable injection occurs
receiver – is the instance that will have variable injection./**
     * Injects an instance variable value to a parsed Ruby script. This method is
     * invoked during EvalUnit#run() is executed.
     *
     * @param runtime is environment where a variable injection occurs
     * @param receiver is the instance that will have variable injection.
     */
    @Override
    public void inject() {
        ((RubyObject) getReceiver()).setInstanceVariable(name.intern(), getRubyObject());
    }

    
Attempts to remove this variable from top self or receiver.
/**
     * Attempts to remove this variable from top self or receiver.
     *
     */
    @Override
    public void remove() {
        ((RubyObject) getReceiver()).removeInstanceVariable(name);
    }
}