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/*
 * #%L
 * The AIBench Shell Plugin
 * %%
 * Copyright (C) 2006 - 2017 Daniel Glez-Peña and Florentino Fdez-Riverola
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 * 
 * This program 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 Lesser Public License for more details.
 * 
 * You should have received a copy of the GNU General Lesser Public
 * License along with this program.  If not, see
 * .
 * #L%
 */
package bsh;

public class Variable implements java.io.Serializable {
	private static final long serialVersionUID = 1L;

	static final int DECLARATION = 0, ASSIGNMENT = 1;

	/** A null type means an untyped variable */
	String name;

	Class type = null;

	String typeDescriptor;

	Object value;

	Modifiers modifiers;

	LHS lhs;

	Variable(String name, Class type, LHS lhs) {
		this.name = name;
		this.lhs = lhs;
		this.type = type;
	}

	Variable(String name, Object value, Modifiers modifiers) throws UtilEvalError {
		this(name, (Class) null/* type */, value, modifiers);
	}

	/**
	 * This constructor is used in class generation.
	 * 
	 * @param name the name of the variable.
	 * @param typeDescriptor the descriptor of the type of the variable.
	 * @param value the value of the variable. May be {@code null}.
	 * @param modifiers the modifiers of the variable.
	 * @throws UtilEvalError if an error occurs during evaluation.
	 */
	Variable(String name, String typeDescriptor, Object value, Modifiers modifiers) throws UtilEvalError {
		this(name, (Class) null/* type */, value, modifiers);
		this.typeDescriptor = typeDescriptor;
	}

	/**
	 * @param name the name of the variable.
	 * @param type the type of the variable.
	 * @param value the value of the variable. May be {@code null}.
	 * @param modifiers the modifiers of the variable.
	 * @throws UtilEvalError if an error occurs during evaluation.
	 */
	Variable(String name, Class type, Object value, Modifiers modifiers) throws UtilEvalError {
		this.name = name;
		this.type = type;
		this.modifiers = modifiers;
		setValue(value, DECLARATION);
	}

	/**
	 * Set the value of the typed variable.
	 * 
	 * @param value
	 *            should be an object or wrapped bsh Primitive type. if value is
	 *            null the appropriate default value will be set for the type:
	 *            e.g. false for boolean, zero for integer types.
	 * @param context
	 *            the value context
	 * @throws UtilEvalError
	 *             if an error occurs during evaluation.
	 */
	public void setValue(Object value, int context) throws UtilEvalError {

		// check this.value
		if (hasModifier("final") && this.value != null)
			throw new UtilEvalError("Final variable, can't re-assign.");

		if (value == null)
			value = Primitive.getDefaultValue(type);

		if (lhs != null) {
			lhs.assign(value, false/* strictjava */);
			return;
		}

		// TODO: should add isJavaCastable() test for strictJava
		// (as opposed to isJavaAssignable())
		if (type != null)
			value = Types.castObject(value, type, context == DECLARATION ? Types.CAST : Types.ASSIGNMENT);

		this.value = value;
	}

	/*
	 * Note: UtilEvalError here comes from lhs.getValue(). A Variable can
	 * represent an LHS for the case of an imported class or object field.
	 */
	Object getValue() throws UtilEvalError {
		if (lhs != null)
			return lhs.getValue();

		return value;
	}

	/**
	 * A type of {@code null} means loosely typed variable.
	 * 
	 * @return the variable type.
	 */
	public Class getType() {
		return type;
	}

	public String getTypeDescriptor() {
		return typeDescriptor;
	}

	public Modifiers getModifiers() {
		return modifiers;
	}

	public String getName() {
		return name;
	}

	public boolean hasModifier(String name) {
		return modifiers != null && modifiers.hasModifier(name);
	}

	public String toString() {
		return "Variable: " + super.toString() + " " + name + ", type:" + type + ", value:" + value + ", lhs = " + lhs;
	}
}