SymbolTable.java

/**
 *  Copyright (C) 2010 dennis zhuang (killme2008@gmail.com)
 *
 *  This library 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 2.1 of the License, or
 *  (at your option) any later version.
 *
 *  This library 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 Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 **/
package com.googlecode.aviator.lexer;

import java.util.HashMap;
import java.util.Map;

import com.googlecode.aviator.lexer.token.Variable;


/**
 * Symbol table
 * 
 * @author dennis
 * 
 */
public class SymbolTable {

    private final Map<String, Variable> table = new HashMap<String, Variable>();


    public SymbolTable() {
        reserve("true", Variable.TRUE);
        reserve("false", Variable.FALSE);
        reserve("nil", Variable.NIL);
    }


    /**
     * Reserve variable
     * 
     * @param name
     * @param value
     */
    public void reserve(String name, Variable value) {
        table.put(name, value);
    }


    /**
     * Check variable has been reserved?
     * 
     * @param name
     * @return
     */
    public boolean contains(String name) {
        return table.containsKey(name);
    }


    /**
     * Get symbold table
     * 
     * @return
     */
    public Map<String, Variable> getTable() {
        return table;
    }


    /**
     * Get variable by name
     * 
     * @param name
     * @return
     */
    public Variable getVariable(String name) {
        return table.get(name);
    }
}