SymbolTable.java

package com.drawbridge.jsengine;

import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Set;

import com.drawbridge.jsengine.jsobjects.JSType;
import com.drawbridge.jsengine.jsobjects.JSUndefined;

public class SymbolTable
{
	private HashMap<String, SymbolTableEntry> mTable; 
	
	public SymbolTable(){
		mTable = new HashMap<String, SymbolTableEntry>();
	}
	
	public void add(String name, SymbolTableEntry entry) throws SymbolTableException{
		mTable.put(name, entry);
	}
	
	
	public void update(String name, JSType newValue) throws SymbolTableException{
		if(mTable.containsKey(name)){
			mTable.get(name).setVariable(newValue);
		}
		else{
			throw new SymbolTableException("Exception: " + name + "--No such symbol!");
		}
	}
	
	public SymbolTableEntry get(String name) throws SymbolTableException{
		if(mTable.containsKey(name)){
			return mTable.get(name);
		}
		else{
			throw new SymbolTableException("Exception: " + name + "--No such symbol!"); 
		}
	}
	
	public boolean contains(String name){
		if(mTable.containsKey(name))
			return true;
		else
			return false;
	}
	
	
	public void printSymbolTable(int increment){
		String incrementString = "";
		for(int i = 0; i < increment; i++)
			incrementString += " ";
		System.out.format(incrementString + "%10s\n", "Variables:");
		System.out.format(incrementString + "%20s%20s%20s\n", "Name:", "Object:", "value");
		
		Set<String> set = mTable.keySet();
		Iterator<String> it = set.iterator();
		while(it.hasNext()){
			String name = it.next().toString();
			SymbolTableEntry entry = mTable.get(name);
			JSType variable = entry.getVariable();
			if(variable == null) variable = new JSUndefined();
			System.out.format(incrementString + "%20s%20s%20s\n", name, variable.getClass().getSimpleName(), variable.toString());
		}
	}
	
	public LinkedList<JSType> getObjectOfType(JSType type){
		LinkedList<JSType> results = new LinkedList<JSType>();
		Set<String> set = mTable.keySet();
		Iterator<String> it = set.iterator();
		while(it.hasNext()){
			String name = it.next().toString();
			SymbolTableEntry entry = mTable.get(name);
			if(entry.getVariable().getClass().getName().equals(type.getClass().getName())){
				results.add((JSType) entry.getVariable());
			}
		}
		return results;
	}
	
	
	
	public class SymbolTableException extends Exception{
		private static final long	serialVersionUID	= -6787406324868368906L;
		public SymbolTableException() { super(); }
	    public SymbolTableException(String message) { super(message); }
		public SymbolTableException(String message, Throwable cause) { super(message, cause); }
		public SymbolTableException(Throwable cause) { super(cause); }
	}

}